scholarly journals Trem2promotes anti-inflammatory responses in microglia and is suppressed under pro-inflammatory conditions

2018 ◽  
Author(s):  
Wenfei Liu ◽  
Orjona Taso ◽  
Rui Wang ◽  
Sevinc Bayram ◽  
Pablo Garcia-Reitboeck ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Inflammatory Responses ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Similar Expression Profile ◽  
Inflammatory Conditions ◽  
Phenotype Comparison ◽  
Inflammatory Phenotype ◽  
Similar Phenotype ◽  
Anti Inflammatory

AbstractGenome-wide association studies have reported that, amongst other microglial genes, variants inTREM2can profoundly increase the incidence of developing Alzheimer’s disease (AD). We have investigated the role of TREM2 in primary microglial cultures from wild type mice by using siRNA to decreaseTrem2expression, and in parallel from knock-in mice heterozygous or homozygous for theTrem2R47H AD risk variant. The prevailing phenotype ofTrem2R47H knock-in mice was decreased expression levels ofTrem2in microglia, which resulted in decreased density of microglia in the hippocampus. Overall, primary microglia with reducedTrem2expression, either by siRNA or from the R47H knock-in mice, displayed a similar phenotype. Comparison of the effects of decreasedTrem2expression under conditions of LPS pro-inflammatory or IL-4 anti-inflammatory stimulation revealed the importance ofTrem2in driving a number of the genes up-regulated in the anti-inflammatory phenotype. RNA-seq analysis showed that IL-4 induced the expression of a programme of genes includingArg1andAp1b1in microglia, which showed an attenuated response to IL-4 whenTrem2expression was decreased. Genes showing a similar expression profile toArg1were enriched for STAT6 transcription factor recognition elements in their promoter, andTrem2knockdown decreased levels of the transcription factor STAT6. LPS-induced pro-inflammatory stimulation suppressedTrem2expression, thus preventing TREM2’s anti-inflammatory drive. Given that anti-inflammatory signaling is associated with tissue repair, understanding the signaling mechanisms downstream ofTrem2in coordinating the pro- and anti-inflammatory balance of microglia, particularly mediating effects of the IL-4-regulated anti-inflammatory pathway, has important implications for fighting neurodegenerative disease.Graphical abstract

scholarly journals Trem2 promotes anti-inflammatory responses in microglia and is suppressed under pro-inflammatory conditions

2020 ◽  
Vol 29 (19) ◽  
pp. 3224-3248
Author(s):  
Wenfei Liu ◽  
Orjona Taso ◽  
Rui Wang ◽  
Sevinc Bayram ◽  
Andrew C Graham ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Similar Expression Profile ◽  
Inflammatory Conditions ◽  
Genome Wide ◽  
Phenotype Comparison ◽  
Inflammatory Phenotype ◽  
Similar Phenotype ◽  
Anti Inflammatory

Abstract Genome-wide association studies have reported that, amongst other microglial genes, variants in TREM2 can profoundly increase the incidence of developing Alzheimer’s disease (AD). We have investigated the role of TREM2 in primary microglial cultures from wild type mice by using siRNA to decrease Trem2 expression, and in parallel from knock-in mice heterozygous or homozygous for the Trem2 R47H AD risk variant. The prevailing phenotype of Trem2 R47H knock-in mice was decreased expression levels of Trem2 in microglia, which resulted in decreased density of microglia in the hippocampus. Overall, primary microglia with reduced Trem2 expression, either by siRNA or from the R47H knock-in mice, displayed a similar phenotype. Comparison of the effects of decreased Trem2 expression under conditions of lipopolysaccharide (LPS) pro-inflammatory or IL-4 anti-inflammatory stimulation revealed the importance of Trem2 in driving a number of the genes up-regulated in the anti-inflammatory phenotype. RNA-seq analysis showed that IL-4 induced the expression of a program of genes including Arg1 and Ap1b1 in microglia, which showed an attenuated response to IL-4 when Trem2 expression was decreased. Genes showing a similar expression profile to Arg1 were enriched for STAT6 transcription factor recognition elements in their promoter, and Trem2 knockdown decreased levels of STAT6. LPS-induced pro-inflammatory stimulation suppressed Trem2 expression, thus preventing TREM2’s anti-inflammatory drive. Given that anti-inflammatory signaling is associated with tissue repair, understanding the signaling mechanisms downstream of Trem2 in coordinating the pro- and anti-inflammatory balance of microglia, particularly mediating effects of the IL-4-regulated anti-inflammatory pathway, has important implications for fighting neurodegenerative disease.

