Targeted regulation of neutrophils is an effective approach for treating neutrophil-driven inflammatory diseases, but challenges remain in minimizing off-target effects and extending drug half-life. A DNA-based nanorobot was developed to target neutrophils by using an N-acetyl Pro-Gly-Pro (Ac-PGP) peptide to specifically bind to the C-X-C motif of chemokine receptor 2 (CXCR2) on neutrophil membranes. This robot (a tetrahedral framework nucleic acid modified with Ac-PGP, APT) identified and hitchhiked neutrophils to accumulate at inflammatory sites and prolong its half-lives, whilst also was internalized to influence the neutrophil cell cycle and maturation process to regulate oxidative stress, inflammation, migration, and recruitment in both in vivo and in vitro inflammation experiments. Consequently, the tissue damage caused by sepsis was greatly reduced. This novel neutrophil-based nanorobot highlights the high precision of targeting and regulating neutrophils, and presents a potential strategy for treating multiple neutrophil-driven diseases.

Noninvasive prognostic biomarkers to inform clinical decision-making are an urgent unmet need for the management of patients with glioblastoma (GBM). We previously showed that higher circulating cell-free DNA (ccfDNA) concentration is associated with worse survival in GBM. However, the biology underlying this is unknown.

We prospectively enrolled 129 patients with treatment-naïve GBM with blood drawn prior to initial resection (baseline) and at the time of the first postradiotherapy MRI. We performed ccfDNA methylation deconvolution to determine cellular sources of ccfDNA. ELISA was performed to detect citrullinated histone 3 (citH3), a marker of neutrophil extracellular traps (NET). Multiplex proteomic analysis was used to measure soluble inflammatory proteins.

We found that neutrophils contributed the highest proportion of prognostic ccfDNA. The percentage of ccfDNA derived from neutrophils was correlated with total [ccfDNA] but only in patients receiving preoperative corticosteroids. At baseline and on therapy, [citH3] was significantly higher in the plasma of patients with GBM receiving corticosteroids compared with corticosteroid-naïve GBM or no-cancer controls. Unsupervised hierarchical clustering of ccfDNA methylation patterns yielded two clusters, with one enriched for patients with the NETosis phenotype and who received corticosteroids. Unsupervised clustering of circulating inflammatory proteins yielded similar results.

These data suggest neutrophil-mediated NETosis is the dominant source of prognostic ccfDNA in patients with GBM and may be associated with glucocorticoid exposure. If further studies show that pharmacological inhibition of NETosis can mitigate the deleterious effects of corticosteroids, these plasma markers will have important clinical utility as noninvasive correlative biomarkers.

Bongkrekic acid (BKA), a less well-known foodborne toxin, has been implicated in numerous poisoning incidents. Recent studies suggest that BKA exerts an impact on the immune system, particularly on innate immunity. The release of neutrophil extracellular traps (NETs) is relatively a newly-discovered mechanism involving innate immunity. This study was designed to characterize and evaluate the effects of BKA on human NET formation. The co-localization of DNA, histones, and myeloperoxidase (MPO) was determined via immunostaining to confirm BKA-triggered NET formation in human neutrophils. NET quantification showed that NET formation induced by BKA was both time- and dose-dependent, and was associated with p38, ERK, PAD4 and P2X1 receptor. Moreover, immunostaining analysis observed that BKA triggered both NET formation and autophagy. Additionally, pharmacological experiments revealed that autophagy mediated BKA-triggered NET formation. Collectively, these insights offer a novel perspective on the effects of BKA exposure on host's innate immune response, and may shed new light on BKA poisoning. We call for further work to be conducted in this field to unravel the intricate mechanisms governing NET formation and autophagy in the context of BKA poisoning.

Since their discovery in 2004, neutrophil extracellular traps (NETs) have been at the center of multidisciplinary attention. Although a key tool in neutrophil-mediated immunity, these filamentous, enzyme-enriched DNA-histone complexes can be detrimental to tissues and have been identified as an underlying factor in a range of pathological conditions. Building on more than 20 years of research into NETs, this review places thrombosis, the pathological formation of blood clots, in the spotlight. From this point of view, we discuss the structure and formation of NETs, as well as the interaction of their components with the hemostatic system, dissecting the pathways through which NETs exert their marked effect on formation and the dissolution of thrombi. We pay distinct attention to the latest developments in the research of a key player in NET formation, peptidyl-arginine-deiminase (PAD) enzymes: their types, sources, and potential cross-play with the hemostatic machinery. Besides these molecular details, we elaborate on the link between pathological thrombosis, NETs, and widespread conditions that represent a debilitating public health burden worldwide, such as sepsis and neoplasms. Finally, future implications on the treatment of thrombosis-related conditions will be discussed.

Bacterial infections, especially drug-resistant bacterial infections, are causing increasing harm in clinical practice, and there is an urgent need to develop effective antimicrobial materials. Biomimetic DNA nanomachines have attracted much attention due to their flexible design, precise control, and high biocompatibility, but their use for bacterial inhibition has not been reported. Neutrophil extracellular traps (NETs), a network structure released by neutrophils with good bactericidal function, can be used as a superior biomimetic object for the construction of functional bacterial inhibition materials. In this study, Y-shaped DNA was polymerized using magnesium ions to develop reticulated DNA structures, which were used as templates to synthesize copper nanoclusters, leading to the construction of compositionally well-defined and simple reticulated DNA nanomachines. The nanomachine had a three-dimensional, reticular structure similar to that of NETs and especially had excellent antibacterial activity. More importantly, the NETs-imitated nanomachine had a multimodal bacterial inhibition mechanism. The nanomachine could target and localize around the bacteria and eliminate the biofilm, and then the DNA network structure effectively trapped and aggregated the bacteria and caused damage to the bacterial morphology and membrane structure; at the same time, the reticulated DNA nanomachine could also damage the bacterial membrane, causing the degradation and leakage of the proteins and the cellular contents and breakage of the DNA structure, ultimately causing irreversible inhibition of the bacteria. Importantly, the developed nanomachines with high biocompatibility could be used as antimicrobial biomaterials for the efficient treatment and healing of skin wounds infected with bacteria. This study develops a biomimetic DNA nanomachine that can be an excellent antibacterial biomaterial, which expands the application of DNA nanomachine in bacteriostatic and therapeutic fields; it is also an improved biomimetic NETs biomaterial, which brings distinctive design sources for biomimetic materials.

