Neutrophil extracellular traps mediate neuro-immunothrombosis

Neutrophil extracellular traps are primarily composed of DNA and histones and are released by neutrophils to promote inflammation and thrombosis when stimulated by various inflammato ry reactions.Neutrophil extracellular trap formation occurs through lytic and non-lytic pathways that can be further classified by formation mechanisms.Histones,von Willebrand factor,fibrin,and many other factors participate in the interplay between inflammation and thrombosis.Neuroimmunothrombosis summarizes the intricate interplay between inflammation and thrombosis during neural development and the pathogenesis of neurological diseases,providing cutting-edge insights into post-neurotrauma thrombotic events.The blood-brain barrier defends the brain and spinal cord against external assaults,and neutrophil extracellular trap involvement in blood-brain barrier disruption and immunothrombosis contributes substantially to secondary injuries in neurological diseases.Further research is needed to understand how neutrophil extracellular traps promote blood-brain barrier disruption and immunothrombosis,but recent studies have demonstrated that neutrophil extracellular traps play a crucial role in immunothrombosis,and identified modulators of neuro-immunothrombosis.However,these neurological diseases occur in blood vessels,and the mechanisms are unclear by which neutrophil extracellular traps penetrate the blood-brain barrier to participate in immunothrombosis in traumatic brain injury.This review discusses the role of neutrophil extracellular traps in neuro-immunothrombosis and explores potential therapeutic interventions to modulate neutrophil extracellular traps that may reduce immunothrombosis and improve traumatic brain injury outcomes.

Wrecking neutrophil extracellular traps and antagonizing cancer-associated neurotransmitters by interpenetrating network hydrogels prevent postsurgical cancer relapse and metastases

Tumor-promoting niche after incomplete surgery resection(SR)can lead to more aggressive local progression and distant metastasis with augmented angiogenesis-immunosuppressive tumor microenvironment(TME).Herein,elevated neutrophil extracellular traps(NETs)and cancer-associated neurotransmitters(CANTs,e.g.,catecholamines)are firstly identified as two of the dominant inducements.Further,an injectable fibrin-alginate hydrogel with high tissue adhesion has been constructed to specifically co-deliver NETs inhibitor(DNase I)-encapsulated PLGA nanoparticles and an unselectiveβ-adrenergic receptor blocker(propranolol).The two components(i.e.,fibrin and alginate)can respond to two triggers(thrombin and Ca2+,respectively)in postoperative bleeding to gelate,shaping into an interpenetrating network(IPN)featuring high strength.The continuous release of DNase I and PR can wreck NETs and antagonize catecholamines to decrease microvessel density,blockade myeloid-derived suppressor cells,secrete various proinflammatory cytokines,potentiate natural killer cell function and hamper cytotoxic T cell exhaustion.The reprogrammed TME significantly suppress locally residual and distant tumors,induce strong immune memory effects and thus inhibit lung metastasis.Thus,targetedly degrading NETs and blocking CANTs enabled by this in-situ IPN-based hydrogel drug depot provides a simple and efficient approach against SR-induced cancer recurrence and metastasis.

Crossroads:Pathogenic role and therapeutic targets of neutrophil extracellular traps in rheumatoid arthritis

Rheumatoid arthritis(RA)is a prevalent autoimmune disease whose main features include chronic synovial inflammation,bone destruction,and joint degeneration.Neutrophils are often considered to be the first responders to inflammation and are a key presence in the inflammatory milieu of RA.Neutrophil extracellular traps(NETs),a meshwork of DNA-histone complexes and proteins released by activated neutrophils,are widely involved in the pathophysiology of autoimmune diseases,especially RA,in addition to playing a key role in the neutrophil innate immune response.NETs have been found to be an important source of citrullinated autoantigen antibodies and inflammatory factor release,which can activate RA synovial fibroblasts(FLS)and cause joint damage.This article reviews the role of NETs in the pathophysiology of RA,demonstrating the application of multiple molecules with various therapies,with a view to informing the discovery and development of novel biomarkers and therapeutic targets for RA.