scholarly journals The Transcription Factor MAFF Regulates an Atherosclerosis Relevant Network Connecting Inflammation and Cholesterol Metabolism

Circulation ◽  
2021 ◽  
Author(s):  
Moritz von Scheidt ◽  
Yuqi Zhao ◽  
Thomas Q. de Aguiar Vallim ◽  
Nam Che ◽  
Michael Wierer ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Molecular Mechanisms ◽  
Prediction Models ◽  
Cholesterol Metabolism ◽  
Association Studies ◽  
Experimental Studies ◽  
Genome Wide Association Studies ◽  
Inflammatory Conditions

Background: Coronary artery disease (CAD) is a multifactorial condition with both genetic and exogenous causes. The contribution of tissue specific functional networks to the development of atherosclerosis remains largely unclear. The aim of this study was to identify and characterise central regulators and networks leading to atherosclerosis. Methods: Based on several hundred genes known to affect atherosclerosis risk in mouse (as demonstrated in knock-out models) and human (as shown by genome-wide association studies (GWAS)) liver gene regulatory networks were modeled. The hierarchical order and regulatory directions of genes within the network were based on Bayesian prediction models as well as experimental studies including chromatin immunoprecipitation DNA-Sequencing (ChIP-Seq), ChIP mass spectrometry (ChIP-MS), overexpression, siRNA knockdown in mouse and human liver cells, and knockout mouse experiments. Bioinformatics and correlation analyses were used to clarify associations between central genes and CAD phenotypes in both human and mouse. Results: The transcription factor MAFF interacted as a key driver of a liver network with three human genes at CAD GWAS loci and eleven atherosclerotic murine genes. Most importantly, expression levels of the low-density lipoprotein receptor ( LDLR ) gene correlated with MAFF in 600 CAD patients undergoing bypass surgery (STARNET) and a hybrid mouse diversity panel involving 105 different inbred mouse strains. Molecular mechanisms of MAFF were tested under non-inflammatory conditions showing a positive correlation between MAFF and LDLR in vitro and in vivo . Interestingly, after LPS stimulation (inflammatory conditions) an inverse correlation between MAFF and LDLR in vitro and in vivo was observed. ChIP-MS revealed that the human CAD GWAS candidate BACH1 assists MAFF in the presence of LPS stimulation with respective heterodimers binding at the MAF recognition element (MARE) of the LDLR promoter to transcriptionally downregulate LDLR expression. Conclusions: The transcription factor MAFF was identified as a novel central regulator of an atherosclerosis/CAD relevant liver network. MAFF triggered context specific expression of LDLR and other genes known to affect CAD risk. Our results suggest that MAFF is a missing link between inflammation, lipid and lipoprotein metabolism and a possible treatment target.

Abstract 351: Mechano-sensitive Ppap2b Regulates Endothelial Responses to Athero-relevant Hemodynamic Forces

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Congqing Wu ◽  
Cheng-Hsiang Kuo ◽  
Chan Woo Kim ◽  
Ru-Ting Huang ◽  
Anna Birukova ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Lysophosphatidic Acid ◽  
Association Studies ◽  
Integral Membrane Protein ◽  
Genome Wide Association Studies ◽  
Cell Alignment ◽  
Disturbed Flow ◽  
Inflammatory Phenotype ◽  
Anti Inflammatory

Rationale: PhosPhatidic-Acid-Phosphatase-type-2B (PPAP2B), an integral membrane protein that inactivates lysophosphatidic acid, was implicated in coronary artery disease (CAD) by genome-wide association studies (GWAS). However, it is unclear whether GWAS-identified CAD genes including PPAP2B participate in mechanotransduction mechanisms by which vascular endothelia respond to local athero-relevant blood flows that contribute to the regional nature of atherosclerosis. Approach and Results: Reduced endothelial PPAP2B was detected in vivo in swine aortic arch exposed to chronic disturbed flow and in mouse carotid artery subjected to surgically-induced acute disturbed flow. In culture, elevated PPAP2B was measured in human aortic endothelial cells (HAEC) under athero-protective flow mimicking hemodynamics of human distal carotid artery when compared with athero-susceptible waveform representing flow in carotid sinus. Disturbed flow-induced miR-92a was identified as a direct posttranscriptional inhibitor of mechano-sensitive PPAP2B. PPAP2B suppression abrogated athero-protection of unidirectional flow, shown by elevation of inflammatory genes. Inhibition of lysophosphatidic acid receptor 1 restored the flow-dependent, anti-inflammatory phenotype in PPAP2B-deficient cells. Moreover, PPAP2B inhibition resulted in myosin-light-chain phosphorylation and intercellular gaps, which were abolished by inhibition of lysophosphatidic acid receptors 1 and 2. Expression-quantitative-trait-locus-mapping demonstrated PPAP2B CAD risk allele is not linked to PPAP2B expression in various human tissues but significantly associated with reduced PPAP2B in HAEC. Conclusions: Athero-relevant flows dynamically modulate endothelial PPAP2B expression through miR-92a regulation. Mechano-sensitive PPAP2B plays an indispensable role in mediating cell alignment, promoting anti-inflammatory phenotype and maintaining vascular integrity of endothelial monolayer under athero-protective flow.