Diabetic retinopathy (DR) is a major cause of blindness globally. Neutrophils and neutrophil extracellular traps (NETs) are believed to play a role in the development of DR. However, the specific contribution of NETs to hyperglycemia-induced vascular endothelial cell dysfunction remains unclear. In this study, we cocultured high glucose-activated neutrophils (HGNs) with human umbilical vein endothelial cells (HUVECs) to investigate the role of NETs in high glucose-induced HUVEC dysfunction. Our findings indicate that high glucose levels promote NETs formation, which can be inhibited by a toll-like receptor (TLR) 2 antagonist and a TLR4 antagonist. It was observed that reactive oxygen species production plays a role in TLR2- but not TLR4-mediated NETs formation. Additionally, HGNs were found to promote HUVEC proliferation through phagocytosis rather than NETs. We also discovered that NETs contribute to high glucose-induced HUVEC dysfunction by enhancing neutrophil-HUVEC adhesion, inhibiting HUVEC migration, and compromising the barrier function of the cells by reducing zonula occludens-1 expression. This dysfunction could be partially mitigated by TLR2 and TLR4 antagonists. In conclusion, high glucose stimulates NETs formation, leading to vascular endothelial cell damage, and TLRs may facilitate high glucose-induced endothelial dysfunction by modulating NETs formation.

Patients with systemic lupus erythematosus (SLE) face an approximately 30 % risk of thrombosis post-diagnosis. However, there remains significant knowledge gaps regarding causative mechanisms, and there is a lack of specific antithrombotic guidelines. This systematic review aims to examine the existing literature regarding the mechanisms contributing to thrombosis risk in SLE, focusing on five predefined procoagulant domains: autoantibodies (including antiphospholipid antibodies (aPL)), the complement system, platelets, the endothelium, and the coagulation system. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statements and searched in PubMed and Embase without time restrictions. Risk of bias assessment was performed using a pre-specified evaluation tool. Out of 3,747 initially identified publications, 30 studies were included, with 28 demonstrating robust methodological quality in the risk of bias assessment. The studies were experimental, involving blood samples from cross-sectional SLE cohorts, except one animal -and one case-control study. We identified six different thrombosis mechanisms of action. Most studies concentrated on autoantibodies, predominantly aPL. Shared mechanisms between aPL and other autoantibodies may account for the increased thrombosis risk in aPL-negative SLE patients. Significant knowledge gaps remain, particularly regarding the role of the complement system in SLE-related thrombosis. Also, most research relies on cross-sectional designs, emphasizing the need for prospective cohort studies to better assess clinical factors. Finally, comprehensive studies examining the interactions between multiple procoagulant factors and their link to thrombosis are lacking. Closing these gaps in future research could improve both preventive and personalized treatment strategies for thrombosis in SLE.

Atherosclerosis (AS) is a disease characterised by the accumulation of atherosclerotic plaques on the inner walls of blood vessels, resulting in their narrowing. In its early stages, atherosclerosis remains asymptomatic and undetectable by conventional pathological methods. However, as the disease progresses, it can lead to a series of cardiovascular diseases, which are a leading cause of mortality among middle-aged and elderly populations worldwide. Neutrophil extracellular traps (NETs) are composed of chromatin and granular proteins released by neutrophils. Upon activation by external stimuli, neutrophils undergo a series of reactions, resulting in the release of NETs and subsequent cell death, a process termed NETosis. Research has demonstrated that NETosis is a means by which neutrophils contribute to immune responses. However, studies on neutrophil extracellular traps have identified NETs as the primary cause of various inflammation-induced diseases, including cystic fibrosis, systemic lupus erythematosus, and rheumatoid arthritis. Consequently, the present review will concentrate on the impact of neutrophil extracellular traps on atherosclerosis formation, analysing it from a molecular biology perspective. This will involve a systematic dissection of their proteomic components and signal pathways.

Sepsis, a life-threatening condition characterized by systemic inflammation and multiorgan dysfunction, is closely associated with the excessive formation of neutrophil extracellular traps (NETs) and the release of cell-free DNA. Both play a central role in sepsis progression, acting as major contributors to immunothrombosis and associated complications. Endogenous DNases play a pivotal role in degrading NETs and cell-free DNA, yet their activity is often dysregulated during thrombotic disease. Although exogenous DNase1 administration has shown potential in reducing NET burden and mitigating the detrimental effects of immunothrombosis, its therapeutic efficacy upon intravenous administration remains uncertain. The development of engineered DNase formulations and combination therapies may further enhance its therapeutic effectiveness by modifying its pharmacodynamic properties and avoiding the adverse effects associated with NET degradation, respectively. Although NETs are well-established targets of DNase1, it remains uncertain whether the positive effects of DNase1 on immunothrombosis are exclusively related to it's targeting of NETs or if other components contributing to immunothrombosis are also affected. This review examines the endogenous regulation of NETs in circulation and the therapeutic potential of DNases in immunothrombosis, underscoring the necessity for further investigation to optimize their clinical application.

