Project description:The transcription factors that regulate gene expression in stimulated neutrophils are poorly characterized. Herein, we found that the genomic distribution of the myeloid lineage determining transcription factors PU.1 and C/EBPβ, as well as that of the histone modification H3K27Ac, which marks active chromatin, significantly change in human neutrophils treated with R848, a ligand of TLR8.
Project description:The transcription factors that regulate gene expression in stimulated neutrophils are poorly characterized. Herein, we found that the genomic distribution of the myeloid lineage determining transcription factors PU.1 and C/EBPβ, as well as that of the histone modification H3K27Ac, which marks active chromatin, significantly change in human neutrophils treated with R848, a ligand of TLR8.
Project description:The transcription factors that regulate gene expression in stimulated neutrophils are poorly characterized. Herein, we found that the genomic distribution of the myeloid lineage determining transcription factors PU.1 and C/EBPβ, as well as that of the histone modification H3K27Ac, which marks active chromatin, significantly change in human neutrophils treated with R848, a ligand of TLR8.
Project description:COVID-19 disease is characterized by a dysregulation of the innate arm of the immune system. However, the mechanisms whereby innate immune cells, including neutrophils, become activated in patients are not completely understood. Recently, we showed that a GU-rich RNA sequence from SARS-CoV-2 genome (i.e., SCV2-RNA2) activates dendritic cells. To clarify whether human neutrophils may also represent targets of SCV2-RNA2, neutrophils were treated with either SCV2-RNA2 or, as control, R848 (a TLR7/8 ligand), and then analysed for several functional assays and also subjected to RNA-seq experiments. Results highlight a remarkable response of neutrophils to SCV2-RNA2 in terms of TNFa, IL1ra, CXCL8 production, apoptosis delay, modulation of CD11b and CD62L expression and release of neutrophil extracellular traps. By RNA-seq experiments, we observed that SCV2-RNA2 promotes a transcriptional reprogramming of neutrophils, characterized by the induction of thousands of proinflammatory genes, similarly to that promoted by R848. Furthermore, by using CU-CPT9a, a TLR8-specific inhibitor, we found that SCV2-RNA2 stimulates neutrophils exclusively via TLR8-dependent pathways. In sum, our study proves that single-strand RNAs from the SARS-CoV-2 genome potently activate human neutrophils via TLR8, thus uncovering a potential mechanism whereby neutrophils may contribute to the pathogenesis of severe COVID-19 disease.
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.