scholarly journals Anti-Inflammatory and Immunomodulatory Effects of the Grifola frondosa Natural Compound o-Orsellinaldehyde on LPS-Challenged Murine Primary Glial Cells. Roles of NF-κβ and MAPK

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 806
Author(s):  
Sarah Tomas-Hernandez ◽  
Jordi Blanco ◽  
Santiago Garcia-Vallvé ◽  
Gerard Pujadas ◽  
María José Ojeda-Montes ◽  
...  
Keyword(s):  
Natural Compound ◽  
Underlying Disease ◽  
Grifola Frondosa ◽  
Beneficial Effects ◽  
Inflammatory Conditions ◽  
Inflammatory Mechanism ◽  
Inflammatory Phenotype ◽  
Mice Brain ◽  
Anti Inflammatory

In response to foreign or endogenous stimuli, both microglia and astrocytes adopt an activated phenotype that promotes the release of pro-inflammatory mediators. This inflammatory mechanism, known as neuroinflammation, is essential in the defense against foreign invasion and in normal tissue repair; nevertheless, when constantly activated, this process can become detrimental through the release of neurotoxic factors that amplify underlying disease. In consequence, this study presents the anti-inflammatory and immunomodulatory properties of o-orsellinaldehyde, a natural compound found by an in silico approach in the Grifola frondosa mushroom, in astrocytes and microglia cells. For this purpose, primary microglia and astrocytes were isolated from mice brain and cultured in vitro. Subsequently, cells were exposed to LPS in the absence or presence of increasing concentrations of this natural compound. Specifically, the results shown that o-orsellinaldehyde strongly inhibits the LPS-induced inflammatory response in astrocytes and microglia by decreasing nitrite formation and downregulating iNOS and HO-1 expression. Furthermore, in microglia cells o-orsellinaldehyde inhibits NF-κB activation; and potently counteracts LPS-mediated p38 kinase and JNK phosphorylation (MAPK). In this regard, o-orsellinaldehyde treatment also induces a significant cell immunomodulation by repolarizing microglia toward the M2 anti-inflammatory phenotype. Altogether, these results could partially explain the reported beneficial effects of G. frondosa extracts on inflammatory conditions.

scholarly journals Selected Uterine Immune Events Associated With the Establishment of Pregnancy in the Dog

2021 ◽  
Vol 7 ◽  
Author(s):  
Miguel Tavares Pereira ◽  
Renata Nowaczyk ◽  
Rita Payan-Carreira ◽  
Sonia Miranda ◽  
Selim Aslan ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Trophoblast Invasion ◽  
Tnf Receptors ◽  
Related Factors ◽  
Inflammatory Conditions ◽  
Inflammatory Signals ◽  
Anti Inflammatory ◽  
Uterine Glands ◽  
Post Implantation ◽  
Implantation Period