Most early studies investigating the role of C-reactive protein (CRP) in tissue damage determined it supported pro-hemostatic and pro-inflammatory activities. However, these findings were not universal, as other data suggested CRP inhibited these same processes. A potential explanation for these disparate observations finally emerged with the recognition that CRP undergoes context-dependent conformational changes in vivo, and each of its three isoforms - pentameric CRP (pCRP), modified pentameric CRP (pCRP*), and monomeric CRP (mCRP) - have different effects. In this review, we consider this new paradigm and re-evaluate the role of CRP and its isoforms in the tissue repair process. Indeed, a growing body of evidence points toward the involvement of CRP not just in hemostasis and inflammation, but also in the resolution of inflammation and in tissue regeneration. Additionally, we briefly discuss the shortcomings of the currently available diagnostic tests for CRP and highlight the need for change in how CRP is currently utilized in clinical practice.

Neutrophils play a key role in inflammatory responses and thrombosis, but their complex interactions in disease pathogenesis are not fully understood. This review examines the multifaceted roles of neutrophils, focusing on their activation, cytokine release, and formation of neutrophil extracellular traps (NETs), which contribute to host defense and thrombosis. We discuss the interaction between inflammation and coagulation, the direct effect of neutrophils on thrombus stability, and their involvement in pathological thrombotic diseases. The therapeutic potential of neutrophil drug loading in the treatment of thrombosis, as well as the clinical implications and future research directions, are highlighted. The aim of this review is to gain insight into the critical neutrophil-inflammation-thrombus axis and its potential as a therapeutic target for thrombotic diseases and to suggest possible directions for neutrophil-loaded drug therapy for thrombosis.

Neutrophil extracellular traps (NETs) have received significant attention in recent years for their role in both the immune response and the vascular damage associated with inflammation. Platelets have been described as critical components of NETs since the initial description of this physio-pathological response of neutrophils. Platelets have been shown to play a dual role as responders and also as stimulators of NETs. The direct interaction with DNA leads to the entrapment of platelets into NETs, a phenomenon that significantly contributes to the thrombotic complications of inflammation and neutrophil activation, while the direct and paracrine stimulation of neutrophils by platelets has been shown to initiate the process of NET formation. In this review, we provide a comprehensive description of our current understanding of the molecular mechanisms underlying the entrapping of platelets into NETs and, in parallel, the platelet-driven cellular responses promoting NET formation. We then illustrate established examples of the contribution of NETs to vascular pathologies, describe the important questions that remain to be answered regarding the contribution of platelets to NET formation and NET-dependent cardiovascular complication, and highlight the fundamental steps taken towards the application of our understanding of platelets' contribution to NETs for the development of novel cardiovascular therapies.

This narrative review aims to describe the epidemiology and aetiologies of thrombocytopenia in critically ill patients, the bleeding risk assessment in thrombocytopenic patients, and provide an update on platelet transfusion indications.

Thrombocytopenia is a common disorder in critically ill patients. The classic definition relies on an absolute platelet count below 150 × 109/L. Alternatively, the definition has extended to a relative decrease in platelet count (typically within a range of >30->50% decrease) from baseline, yet remaining above 150 × 109/L. Thrombocytopenia may result from multiple mechanisms depending upon the underlying conditions and the current clinical setting. Regardless of the causes, thrombocytopenia accounts as an independent determinant of poor outcomes in critically ill patients, albeit often of unclear interpretation. Nevertheless, it is well established that thrombocytopenia is associated with an increased incidence of bleeding complications. However, alternative factors also contribute to the risk of bleeding, making it difficult to establish definite links between nadir platelet counts at the expense of potential adverse events. Platelet transfusion represents the primary supportive treatment of thrombocytopenia to prevent or treat bleeding. As randomised controlled trials comparing different platelet count thresholds for prophylactic platelet transfusion in the ICU are lacking, the prophylactic transfusion strategy is largely derived from studies performed in stable haematology patients. Similarly, the platelet count transfusion threshold to secure invasive procedures remains based on a low level of evidence. Indications of platelet transfusions for the treatment of severe bleeding in thrombocytopenic patients remain largely empirical, with platelet count thresholds ranging from 50 to 100 × 109/L. In addition, early and aggressive platelet transfusion is part of massive transfusion protocols in the setting of severe trauma-related haemorrhage.

Thrombocytopenia in critically ill patients is very frequent with various etiologies, and is associated with worsened prognosis, with or without bleeding complications. Interventional trials focused on critically ill patients are eagerly needed to better delineate the benefits and harms of platelet transfusions.

Neutrophil extracellular traps (NETs) are associated with diseases linked to aberrant coagulation. The blood clotting cascade involves a series of proteases, some of which induce NET formation via a yet unknown mechanism. We hypothesized that this formation involves signaling via a factor Xa (FXa) activation of the protease-activated receptor 2 (PAR2). Our findings revealed that NETs can be triggered in vitro by enzymatically active proteases and PAR2 agonists. Intravital microscopy of the liver vasculature revealed that both FXa infusion and activation of endogenous FX promoted NET formation, effects that were prevented by the FXa inhibitor, apixaban. Unlike classical NETs, these protease-induced NETs lacked bactericidal activity and their proteomic signature indicates their role in inflammatory disorders, including autoimmune diseases and carcinogenesis. Our findings suggest a novel mechanism of NET formation under aseptic conditions, potentially contributing to a self-amplifying clotting and NET formation cycle. This mechanism may underlie the pathogenesis of disseminated intravascular coagulation and other aseptic conditions.

This case report describes NETosis as a cause of thrombosis in an 18.3 kg, 8-year-old intact male mixed-breed dog with bacterial vasculitis. The dog presented with sudden paresis of the thoracic limb, characterized by cyanosis, absent arterial pulse, and decreased peripheral blood glucose levels. Doppler ultrasound confirmed thrombosis in the dorsal common digital artery. Histopathology post-amputation revealed bacterial vasculitis, thrombosis, and infarction, with immunohistochemical staining identifying extracellular citrullinated histone H3 (CitH3), indicative of NETs involvement. Treatment included antibiotics, pentoxifylline, and anticoagulants, showing transient improvement before disease progression and euthanasia due to respiratory signs. These findings suggest NETs as a potential therapeutic target for bacterial vasculitis in similar cases.

