Acute liver failure (ALF) is an acute liver disease with a high mortality rate in clinical practice, characterized histologically by extensive hepatocellular necrosis and massive neutrophil infiltration. However, the role of these abnormally infiltrating neutrophils during ALF development is unclear. Here, in an ALF mouse model, metabolites were identified that promote the formation of neutrophil extracellular traps (NETs) in the liver, subsequently influencing macrophage differentiation and disease progression. ALF occurs with abnormalities in hepatic and intestinal metabolites. Abnormal metabolites (LTD4 and glutathione) can directly, or indirectly via reactive oxygen species, promote NET formation of infiltrating neutrophils, which subsequently regulate macrophages in a pro-inflammatory M1-like state, inducing an amplification of the destructive effects of inflammation. Together, this study provides new insights into the role of NETs in the pathogenesis of ALF.

Cardiovascular diseases (CVDs) continue to pose a significant burden on global health, prominently contributing to morbidity and mortality rates worldwide. Recent years have witnessed an increasing recognition of the intricate involvement of neutrophil extracellular traps (NETs) in the pathology of diverse cardiovascular conditions. This review provides a comprehensive analysis of the multifaceted functions of NETs in cardiovascular diseases, shedding light on the impact on atherosclerosis, myocardial infarction, heart failure, myocarditis, atrial fibrillation, aortic stenosis, and the potential therapeutic avenues targeting NETs.

During the inflammatory storm of sepsis, a significant quantity of neutrophil extracellular traps (NETs) are generated, which act as a double-edged sword and not only impede the invasion of foreign microorganisms but also exacerbate organ damage. This study provides evidence that NETs can cause damage to alveolar epithelial cells in vitro. The sepsis model developed in this study showed a significant increase in NETs in the bronchoalveolar lavage fluid (BALF). The development of NETs has been shown to increase the lung inflammatory response and aggravate injury to alveolar epithelial cells. Bay-117082, a well-known NF-κB suppressor, is used to modulate inflammation. This analysis revealed that Bay-117082 efficiently reduced total protein concentration, myeloperoxidase activity, and inflammatory cytokines in BALF. Moreover, Bay-117082 inhibited the formation of NETs, which in turn prevented the activation of the pore-forming protein gasdermin D (GSDMD). In summary, these results indicated that excessive NET production during sepsis exacerbated the onset and progression of acute lung injury (ALI). Therefore, Bay-117082 could serve as a novel therapeutic approach for ameliorating sepsis-associated ALI.

BACKGROUND: Acute lung injury (ALI) is a devastating condition caused by sepsis, pneumonia, trauma, and more recently, COVID-19. SH003, an herbal formula consisted of Astragalus membranaceus, Angelica gigas and Trichosanthes kirilowii, is known for its effects on cancer and immunoregulation.
OBJECTIVE: Previous studies show SH003 exerts a promising anti-inflammatory effect. This study investigates the effect of modified SH003 on ALI using in silico, in vivo, and in vitro models.
METHODS: We performed in silico-based analysis of SH003 on ALI-related pathways. C57BL/6 mice were intraperitoneally subjected to lipopolysaccharide (LPS) to induce septic ALI, followed by oral administration of SH003 for 2 weeks. Dexamethasone was used as the positive control. Human peripheral blood-derived polymorphonuclear neutrophils (PMN) were used to investigate the effect and mechanisms of SH003 on neutrophil extracellular trap (NET) formation.
RESULTS: Network pharmacology analysis suggested SH003 regulates lung inflammation by modulating NET formation. SH003 significantly reduced mortality in sepsis in vivo by inhibiting local and systemic inflammation, likely via nuclear factor kappa B and mitogen-activated protein kinase pathways-mediated inflammasome suppression. SH003 also decreased NET-related markers in lung tissues and inhibited LPS- and phorbol myristate acetate-induced NET formation in PMN. Cytometry time-of-flight analysis confirmed regulation of NETosis-related pathways by SH003.
CONCLUSIONS: SH003 effectively inhibits excessive immune responses in the lung by suppressing inflammasome activation and NET formation. These findings suggest SH003 as a potential therapeutic agent for septic ALI.