In the dog, implantation takes place at approximately 17 days of embryonal life and, while exposed to relatively high circulating progesterone concentrations, embryos presence is required for the formation of decidua. Furthermore, a balance between pro- and anti-inflammatory responses in conceptus-maternal communication is crucial for the onset of pregnancy. Strikingly, the understanding of such immune mechanisms in canine reproduction is still elusive. Here, canine uterine samples from pre-implantation (day 10–12, E+) and corresponding non-pregnant controls (E–), implantation (day 17, Imp) and post-implantation (day 18–25, Post-Imp) stages of pregnancy were used to investigate the expression and localization of several immune-related factors. The most important findings indicate increased availability of CD4, MHCII, NCR1, IDO1, AIF1, CD25, CCR7, and IL6 in response to embryo presence (E+), while FoxP3 and CCL3 were more abundant in E– samples. Implantation was characterized by upregulated levels of FoxP3, IL12a, ENG, and CDH1, whereas CD4, CCR7, IL8, and -10 were less represented. Following implantation, decreased transcript levels of TNFR1, MHCII, NCR1, TLR4, CD206, FoxP3, and IL12a were observed concomitantly with the highest expression of IL6 and IL1β. MHCII, CD86, CD206, CD163, TNFα, IDO1, and AIF1 were immunolocalized in macrophages, CD4 and Nkp46 in lymphocytes, and some signals of IDO1, AIF1, and TNF-receptors could also be identified in endothelial cells and/or uterine glands. Cumulatively, new insights regarding uterine immunity in the peri-implantation period are provided, with apparent moderated pro-inflammatory signals prevailing during pre-implantation, while implantation and early trophoblast invasion appear to be associated with immunomodulatory and rather anti-inflammatory conditions.

scholarly journals The CXCR6/CXCL16 axis links inflamm-aging to disease severity in COVID-19 patients

2021 ◽  
Author(s):  
Daniel J. Payne ◽  
Surita Dalal ◽  
Richard Leach ◽  
Richard Parker ◽  
Stephen Griffin ◽  
...  
Keyword(s):  
T Cells ◽  
Inflammatory Responses ◽  
Association Studies ◽  
Significant Risk ◽  
Genome Wide Association Studies ◽  
Genome Wide ◽  
Inflammatory State ◽  
Negative Controls ◽  
Severe Lung Disease

AbstractAdvancing age and chronic health conditions, significant risk factors for severe COVID-19, are associated with a pro-inflammatory state, termed inflamm-aging. CXCR6+ T cells are known to traffic to the lung and have been reported to increase with age. The ligand of CXCR6, CXCL16, is constitutively expressed in the lung and upregulated during inflammatory responses and the CXCR6/CXCL16 axis is associated with severe lung disease and pneumonia. Genome-wide association studies have also recently identified 3p21.31, encompassing the CXCR6 gene, as a susceptibility locus for severe COVID-19. We assessed numbers T cells expressing the chemokine receptor CXCR6 and plasma levels of CXCL16, in control and COVID-19 patients. Results demonstrated that circulating CD8+CXCR6+ T cells were significantly elevated with advancing age, yet virtually absent in patients with severe COVID-19. Peripheral levels of CXCL16 were significantly upregulated in severe COVID-19 patients compared to either mild COVID-19 patients or SARS-CoV-2 negative controls. This study supports a significant role of the CXCR6/CXCL16 axis in the immunopathogenesis of severe COVID-19.

scholarly journals Hybrid allele-specific ChIP-Seq analysis links variation in transcription factor binding to traits in maize

2021 ◽  
Author(s):  
Thomas Hartwig ◽  
Michael Banf ◽  
Gisele Prietsch ◽  
Julia Engelhorn ◽  
Jinliang Yang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Target Genes ◽  
Phenotypic Diversity ◽  
Association Studies ◽  
Chromatin Accessibility ◽  
Genome Wide Association Studies ◽  
Functional Variants ◽  
Genome Wide ◽  
Allele Specific ◽  
Hybrid Allele

Abstract Variation in transcriptional regulation is a major cause of phenotypic diversity. Genome-wide association studies (GWAS) have shown that most functional variants reside in non-coding regions, where they potentially affect transcription factor (TF) binding and chromatin accessibility to alter gene expression. Pinpointing such regulatory variations, however, remains challenging. Here, we developed a hybrid allele-specific chromatin binding sequencing (HASCh-seq) approach and identified variations in target binding of the brassinosteroid (BR) responsive transcription factor ZmBZR1 in maize. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) in B73xMo17 F1s identified thousands of target genes of ZmBZR1. Allele-specific ZmBZR1 binding (ASB) was observed for about 14.3% of target genes. It correlated with over 550 loci containing sequence variation in BZR1-binding motifs and over 340 loci with haplotype-specific DNA methylation, linking genetic and epigenetic variations to ZmBZR1 occupancy. Comparison with GWAS data linked hundreds of ASB loci to important yield, growth, and disease-related traits. Our study provides a robust method for analyzing genome-wide variations of transcription factor occupancy and identified genetic and epigenetic variations of the BR response transcription network in maize.

scholarly journals Predicting the effects of SNPs on transcription factor binding affinity