Platelets, traditionally known for their role in hemostasis, have emerged as key players in immune response and inflammation. Sepsis, a life-threatening condition characterized by systemic inflammation, often presents with thrombocytopenia, which at times, can be significant. Platelets contribute to the inflammatory response by interacting with leukocytes, endothelial cells, and the innate immune system. However, excessive platelet activation and consumption can lead to thrombocytopenia and exacerbate the severity of sepsis. Understanding the multifaceted roles of platelets in sepsis is crucial for developing effective therapeutic strategies. Targeting platelet-mediated inflammatory responses and promoting platelet production may offer potential avenues for improving outcomes in septic patients with thrombocytopenia. Future research should focus on elucidating the mechanisms underlying platelet dysfunction in sepsis and exploring novel therapeutic approaches to optimize platelet function and mitigate inflammation. This review explores the intricate relationship between platelets, inflammation, and thrombosis in the context of sepsis.

Neutrophil extracellular traps (NETs) participate in both host defense and the pathogenesis of various diseases, such as infections, thrombosis, and tumors. While they help capture and eliminate pathogens, NETs' excessive or dysregulated formation can lead to tissue damage and disease progression. Therapeutic strategies targeting NET modulation have shown potential, but challenges remain, particularly in achieving precise drug delivery and maintaining drug stability. Nanoparticle (NP)-based drug delivery systems offer innovative solutions for overcoming the limitations of conventional therapies. This review explores the biological mechanisms of NET formation, their interactions with NPs, and the therapeutic applications of NP-based drug delivery systems for modulating NETs. We discuss how NPs can be designed to either promote or inhibit NET formation and provide a comprehensive analysis of their potential in treating NET-related diseases. Additionally, we address the current challenges and future prospects for NP-based therapies in NET research, aiming to bridge the gap between nanotechnology and NET modulation for the development of novel therapeutic approaches.

Neutrophils release neutrophil extracellular traps (NETs) as part of a healthy host immune response. NETs physically trap and kill pathogens as well as activating and facilitating crosstalk between immune cells and complement. Excessive or inadequately resolved NETs are implicated in the underlying pathophysiology of sepsis and other inflammatory diseases, including amplification of the inflammatory response and inducing thrombotic complications. Here, we review the growing evidence implicating neutrophils and NETs as central players in the dysregulated host immune response. We discuss potential strategies for modifying NETs to improve patient outcomes and the need for careful patient selection.

Neutrophil extracellular trap (NET) is released by neutrophils to trap invading pathogens and can lead to dysregulation of immune responses and disease pathogenesis. However, systematic evaluation of NET-related genes (NETRGs) for the diagnosis of pediatric sepsis is still lacking. Three datasets were taken from the Gene Expression Omnibus (GEO) database: GSE13904, GSE26378, and GSE26440. After NETRGs and differentially expressed genes (DEGs) were identified in the GSE26378 dataset, crucial genes were identified by using LASSO regression analysis and random forest analysis on the genes that overlapped in both DEGs and NETRGs. These crucial genes were then employed to build a diagnostic model. The diagnostic model's effectiveness in identifying pediatric sepsis across the three datasets was confirmed through receiver operating characteristic curve (ROC) analysis. In addition, clinical pediatric sepsis samples were collected to measure the expression levels of important genes and evaluate the diagnostic model's performance using qRT-PCR in identifying pediatric sepsis in actual clinical samples. Next, using the CIBERSORT database, the relationship between invading immune cells and diagnostic markers was investigated in more detail. Lastly, to evaluate NET formation, we measured myeloperoxidase (MPO)-DNA complex levels using ELISA. A group of five important genes (MME, BST1, S100A12, FCAR, and ALPL) were found among the 13 DEGs associated with NET formation and used to create a diagnostic model for pediatric sepsis. Across all three cohorts, the sepsis group had consistently elevated expression levels of these five critical genes as compared to the normal group. Area under the curve (AUC) values of 1, 0.932, and 0.966 indicate that the diagnostic model performed exceptionally well in terms of diagnosis. Notably, when applied to the clinical samples, the diagnostic model also showed good diagnostic capacity with an AUC of 0.898, outperforming the effectiveness of traditional inflammatory markers such as PCT, CRP, WBC, and NEU%. Lastly, we discovered that children with high ratings for sepsis also had higher MPO-DNA complex levels. In conclusion, the creation and verification of a five-NETRGs diagnostic model for pediatric sepsis performs better than established markers of inflammation.

The increasing aging population and aging-associated diseases have become a global issue for decades. People over 65 show an increased prevalence and greater severity of periodontitis, which poses threats to overall health. Studies have demonstrated a significant association between aging and the dysfunction of neutrophils, critical cells in the early stages of periodontitis, and their crosstalk with macrophages and T and B lymphocytes to establish the periodontal lesion. Neutrophils differentiate and mature in the bone marrow before entering the circulation; during an infection, they are recruited to infected tissues guided by the signal from chemokines and cytokines to eliminate invading pathogens. Neutrophils are crucial in maintaining a balanced response between host and microbes to prevent periodontal diseases in periodontal tissues. The impacts of aging on neutrophils' chemotaxis, anti-microbial function, cell activation, and lifespan result in impaired neutrophil functions and excessive neutrophil activation, which could influence periodontitis course. We summarize the roles of neutrophils in periodontal diseases and the aging-related impacts on neutrophil functional responses. We also explore the underlying mechanisms that can contribute to periodontitis manifestation in aging. This review could help us better understand the pathogenesis of periodontitis, which could offer novel therapeutic targets for periodontitis.