OBJECTIVE: During early phases of inflammation, activated neutrophils extrude neutrophil extracellular traps (NETs) in a PAD4-dependent manner, aggravating tissue injury and remodelling. In this study, we investigated the potential pro-fibrotic properties and signalling of NETs in Crohn\'s disease (CD).
METHODS: NETs and activated fibroblasts were labelled on resected ileum from CD patients by multiplex immunofluorescence staining. NETs-treated human primary intestinal fibroblasts were analysed by bulk RNA-sequencing to uncover cell signalling pathways, and by high-throughput imaging to assess collagen production and migratory activity. Consequentially, TLR2/NF-kB pathway was evaluated by transfection of CCD-18Co fibroblasts with NF-kB-luciferase reporter plasmid, incorporating C29 to block TLR2 signalling. A chronic DSS mouse model was used to define the specific role of PAD4 deletion in neutrophils (MRP8-Cre, Pad4fl/fl).
RESULTS: Immunofluorescence showed spatial co-localisation of NETs and activated fibroblasts in ileal ulcerations of CD patients. Transcriptomic analysis revealed upregulation of pro-fibrotic genes and activation of TLR-signalling pathways in NETs-treated fibroblasts. NETs treatment induced fibroblast proliferation, diminished migratory capability, and increased collagen release. Transfection experiments indicated a substantial increase in NF-kB expression with NETs, whereas C29 led to decreased expression and release of collagen. In line, a significantly reduction in collagen content was observed in the colon of MRP8-Cre, Pad4fl/fl mice subjected to chronic DSS colitis.
CONCLUSIONS: NETs potentially serve as an initial stimulus for pathological activation of fibroblasts within the intestine via the TLR2/NF-kB pathway. Given their early involvement in inflammation, inhibition of PAD4 might offer a strategy to modulate both inflammation and fibrogenesis in CD.

BACKGROUND: Acute gouty arthritis (AGA) is classified as \'arthritis\' in traditional Chinese medicine (TCM) theory. Shirebi granules (SGs), derived from the classic prescription SiMiaoWan, exerts satisfying therapeutic efficacy in ameliorating AGA clinically. However, the underlying mechanisms of SGs against AGA remain unclarified.
METHODS: AGA-related biological processes, signal pathways and biomarker genes were mined from the GEO database through bioinformatics. SGs components were systematically recognized using the UPLC-Q-TOF-MS/MS. A correlation network was established based on the biomarker genes and the chemical components, from which the signal pathway used for further study was selected. Finally, we established an AGA model using SD rats injected with monosodium urate (MSU) in the ankle joint for experimental validation. A combination of behavioral tests, H&E, safranin O- fast green, western blotting, and immunofluorescence were employed to reveal the mechanism of action of SGs on AGA.
RESULTS: The deterioration of AGA was significantly related to the imbalance between immunity and inflammation, neutrophil chemotaxis and inflammatory factor activation. HDAC5, PRKCB, NFκB1, MPO, PRKCA, PIK3CA were identified to be the candidate targets of SGs against AGA, associated with neutrophil extracellular traps (NETs) signal pathway. Animal experiments demonstrated that SGs effectively repaired cartilage damage, blocked TLR4 activation, and inhibited the expression of NETs indicators and inflammatory factors. In addition, SGs prominently alleviated joint redness and swelling, improved joint dysfunction, inhibited inflammatory infiltration of AGA rats.
CONCLUSIONS: Our data reveal that SGs may effectively alleviate the disease severity of AGA by suppressing NETs-promoted imbalance between immunity and inflammation.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease. Abnormal formation of neutrophil extracellular traps (NETs) at the synovial membrane leads to the release of many inflammatory cytokines, including IL-1β, IL-6, and TNF-α. Elastase, histone H3, and myeloperoxidase, which are carried by NETs, damage the soft tissues of the joints and aggravate the progression of RA. The balance of NET formation coordinates the pro-inflammatory and anti-inflammatory effects and plays a key role in the development of RA. Therefore, when NETs are used as effector targets, highly targeted drugs with fewer side effects can be developed to treat RA without damaging the host immune system. Currently, an increasing number of studies have shown that traditional Chinese medicines and natural products can regulate the formation of NETs through multiple pathways to counteract RA, which shows great potential for the treatment of RA and has a promising future for clinical application. In this article, we review the latest biological progress in understanding NET formation, the mechanism of NETs in RA, and the potential targets or pathways related to the modulation of NET formation by Chinese medicines and natural products. This review provides a relevant basis for the use of Chinese medicines and natural products as natural adjuvants in the treatment of RA.