2019 ◽  
Author(s):  
Sierra S Nishizaki ◽  
Natalie Ng ◽  
Shengcheng Dong ◽  
Robert S Porter ◽  
Cody Morterud ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Binding Affinity ◽  
Association Studies ◽  
Transcription Factor Binding ◽  
Supplementary Information ◽  
Genome Wide Association Studies ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Factor Binding ◽  
Genome Wide

Abstract Motivation Genome-wide association studies have revealed that 88% of disease-associated single-nucleotide polymorphisms (SNPs) reside in noncoding regions. However, noncoding SNPs remain understudied, partly because they are challenging to prioritize for experimental validation. To address this deficiency, we developed the SNP effect matrix pipeline (SEMpl). Results SEMpl estimates transcription factor-binding affinity by observing differences in chromatin immunoprecipitation followed by deep sequencing signal intensity for SNPs within functional transcription factor-binding sites (TFBSs) genome-wide. By cataloging the effects of every possible mutation within the TFBS motif, SEMpl can predict the consequences of SNPs to transcription factor binding. This knowledge can be used to identify potential disease-causing regulatory loci. Availability and implementation SEMpl is available from https://github.com/Boyle-Lab/SEM_CPP. Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals The pancreatic islet β-cell-enriched transcription factor Pdx-1 regulates Slc30a8 gene transcription through an intronic enhancer

2010 ◽  
Vol 433 (1) ◽  
pp. 95-105 ◽  
Author(s):  
Lynley D. Pound ◽  
Yan Hang ◽  
Suparna A. Sarkar ◽  
Yingda Wang ◽  
Laurel A. Milam ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Pancreatic Islet ◽  
Fusion Gene ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Β Cells ◽  
Β Cell ◽  
Specific Expression

The SLC30A8 gene encodes the zinc transporter ZnT-8, which provides zinc for insulin-hexamer formation. Genome-wide association studies have shown that a polymorphic variant in SLC30A8 is associated with altered susceptibility to Type 2 diabetes and we recently reported that glucose-stimulated insulin secretion is decreased in islets isolated from Slc30a8-knockout mice. The present study examines the molecular basis for the islet-specific expression of Slc30a8. VISTA analyses identified two conserved regions in Slc30a8 introns 2 and 3, designated enhancers A and B respectively. Transfection experiments demonstrated that enhancer B confers elevated fusion gene expression in both βTC-3 cells and αTC-6 cells. In contrast, enhancer A confers elevated fusion gene expression selectively in βTC-3 and not αTC-6 cells. These data suggest that enhancer A is an islet β-cell-specific enhancer and that the mechanisms controlling Slc30a8 expression in α- and β-cells are overlapping, but distinct. Gel retardation and ChIP (chromatin immunoprecipitation) assays revealed that the islet-enriched transcription factor Pdx-1 binds enhancer A in vitro and in situ respectively. Mutation of two Pdx-1-binding sites in enhancer A markedly reduces fusion gene expression suggesting that this factor contributes to Slc30a8 expression in β-cells, a conclusion consistent with developmental studies showing that restriction of Pdx-1 to pancreatic islet β-cells correlates with the induction of Slc30a8 gene expression and ZnT-8 protein expression in vivo.

scholarly journals Epigenetic Modifications and Therapy in Uveitis

2021 ◽  
Vol 9 ◽  
Author(s):  
Yanli Zou ◽  
Jing Jing Li ◽  
Wei Xue ◽  
Xiangbin Kong ◽  
Hucheng Duan ◽  
...  
Keyword(s):  
Immune Responses ◽  
Association Studies ◽  
Intraocular Inflammation ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Epigenetic Mechanisms ◽  
Inflammatory Conditions ◽  
Genome Wide ◽  
Different Types ◽  
Vkh Disease

Uveitis is a sight-threatening intraocular inflammation, and the exact pathogenesis of uveitis is not yet clear. Recent studies, including multiple genome-wide association studies (GWASs), have identified genetic variations associated with the onset and progression of different types of uveitis, such as Vogt–Koyanagi–Harada (VKH) disease and Behcet’s disease (BD). However, epigenetic regulation has been shown to play key roles in the immunoregulation of uveitis, and epigenetic therapies are promising treatments for intraocular inflammation. In this review, we summarize recent advances in identifying epigenetic programs that cooperate with the physiology of intraocular immune responses and the pathology of intraocular inflammation. These attempts to understand the epigenetic mechanisms of uveitis may provide hope for the future development of epigenetic therapies for these devastating intraocular inflammatory conditions.

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