Neutrophils are peripheral blood-circulating leukocytes that play a pivotal role in host defense against bacterial pathogens which upon activation, they release web-like chromatin structures called neutrophil extracellular traps (NETs). Here, we analyzed and compared the importance of myeloid differentiation factor 88 (MYD88), peptidyl arginine deiminase 4 (PAD4), and gasdermin D (GSDMD) for NET formation in vivo following sepsis and neutrophilia challenge. Injection of lipopolysaccharide (LPS)/E. coli or the transgenic expression of granulocyte colony-stimulating factor (G-CSF), each induced NET-mediated lethal vascular occlusions in mice with combined genetic deficiency in Dnase1 and Dnase1l3 (D1/D1l3-/-). In accordance with the signaling of toll-like receptors, Myd88/D1/D1l3-/- animals were protected from the formation of lethal intravascular NETs during septic conditions. However, this protection was not observed during neutrophilia. It was unexpected to find that both Gsdmd/D1/D1l3-/- and Pad4/D1/D1l3-/- mice were fully capable of forming NETs upon LPS/E.coli challenge. Sepsis equally triggered a similar inflammatory response in these mice characterized by formation of DNA-rich thrombi, vessel occlusions, and mortality from pulmonary embolism, compared to D1/D1l3-/- mice. Pharmacologic GSDMD inhibitors did not reduce PMA-stimulated NET formation in ex vivo models either. Similarly, neither Pad4 nor GSDMD deficiency affected intravascular occlusive NET formation upon neutrophilia challenge. The magnitude of NET production, multi-organ damage, and lethality were comparable to those observed in challenged control mice. In conclusion, our data indicate that NET formation during experimental sepsis and neutrophilia is regulated by distinct stimulus-dependent pathways that may be independent of canonical PAD4 and GSDMD.

The global pandemic of obesity poses a serious health, social, and economic burden. Patients living with obesity are at an increased risk of developing noncommunicable diseases or to die prematurely. Obesity is a state of chronic low-grade inflammation. Neutrophils are first to be recruited to sites of inflammation, where they contribute to host defense via phagocytosis, degranulation, and extrusion of neutrophil extracellular traps (NETs). NETs are web-like DNA structures of nuclear or mitochondrial DNA associated with cytosolic antimicrobial proteins. The primary function of NETosis is preventing the dissemination of pathogens. However, neutrophils may occasionally misidentify host molecules as danger-associated molecular patterns, triggering NET formation. This can lead to further recruitment of neutrophils, resulting in propagation and a vicious cycle of persistent systemic inflammation. This scenario may occur when neutrophils infiltrate expanded obese adipose tissue. Thus, NETosis is implicated in the pathophysiology of autoimmune and metabolic disorders, including obesity. This review explores the role of NETosis in obesity and two obesity-associated conditions-hypertension and liver steatosis. With the rising prevalence of obesity driving research into its pathophysiology, particularly through diet-induced obesity models in rodents, we discuss insights gained from both human and animal studies. Additionally, we highlight the potential offered by rodent models and the opportunities presented by genetically modified mouse strains for advancing our understanding of obesity-related inflammation.

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by enhanced platelet destruction and impaired platelet production, due to a loss of immune tolerance that leads to targeting of platelets and megakaryocytes by glycoprotein-autoantibodies and/or cytotoxic T cells. There is a high degree of heterogeneity in ITP patients signified by unpredictable disease trajectories and treatment responses. Initial studies in humans have identified intestinal microbiota perturbance in ITP. Recently, gut microbial perturbance has been linked to other autoimmune diseases. Based on these findings, we hypothesize that intestinal microbiota may influence ITP pathophysiology through several mechanisms, including induction of platelet-autoantibody production, increasing complement-dependent platelet cytotoxicity, disturbing T cell homeostasis, impairing megakaryocyte function, and increasing platelet-desialylation and -clearance. The pathophysiological heterogeneity of ITP may, at least in part, be attributed to a perturbed intestinal microbiota. Therefore, a better understanding of intestinal microbiota in ITP may result in a more personalized therapeutic approach.

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is the main cause of hospitalization and death of patients with chronic obstructive pulmonary disease. This is largely due to bacterial resistance caused by clinical antibiotic abuse and the limited efficacy of current treatment strategies in managing noninfectious AECOPD, which presents a significant challenge for clinicians. Therefore, it is urgent for clinical treatment and prevention of AECOPD to fully understand the specific mechanism of AECOPD in the immune system and master the key differences between infectious factors and noninfectious factors. This article systematically discusses AECOPD triggered by various factors, including the activation of immune system, the recruitment and activation of inflammatory cells and the role of specific inflammatory responses, and through a comprehensive review of the literature, this article expounds the existing targeted diagnosis and treatment methods and technologies at different stages in order to provide new ideas and strategies for clinical prevention and treatment of AECOPD.

 Thromboembolism is the second leading cause of death among patients with non-small cell lung cancer (NSCLC), but the precise mechanisms of thrombogenesis in NSCLC remain largely unknown. Our objectives were to evaluate the definitive role of neutrophil extracellular traps (NETs) in the hypercoagulability in NSCLC and to explore its interactions with platelets and endothelial cells (ECs).

 The levels of NET markers in samples from 100 NSCLC patients and 30 healthy controls were measured by ELISA. NET formation was detected using immunofluorescence. Procoagulant activity was assessed based on purified coagulation complex, thrombin, clotting time, and fibrin formation assays.

 The plasma levels of NETs were increased in a stage-dependent manner in NSCLC patients and were markedly higher than those in controls. Neutrophils from NSCLC patients were more prone to form NETs, resulting in shortened coagulation time, significantly increased thrombin-antithrombin complexes and fibrin compared to controls. Moreover, NETs generation was mediated by High Mobility Group Box 1 from activated platelets in NSCLC patients. Conversely, NETs from NSCLC patients also induce phosphatidylserine exposure on platelets, leading to markedly enhanced procoagulant activity (PCA). Furthermore, NETs can damage endothelial cells and convert them to a procoagulant phenotype. The administration of NETs inhibitors (DNase I/activated protein C) could markedly diminish the PCA of NETs, activated platelets, and ECs.