Historically, neutrophils have been primarily regarded as short-lived immune cells that act as initial responders to antibacterial immunity by swiftly neutralizing pathogens and facilitating the activation of adaptive immunity. However, recent evidence indicates that their roles are considerably more complex than previously recognized. Neutrophils comprise distinct subpopulations and can interact with various immune cells, release granular proteins, and form neutrophil extracellular traps. These functions are increasingly recognized as contributing factors to tissue damage in autoimmune diseases. This review comprehensively examines the physiological functions and heterogeneity of neutrophils, their interactions with other immune cells, and their significance in autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid syndrome, antineutrophil cytoplasmic antibody-associated vasculitis, multiple sclerosis, and others. This review aims to provide a deeper understanding of the function of neutrophils in the development and progression of autoimmune disorders.

Neutrophil extracellular traps (NETs) are web-like structures composed of cytoplasmic contents, DNA chromatin and various granular proteins released by neutrophils in response to viruses, bacteria, immune complexes and cytokines. Studies have shown that NETs can promote the occurrence, development and metastasis of tumors. In this paper, the mechanism underlying the formation and degradation of NETs and the malignant biological behaviors of NETs, such as the promotion of tumor cell proliferation, epithelial mesenchymal transition, extracellular matrix remodeling, angiogenesis, immune evasion and tumor-related thrombosis, are described in detail. NETs are being increasingly studied as therapeutic targets for tumors. We have summarized strategies for targeting NETs or interfering with NET-cancer cell interactions and explored the potential application value of NETs as biomarkers in cancer diagnosis and treatment, as well as the relationship between NETs and therapeutic resistance.

OBJECTIVE: This review aims to identify biological markers associated with the risk of recurrence of thrombotic and/or obstetric events in patients with antiphospholipid syndrome (APS).
METHODS: A comprehensive review of literature was conducted to evaluate established and potential novel biological markers associated with thrombosis in APS. To this end, a PubMed literature search was conducted for the last twenty years using the following keywords or their combinations: thrombotic risk, recurrence of thrombosis, risk stratification, severity, predictive value.
RESULTS: Previous studies showed that multiple aPL positivity correlates with an increased risk of thrombosis in APS. Moreover, the analysis of N-glycosylation of antiphospholipid antibodies (aPL) revealed that low levels of IgG sialylation, fucosylation or galactosylation increases the pro-inflammatory activity of aPL, predisposing to thrombosis. In addition, quantification of neutrophil extracellular traps (NETs) and antibodies directed against NETs (anti-NETs) in serum demonstrates promising prognostic utility in assessing APS severity. Oxidative stress plays a role in the pathogenicity of APS and paraoxonase 1 (PON1) activity emerges as a promising biomarker of thrombotic risk in APS. Furthermore, identification of novel antigenic targets involved in the pathophysiology of APS, such as lysobisphosphatidic acid (LBPA), had led to the discovery of unconventional aPL, antibodies directed against the LBPA (aLBPA), whose clinical value could make it possible to identify APS patients at high risk of thrombotic recurrence.
CONCLUSIONS: The immunological profile of aPL, N-glycosylation of aPL, quantification of NETs and anti-NETs, analysis of biomarkers of oxidative stress and the discovery of aLBPA offer potential prognostic tools for risk stratification in APS patients.