Machine learning based on metabolomics unveils neutrophil extracellular trap-related metabolic signatures in non-small cell lung cancer patients undergoing chemoimmunotherapy

BACKGROUND Non-small cell lung cancer(NSCLC)is the primary form of lung cancer,and the combination of chemotherapy with immunotherapy offers promising treatment options for patients suffering from this disease.However,the emergence of drug resistance significantly limits the effectiveness of these therapeutic strategies.Consequently,it is imperative to devise methods for accurately detecting and evaluating the efficacy of these treatments.AIM To identify the metabolic signatures associated with neutrophil extracellular traps(NETs)and chemoimmunotherapy efficacy in NSCLC patients.METHODS In total,159 NSCLC patients undergoing first-line chemoimmunotherapy were enrolled.We first investigated the characteristics influencing clinical efficacy.Circulating levels of NETs and cytokines were measured by commercial kits.Liquid chromatography tandem mass spectrometry quantified plasma metabolites,and differential metabolites were identified.Least absolute shrinkage and selection operator,support vector machine-recursive feature elimination,and random forest algorithms were employed.By using plasma metabolic profiles and machine learning algorithms,predictive metabolic signatures were established.RESULTS First,the levels of circulating interleukin-8,neutrophil-to-lymphocyte ratio,and NETs were closely related to poor efficacy of first-line chemoimmunotherapy.Patients were classed into a low NET group or a high NET group.A total of 54 differential plasma metabolites were identified.These metabolites were primarily involved in arachidonic acid and purine metabolism.Three key metabolites were identified as crucial variables,including 8,9-epoxyeicosatrienoic acid,L-malate,and bis(monoacylglycerol)phosphate(18:1/16:0).Using metabolomic sequencing data and machine learning methods,key metabolic signatures were screened to predict NET level as well as chemoimmunotherapy efficacy.CONCLUSION The identified metabolic signatures may effectively distinguish NET levels and predict clinical benefit from chemoimmunotherapy in NSCLC patients.

Hypobaric Hypoxia Aggravates Renal Injury by Inducing the Formation of Neutrophil Extracellular Traps through the NF-κB Signaling Pathway

Objective The hypersensitivity of the kidney makes it susceptible to hypoxia injury.The involvement of neutrophil extracellular traps(NETs)in renal injury resulting from hypobaric hypoxia(HH)has not been reported.In this study,we aimed to investigate the expression of NETs in renal injury induced by HH and the possible underlying mechanism.Methods A total of 24 SD male rats were divided into three groups(n=8 each):normal control group,hypoxia group and hypoxia+pyrrolidine dithiocarbamate(PDTC)group.Rats in hypoxia group and hypoxia+PDTC group were placed in animal chambers with HH which was caused by simulating the altitude at 7000 meters(oxygen partial pressure about 6.9 kPa)for 7 days.PDTC was administered at a dose of 100 mg/kg intraperitoneally once daily for 7 days.Pathological changes of the rat renal tissues were observed under a light microscope;the levels of serum creatinine(SCr),blood urea nitrogen(BUN),cell-free DNA(cf-DNA)and reactive oxygen species(ROS)were measured;the expression levels of myeloperoxidase(MPO),citrullinated histone H3(cit-H3),B-cell lymphoma 2(Bcl-2),Bax,nuclear factor kappa B(NF-κB)p65 and phospho-NF-κB p65(p-NF-κB p65)in rat renal tissues were detected by qRT-qPCR and Western blotting;the localization of NF-κB p65 expression in rat renal tissues was observed by immunofluorescence staining and the expression changes of NETs in rat renal tissues were detected by multiplex fluorescence immunohistochemical staining.Results After hypoxia,the expression of NF-κB protein in renal tissues was significantly increased,the levels of SCr,BUN,cf-DNA and ROS in serum were significantly increased,the formation of NETs in renal tissues was significantly increased,and a large number of tubular dilatation and lymphocyte infiltration were observed in renal tissues.When PDTC was used to inhibit NF-κB activation,NETs formation in renal tissue was significantly decreased,the expression level of Bcl-2 in renal tissues was significantly increased,the expression level of Bax was significantly decreased,and renal injury was significantly alleviated.Conclusion HH induces the formation of NETs through the NF-κB signaling pathway,and it promotes apoptosis and aggravates renal injury by decreasing Bcl-2 and increasing Bax expression.

Blood neutrophil extracellular traps:a novel target for the assessment of mammary health in transition dairy cows