 Our results suggest that NETs contribute to hypercoagulability and may represent a potential therapeutic target to prevent cancer-associated thrombosis in NSCLC patients.

Although surgical resection of tumor mass remains the mainstay of curative therapeutic management for solid tumors, accumulating studies suggest that these procedures promote tumor recurrence and metastasis. Regarded as the first immune cells to fight against infectious or inflammatory insults from surgery, neutrophils along with their ability of neutrophil extracellular traps (NETs) production has attracted much attention. A growing body of evidence suggests that NETs promote cancer metastasis by stimulating various stages, including local invasion, colonization, and growth. Therefore, we discussed the mechanism of NETosis induced by surgical stress and tumor cells, and the contribution of NETs on tumor metastasis: aid in the tumor cell migration and proliferation, evasion of immune surveillance, circulating tumor cell adhesion and establishment of a metastatic niche. Lastly, we summarized existing NET-targeting interventions, offering recent insights into potential targets for clinical intervention.

SARS-CoV-2 3C-like protease (3CLpro or Mpro) cleaves the SARS-CoV-2 polyprotein and >300 intracellular host proteins to enhance viral replication. By lytic cell death following gasdermin (GSDM) pore formation in cell membranes, antiviral pyroptosis decreases 3CLpro expression and viral replication. Unexpectedly, 3CLpro and nucleocapsid proteins undergo unconventional secretion from infected cells via caspase-activated GSDMD/E pores in the absence of cell lysis. Bronchoalveolar lavage fluid of wild-type SARS-CoV-2-infected mice contains 3CLpro, which decreases in Gsdmd-/-Gsdme-/- mice. We identify new 3CLpro cut-sites in GSDMD at LQ29↓30SS, which blocks pore formation by 3CLpro cleavage at LH270↓N lying adjacent to the caspase activation site (NFLTD275↓G). Cleavage inactivation of GSDMD prevents excessive pore formation, thus countering antiviral pyroptosis and increasing 3CLpro secretion. Extracellular 3CLpro retains activity in serum, dampens platelet activation and aggregation, and inactivates antiviral interferon-λ1. Thus, in countering gasdermin pore formation and pyroptosis in SARS-CoV-2 infection, 3CLpro is secreted with extracellular pathological sequelae.

Neutrophil extracellular traps (NETs), an important host defense mechanism, are assembled after the release of decondensed chromatin and other nuclear components by a process termed NETosis. However, excessive NET release destroys surrounding tissues, leading to conditions such as sepsis where platelets are implicated in the pathogenic switch of NETosis. Here, we show that platelets trigger iron accumulation and promote lipid peroxide production in neutrophils co-stimulated with lipopolysaccharide and platelets in vitro, resulting in the induction of NETosis. We also screened for compounds that inhibit lipid peroxidation, identified 8-methyl-N-geranyl-6-nonamide (capsaicin), and assessed its potential in suppressing platelet-mediated pathogenic NETosis. Capsaicin inhibited lipopolysaccharide/platelet-induced cellular lipid peroxidation and suppressed NETosis in vitro. Furthermore, capsaicin attenuated NETosis in a mouse model of lipopolysaccharide-induced lung inflammation. Our findings provide an original therapeutic strategy to target lipid peroxidation and pave the way for drug development for a wide range of NETosis-related diseases.

Neutrophils are the most abundant cell type in the airways of tuberculosis patients. Mycobacterium tuberculosis (Mtb) infection induces the release of neutrophil extracellular traps (NETs); however, the molecular regulation and impact of NET release on Mtb pathogenesis are unknown. We find that during Mtb infection in neutrophils, PAD4 citrullinates histones to decondense chromatin that gets released as NETs in a manner that can maintain neutrophil viability and promote Mtb replication. Type I interferon promotes the formation of chromatin-containing vesicles that allow NET release without compromising plasma membrane integrity. Analysis of nonhuman primate granulomas supports a model where neutrophils are exposed to type I interferon from macrophages as they migrate into the granuloma, thereby enabling the release of NETs associated with necrosis and caseation. Our data reveal NET release as a promising target to inhibit Mtb pathogenesis.

Subarachnoid hemorrhage (SAH) can lead to acute or delayed cerebral ischemia. Recent findings have revealed that spasm of microvessels, called microvasospasm, may contribute to SAH-related cerebral ischemia, and perivascular inflammation is considered important in the development of microvasospasms. However, owing to the difficulty in investigating the dynamics of vascular and perivascular events, little is known about the mechanisms underlying microvasospasms.

We established an experimental system aiming to investigate the vascular and perivascular pathology of SAH by combining a SAH mouse model with intravital 2-photon imaging. SAH was induced by intracisternal blood injection, and the distribution of erythrocytes, neutrophil behavior, and morphological changes in the pial arterioles were analyzed over time by 2-photon microscopy imaging. To further explore the role of neutrophils and neutrophil extracellular traps (NETs) in microvasospasm, we performed neutrophil depletion by intraperitoneal administration of neutrophil-specific antibody or NETs removal by intracisternal administration of DNase.

Erythrocytes were immediately distributed in the perivascular space of the arterioles after SAH induction; neutrophils intensively infiltrated the perivascular space within 2 days and subsequently showed NETosis; and pial arterioles in the same region developed pearl-string-like microvasospasms in the subacute phase. Neutrophil depletion significantly reduced the number of microvasospasms. Furthermore, the removal of perivascular NETs drastically reduced microvasospasms.

By establishing a unique experimental system, we demonstrated that perivascular NETs could be a new therapeutic target for microvasospasms.

