Project description:Although the formation of neutrophil extracellular traps (NETs) is caused by inflammation-related factors, it remains unclear whether endogenous hormones promote NET formation. Here, we investigate NET formation between infection-driven inflammatory endometrium and estrogen-induced hyperplastic endometrium by single-cell multiomics analysis. We identified a unique neutrophil subpopulation (CD24high neutrophil) involved in estrogen-driven NET formation. Estrogen-induced NETs mainly form due to the imbalance of histone caused by estrogen receptors. Inhibition of NETs significantly ameliorated endometrial hyperplasia (EH) in a murine model. Mechanistically, NETs promote cell proliferation by binding to NKCC1 on epithelial cells. Aspirin was screened to inhibit NET formation and alleviated EH in cynomolgus monkey. This study provides a novel nonhormone replacement therapy to treat patients with estrogen abnormalities by targeting NETs.
Project description:Neutrophil extracellular traps (NETs) promote inflammation and atherosclerosis progression. In diabetes they are increased and impair wound healing, during which inflammation normally resolves. Atherosclerosis regression, a process resembling wound healing, is also impaired in diabetes. Thus, we hypothesized that NETs impede atherosclerosis regression in diabetes through unresolved inflammation. Objective: To investigate in diabetes the effect of NETs on plaque macrophage inflammation and whether NETs reduction improves atherosclerosis regression. Findings: Transcriptomic profiling of plaque macrophages from NET positive and negative areas in Ldlr-/- mice revealed inflammasome and glycolysis pathway upregulation, indicating a pro-inflammatory phenotype. During atherosclerosis regression in non-diabetic mice, plaque NET content decreased. In contrast, in diabetic mouse plaques NETs were enriched and persisted after lipid-lowering. DNase1 treatment (to degrade NETs) of diabetic mice reduced plaque NETs and macrophage inflammation and improved atherosclerosis regression after lipid-lowering. Conclusions: NETs decline during atherosclerosis regression in non-diabetic mice, but persist in diabetes and impair regression by exacerbating macrophage inflammation. DNase1 reduced diabetic plaque NETs and macrophage inflammation, and restored atherosclerosis resolution after lipid-lowering, despite ongoing hyperglycemia. Given that humans with diabetes also exhibit impaired atherosclerosis resolution with lipid-lowering, these data suggest that NETs contribute to the increased CVD risk in this population.
Project description:Neutrophils are necessary in mamalian’s life and are the most abundant type of white blood cells in humans with biological roles relevant to inflammation and the entire host response. The release of neutrophil extracellular DNA in innate immune cells provides specific response to bacteria and fungi. Neutrophil Extracellular Traps (NETs) act as antimicrobial agents and activators of immune response through release of the nuclear content into the extracellular space. Although great strides have been made in dissecting cellular and molecular pathways that control NET formation, the exact molecular composition of released NETs has not been elucidated. Here, we open the field of NETOMIC studies through isolation of NETs in combination with shotgun genomics and proteomics. This study reveals the molecular composition of NETs and specific expression regions of NETs induced in a sterile inflammation system. The existence of an in vitro NET isolation model allowed for an unprecedented amount of replicability. Additional studies are needed to verify the specificity of these sequences in the context of human health and disease upon diverse neutrophil microbial challenges.
Project description:Extracellular traps (NETs) are released by neutrophils during inflammation and play a role in pathology of diseases such as atherosclerosis, as well as their innate immune function of clearing infection. NETs are composed of a mesh of DNA and histones and contain various anti-microbial granule proteins, such as myeloperoxidase (MPO), which remains enzymatically active. This can result in the production of the reactive oxidant hypochlorous acid (HOCl), which reacts readily with proteins. However, whether histones and other NET-associated proteins contain HOCl-modified proteins is unknown. This is significant as recent studies show that exposure of histones to HOCl alters their extracellular reactivity to promote inflammatory signaling in vascular cells. In this study, we used a proteomic approach to characterise the protein composition of NETs and examine whether histones and other proteins contain oxidative protein-translational modifications resulting from reactions with HOCl. NETs were collected from neutrophil-like PLB-985 cells and primary neutrophils stimulated with phorbol myristate acetate (PMA) or nigericin, a bacterial peptide derived from Streptomyces hygroscopicus. Exposure of proteins to HOCl results in the formation of nitrile and aminoadipic semialdehyde formation on lysine residues, chlorination of tyrosine and tryptophan residues together with methionine oxidation products. Evidence was obtained for the presence of tyrosine chlorination on histones, particularly histone H4, and other proteins like quinone oxidoreductase. Other PTMs, including citrullination and acetylation were also detected on histones (H1, H2A, H3 and H4). Chlorination of the histone H4 peptide TVTAMDVVYALK(R) by HOCl was more abundant in NETs obtained from neutrophils exposed to PMA compared to nigericin, consistent with nigericin triggering NET release via a non-oxidative pathway. Current studies are investigating whether histone modifications occur before or after release from the cell. These findings provide the first evidence that HOCl induces histone modifications on NETs, which may be relevant in disease.
Project description:To investigate the altered gene expression levels in BMDMs treated with or without NETs. Each group had a biological repeat (n=3). Results provide insight into the effect of NETs on BMDMs.