Quantitative Analysis of CXCL4 and TLR8 signaling crosstalk in human primary monocytes by RNA-Seq
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ABSTRACT: To gain a comprehensive understanding of gene regulation in CXCL4 and TLR8 signaling crosstalk, we treated primary human blood monocytes with CXCL4 and TLR8 ssRNA ligand ORN8L for 6 h and performed transcriptomic analysis via RNA-seq. We observed that CXCL4 interacted with TLR8 ssRNA ligand and triggered inflammatory cytokine storm including IL6, IL12p40, TNF and IFNβ, and pro-fibrotic gene expression and activated NLRP3 inflammasome leading to interleukin-1β (IL-1β) secretion and pyroptosis in human blood monocytes.
Project description:To gain a comprehensive understanding of gene regulation in CXCL4 and TLR8 signaling crosstalk, we treated primary human blood monocytes with CXCL4 and TLR8 ssRNA ligand ORN8L for 6 h and performed transcriptomic analysis via RNA-seq. We observed that CXCL4 interacted with TLR8 ssRNA ligand and triggered inflammatory cytokine storm including IL6, IL12p40, TNF and IFNβ, and pro-fibrotic gene expression and activated NLRP3 inflammasome leading to interleukin-1β (IL-1β) secretion and pyroptosis in human blood monocytes.
Project description:To investigate the function of RIPK3 in regulation of IFN response and inflammatory response in human monocytes stimulated with CXCL4 and TLR8, We blocks (CXCL4 + TLR8)-induced pyroptosis and RIPK3 activation using necrosulfonamide (NSA, 5 µM) and GSK'872 (10 µM) and measure gene expression genome-wide with RNA-seq.
Project description:Mechanistic studies have revealed that TLR8 senses single-stranded RNA (ssRNA) fragments, processed via synergistic cleavage by ribonucleases (RNase) T2 and RNase A family members. Processing by these RNases releases uridines and purine-terminated residues resulting in TLR8 activation. Monocytes show high expression of RNase 6, yet this RNase has not been analyzed for its physiological contribution to recognition of bacterial RNA by TLR8. Herein, we characterized molecular RNase 6 cleavage mechanisms. BLaER1 RNASE6-/- cells showed a dampened TLR8-dependent response upon stimulation with isolated bacterial RNA (bRNA) but also upon infection with live whole bacteria. Pretreatment of bacterial RNA with recombinant RNase 6 generated fragments that induced stimulation in RNASE6 knockout cells. 2’O-RNA methyl modification, when introduced at the first uridine in the UA dinucleotide, impaired upstream processing by RNase 6 and dampened TLR8 stimulation. In summary, this data shows that RNase 6 plays a critical role in the processing of bacterial RNA by generating uridine-terminated breakdown products that ultimately activate TLR8.
Project description:Human blood monocytes were differentiated over six days with either 100 ng/ml M-CSF or 1 umol/l CXCL4 In atherosclerotic arteries, blood monocytes differentiate to macrophages in the presence of growth factors like macrophage colony-stimulation factor (MCSF) and chemokines like platelet factor 4 (CXCL4). To compare the gene expression signature of CXCL4-induced macrophages with MCSF-induced macrophages or macrophages polarized with IFN-γ/LPS (M1) or IL-4 (M2), we cultured primary human peripheral blood monocytes for six days. mRNA expression was measured by Affymetrix gene chips and differences were analyzed by Local Pooled Error test, Profile of Complex Functionality and Gene Set Enrichment Analysis. 375 genes were differentially expressed between MCSF- and CXCL4-induced macrophages, 206 of them overexpressed in CXCL4 macrophages coding for genes implicated in the inflammatory/immune response, antigen processing/presentation, and lipid metabolism. CXCL4-induced macrophages overexpressed some M1 and M2 genes and the corresponding cytokines at the protein level, however, their transcriptome clustered with neither M1 nor M2 transcriptomes. They almost completely lost the ability to phagocytose zymosan beads. Genes linked to atherosclerosis were not consistently up- or downregulated. Scavenger receptors showed lower and cholesterol efflux transporters higher expression in CXCL4- than MCSF-induced macrophages, resulting in lower LDL content. We conclude that CXCL4 induces a unique macrophage transcriptome distinct from known macrophage types, defining a new macrophage differentiation that we propose to call M4. two MCSF samples and two CXCL4 samples
Project description:Goal was to detect differences in response to TLR7 versus TLR8 agonists in human monocytes from healthy donors 3 deidentified donors from the Red Cross, monocytes from each donor incubated overnight with either vehicle, TLR7 agonist or TLR8 agonist
Project description:Human blood monocytes were differentiated over six days with either 100 ng/ml M-CSF or 1 umol/l CXCL4 In atherosclerotic arteries, blood monocytes differentiate to macrophages in the presence of growth factors like macrophage colony-stimulation factor (MCSF) and chemokines like platelet factor 4 (CXCL4). To compare the gene expression signature of CXCL4-induced macrophages with MCSF-induced macrophages or macrophages polarized with IFN-γ/LPS (M1) or IL-4 (M2), we cultured primary human peripheral blood monocytes for six days. mRNA expression was measured by Affymetrix gene chips and differences were analyzed by Local Pooled Error test, Profile of Complex Functionality and Gene Set Enrichment Analysis. 375 genes were differentially expressed between MCSF- and CXCL4-induced macrophages, 206 of them overexpressed in CXCL4 macrophages coding for genes implicated in the inflammatory/immune response, antigen processing/presentation, and lipid metabolism. CXCL4-induced macrophages overexpressed some M1 and M2 genes and the corresponding cytokines at the protein level, however, their transcriptome clustered with neither M1 nor M2 transcriptomes. They almost completely lost the ability to phagocytose zymosan beads. Genes linked to atherosclerosis were not consistently up- or downregulated. Scavenger receptors showed lower and cholesterol efflux transporters higher expression in CXCL4- than MCSF-induced macrophages, resulting in lower LDL content. We conclude that CXCL4 induces a unique macrophage transcriptome distinct from known macrophage types, defining a new macrophage differentiation that we propose to call M4.