Neutrophil extracellular traps (NETs) represent a response mechanism in which activated neutrophils release DNA-based webs, adorned with histones and neutrophil proteases, to capture and eliminate invasive microorganisms. However, when these neutrophils become excessively activated, much more proteases associated with NETs are liberated into surrounding tissues or bloodstreams, thereby altering the cellular milieu and causing tissue damage. Recent research has revealed that NETs may play significant roles in the emergence and progression of various diseases, spanning from infections, inflammation to autoimmune disorders and cancers. In this review, we delve deeply into the intricate and complex mechanisms that underlie the formation of NETs and their profound interplay with various clinical pathologies. We aim to describe the application perspectives of NETs related proteins in specific disease diagnosis and treatment.

Many virus types affect the blood clotting system with correlations to pathology that range widely from thrombosis to hemorrhage linking to inflammation. Here we overview the intricate crosstalk induced by infection between proteins on the virus encoded by either the host or virus genomes, coagulation proteins, platelets, leukocytes, and endothelial cells. For blood-borne viruses with an outer covering acquired from the host cell, the envelope, a key player may be the cell-derived trigger of coagulation on the virus surface, tissue factor (TF). TF is a multifunctional transmembrane cofactor that accelerates factor (F)VIIa-dependent activation of FX to FXa, leading to clot formation. However, the nascent TF/FVIIa/FXa complex also facilitates G protein-coupled modulation of cells via protease-activated receptor 2. As a viral envelope constituent, TF can bypass the physiological modes of regulation, thereby initiating the activation of neighboring platelets, leukocytes, and endothelial cells. A thromboinflammatory environment is predicted due to feedback amplification in response to cellular release of cytokines, procoagulant proteins, neutrophil extracellular traps, and stimulus-induced accessibility of adhesive receptors, resulting in cellular aggregates. The pathobiological effects of thromboinflammation ultimately contribute to innate and adaptive immunity for viral clearance. In contrast, the preceding stages of viral infection may be enhanced via the TF-protease axis.

Platelets navigate the fine balance between homeostasis and injury. They regulate vascular homeostasis and drive repair after injury amidst leukocyte extravasation. Crucially, platelets initiate extracellular traps generation and promote immunothrombosis. In chronic human diseases, platelet action often extends beyond its normative role, sparking sustained reciprocal activation of leukocytes and mural cells, culminating in adverse vascular remodeling. Studies in the last decade have spotlighted a novel key player in platelet activation, the high mobility group box 1 (HMGB1) protein. Despite its initial characterization as a chromatin molecule, anucleated platelets express abundant HMGB1, which has emerged as a linchpin in thromboinflammatory risks and microvascular remodeling. We propose that a comprehensive assessment of platelet HMGB1, spanning quantification of content, membrane localization, and accumulation of HMGB1-expressing vesicles in biological fluids should be integral to dissecting and quantifying platelet activation. This review provides evidence supporting this claim and underscores the significance of platelet HMGB1 as a biomarker in conditions associated with heightened thrombotic risks and systemic microvascular involvement, spanning cardiovascular, autoimmune, and infectious diseases.

The development of inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, involves various factors and is characterized by persistent inflammation of the mucosal lining. However, the role of neutrophils in this process remains controversial. Neutrophil extracellular traps (NETs), which consist of chromatin, antimicrobial proteins, and oxidative enzymes, are released by neutrophils to trap pathogens. They are also involved in various immune-mediated and vascular diseases. NETs act as a vital defense mechanisms at the gut-mucosal interface and are frequently exposed to bacterial, viral, and fungal threats. However, they can also contribute to inflammation and worsen imbalances in the gut bacteria. Recent studies have suggested that NETs have a significant impact on IBD development. Previous studies have shown increased levels of NETs in tissue and blood samples from patients with IBD, as well as in experimental colitis mouse models. Therefore, this review discusses how NETs are formed and their role in the pathophysiology of IBD. It discusses how NETs may lead to tissue damage and contribute to IBD-associated complications. Moreover, non-invasive biomarkers are needed to replace invasive procedures such as endoscopy to better evaluate the disease status. Given the crucial role of NETs in IBD progression, this review focuses on potential NET biomarkers that can help predict the evolution of IBD. Furthermore, this review identifies potential therapeutic targets for regulating NET production, which could expand the range of available treatment options for IBD.

The article characterises platelets, pointing out the role and contribution of their numerous receptors determining their specific and broad immune activity. Three types of platelet receptors are described, that is, extracellular and intracellular receptors-TLR (toll-like receptors), NLR (NOD-like receptor), and RLR (RIG-I-like receptor); extracellular receptors-selectins and integrins; and their other extracellular receptors-CLR (C-type lectin receptor), CD (cluster of differentiation), TNF (tumour necrosis factor), among others. Outlining the contribution of these numerous platelet receptors to the intravascular immunity, it has been shown that they are formed by their fusion with pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs), and lifestyle-associated molecular patterns (LAMPs). They are initiating and effector components of signal transduction of these cells, and their expression and quantity determine the specific and broad functions of platelets towards influencing vascular endothelial cells, but mainly PRRs (pattern recognition receptors) of blood immune cells. These facts make platelets the fundamental elements that shape not only intravascular homeostasis, as previously indicated, but they become the determinants of immunity in blood vessels. Describing the reactions of the characterised three groups of platelet receptors with PAMP, DAMP and LAMP molecules, the pathways and participation of platelets in the formation and construction of intravascular immune status, in physiological states, but mainly in pathological states, including bacterial and viral infections, are presented, making these cells essential elements in the health and disease of mammals, including humans.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus) has been a major cause of significant morbidity and mortality. Acute kidney injury (AKI) has been seen in COVID-19-infected subjects, and it has frequently resulted in an abnormal estimated glomerular filtration rate. Colchicine, an immunomodulatory drug, was used in several studies in the early stages of the pandemic. Colchicine has been shown to prevent the development of renal failure in patients with Familial Mediterranean Fever (FMF). It has also been reported to reduce fibrosis, which plays a role in chronic kidney disease. We, therefore, aimed to investigate whether using Colchicine, in addition to standard care, was associated with better renal function in patients with severe COVID-19 infection.

This retrospective cohort study comprised 118 out of 605 hospitalized COVID-19 subjects. Some of the subjects (n = 50) received oral Colchicine plus standard care, called the Col ( +) group. The others (n = 68) received only the standard care, called the Col (-) group. The estimated glomerular filtration rate (eGFR) and other laboratory findings, including lymphocytes, D-dimer, and CRP, were analyzed.

The D-dimer and serum creatine levels were significantly reduced in both groups. The number of lymphocytes showed a significant increase in both groups at discharge. The level of C-reactive protein (CRP) was significantly higher in the Col ( +) group than in the Col (-) group at admission. The reduction of SCr was considerably higher in the Col ( +) group than in the Col (-) group. Similarly, the improvement of eGFR was higher in the Col ( +) group than in the Col (-) group at discharge and 6-12 mounts follow-up.

Our findings indicated the use of Colchicine plus standard care was associated with improved renal function in hospitalized patients with severe COVID-19 infection.

Neutrophil extracellular traps (NETs) released by neutrophils are web-like DNA structures adhered to granulin proteins with bactericidal activity and can be an important mechanism for preventing pathogen dissemination or eliminating microorganisms. However, they also play important roles in diseases of other systems, such as the central nervous system. We tracked the latest advances and performed a review based on published original and review articles related to NETs and neurological diseases. Generally, neutrophils barely penetrate the blood-brain barrier into the brain parenchyma, but when pathological changes such as infection, trauma, or neurodegeneration occur, neutrophils rapidly infiltrate the central nervous system to exert their defensive effects. However, neutrophils may adversely affect the host when they uncontrollably release NETs upon persistent neuroinflammation. This review focused on recent advances in understanding the mechanisms and effects of NETs release in neurological diseases, and we also discuss the role of molecules that regulate NETs release in anticipation of clinical applications in neurological diseases.

CpG oligonucleotides (ODNs) are synthetic single-stranded DNA sequences that act as immunostimulants. They have been increasingly used to treat several cancers; however, thrombocytopenia is a potential recognized side effect of some sequences.

We tested the ability of 2 CpG ODNs (ODN 2395 and ISIS 120704) to induce thrombocytopenia when administered to BALB/c mice and determined mechanisms associated with thrombocytopenia.

BALB/c mice were prebled and then injected with titrated doses of CpG ODNs, and platelet counts were determined. The mice were treated with intravenous immunoglobulin (IVIg) or various inhibitors and antagonists of toll-like receptor 9 (TLR9) and spleen tyrosine kinase (Syk) to determine their effects on thrombocytopenia.

Compared with saline-treated mice or mice treated with 2'-O-methoxyethyl-modified antisense ODN, both ODN 2395 and ISIS 120704 induced acute dose-dependent thrombocytopenia within 3 and 24 hours, respectively. The thrombocytopenia was associated with significant increases in plasma monocyte chemoattractant protein 1. IVIg administration significantly rescued the CpG ODN-induced thrombocytopenia, as did treatment with either a Syk inhibitor or TLR9 antagonists. In vitro, CpG ODN could activate human platelets and this correlated significantly with enhanced IVIg- and Syk-dependent phagocytosis by THP-1 monocytes.

These results suggest that CpG ODNs induce acute inflammatory-associated (IVIg-sensitive) thrombocytopenia that can be alleviated by Syk- or TLR9-blockade, and an IVIg- and Syk-dependent platelet clearance pathway appears primarily responsible for the thrombocytopenia.

Sickle cell disease (SCD) is the most common inherited monogenetic disorder. Chronic and acute pain are hallmark features of SCD involving neural and vascular injury and inflammation. Mast cells reside in the vicinity of nerve fibers and vasculature, but how they influence these structures remains unknown. We therefore examined the mechanism of mast cell activation in a sickle microenvironment replete with cell-free heme and inflammation. Mast cells exposed to this environment showed an explosion of nuclear contents with the release of citrullinated histones, suggestive of mast cell extracellular trap (MCET) release. MCETs interacted directly with the vasculature and nerve fibers, a cause of vascular and neural injury in sickle cell mice. MCET formation was dependent upon peptidylarginine deiminase 4 (PAD4). Inhibition of PAD4 ameliorated vasoocclusion, chronic and acute hyperalgesia, and inflammation in sickle mice. PAD4 activation may also underlie neutrophil trap formation in SCD, thus providing a novel target to treat the sequelae of vascular and neural injury in SCD.

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus, SEZ) is an essential zoonotic bacterial pathogen that can cause various inflammation, such as meningitis, endocarditis, and pneumonia. UDP-glucose dehydrogenase (hasB) is indispensable in synthesizing SEZ virulence factor hyaluronan capsules. Our study investigated the infection of hasB on mice response to SEZ by employing a constructed capsule-deficient mutant strain designated as the ΔhasB strain. This deficiency was associated with a reduced SEZ bacterial load in the mice's blood and peritoneal lavage fluid (PLF) post-infection. Besides, the ΔhasB SEZ strain exhibited a higher propensity for neutrophil infiltration and release of cell-free DNA (cfDNA) in vivo compared to the wild-type (WT) SEZ strain. In vitro experiments further revealed that ΔhasB SEZ more effectively induced the formation of neutrophil extracellular traps (NETs) containing histone 3 (H3), neutrophil elastase (NE), and DNA, than its WT counterpart. Moreover, the release of NETs was determined to be gasdermin D (GSDMD)-dependent during the infection process. Taken together, these findings underscore that the deficiency of the hasB gene in SEZ leads to enhanced GSDMD-dependent NET release from neutrophils, thereby reducing SEZ's capacity to resist NETs-mediated eradication during infection. Our finding paves the way for the development of innovative therapeutic strategies against SEZ.