Background:Mammary health is important for transition dairy cows and has been well recognized to exert decisive effects on animal welfare.However,the factors influencing mammary health are still unclear.Differential somatic cell count(DSCC)could reflect the mastitis risk since it is the percentage of neutrophils plus lymphocytes in total somatic cells and could be reflective of mammary health of dairy cows.This work aimed to investigate the assessment and prognosis of the health of transition cows based on blood neutrophil extracellular traps(NETs).Results:Eighty-four transition Holstein dairy cows were selected.The serum was sampled in all the animals at week 1 pre-and postpartum,and milk was sampled at week 1 postpartum.Based on the DSCC in milk at week 1,cows with lower(7.4%±4.07%,n=15)and higher(83.3%±1.21%,n=15)DSCCs were selected.High DSCC cows had higher levels of red blood cell counts(P<0.05),hemoglobin(P=0.07),and hematocrit(P=0.05),higher concentrations of serum oxidative variables[reactive oxygen species(P<0.05),malondialdehyde(P<0.05),protein carbonyl(P<0.05),and 8-hydroxy-2-deoxyguanosine(P=0.07)],higher levels of serum and milk NETs(P<0.05)and blood-milk barrier indicators,including serumβ-casein(P=0.05)and milk immunoglobulin G2(P=0.09),than those of low DSCC cows.In addition,lower concentrations of serum nutrient metabolites(cholesterol and albumin)(P<0.05)and a lower level of serum deoxyribonuclease I(P=0.09)were observed in high DSCC cows than in low DSCC cows.Among the assessments performed using levels of the three prepartum serum parameters(NETs,deoxyribonuclease I andβ-casein),the area under the curve(0.973)of NETs was the highest.In addition,the sensitivity(1.00)and specificity(0.93)were observed for the discrimination of these cows using NETs levels with a critical value of 32.2 ng/mL(P<0.05).Conclusions:The formation of NETs in blood in transition dairy cows may damage the integrity of the blood-milk barrier and thereby increase the risk for mastitis in postpartum cows.

Inhibiting the formation of neutrophil extracellular trapping: a potential mechanism of Chinese medicine in the treatment of ischemic stroke

Ischemic stroke(IS)is the main killer that endangers the health and life of middle-aged and elderly people worldwide.Inflammatory response plays a key regulatory role in the pathogenesis of IS.After cerebral ischemia,leukocytes rapidly accumulate,penetrate blood vessels and infiltrate brain tissue,thereby activating pro-inflammatory factors in the infarct area to exacerbate nerve damage.Neutrophil extracellular traps(NETs)are fibrous mesh structures released by activated neutrophils outside the cell,which can clear pathogens and cell debris,induce inflammatory responses and exacerbate cerebral ischemia-reperfusion(CI/R)injury.Various traditional Chinese medicines and their main components can improve neurological function defects after IS,and inhibit the formation of NETs,which opens up a new direction for the study of traditional Chinese medicines in the prevention and treatment of IS.

Neutrophil extracellular traps mediate the crosstalk between glioma progression and the tumor microenvironment via the HMGB1/RAGE/IL-8 axis

Objective:Neutrophil extracellular traps(NETs)produced by tumor-infiltrating neutrophils(TINs)are associated with poor prognosis in patients with several types of cancer.However,the mechanisms underlying the involvement of NETs in glioma progression remain largely unknown.This study aimed to elucidate the roles of NETs in biological processes that drive the crosstalk between glioma progression and the tumor microenvironment.Methods:Neutrophil infiltration and NETs formation were investigated in glioma tissue through immunohistochemistry,and their relationships with clinicopathological features and outcomes were statistically evaluated.The effects of NETs on glioma cell progression were studied in a co-culture system.In vivo and in vitro experiments validated the reactive oxygen species activity and cytokine production of TINs,as well as the ERK signaling pathway activation and the metastasis of gliomas.Results:Neutrophil infiltration and NETs formation were induced in high-grade glioma compared with low-grade glioma.NETs induced by TINs were determined to be an oncogenic marker of high-grade gliomas and to be involved in cell proliferation and invasion.NETs overproduction promoted glioma cell proliferation,migration,and invasion.Furthermore,HMGB1 was found to bind to RAGE and activate the NF-κB signaling pathway in vitro.In addition,NETs stimulated the NF-κB signaling pathway,thus promoting IL-8 secretion in glioblastoma.Subsequently,IL-8 recruited neutrophils which in turn mediated NETs formation via the PI3 K/AKT/ROS axis in TINs.Conclusions:Our results suggest that NETs produced by TINs mediate the crosstalk between glioma progression and the tumor microenvironment by regulating the HMGB1/RAGE/IL-8 axis.Targeting NETs formation or IL-8 secretion may be an effective approach to inhibit glioma progression.

Neutrophil extracellular traps participate in the development of cancer-associated thrombosis in patients with gastric cancer

BACKGROUND The development of venous thromboembolism(VTE) is associated with high mortality among gastric cancer(GC) patients. Neutrophil extracellular traps(NETs) have been reported to correlate with the prothrombotic state in some diseases, but are rarely reported in GC patients.AIM To investigate the effect of NETs on the development of cancer-associated thrombosis in GC patients.METHODS The levels of NETs in blood and tissue samples of patients were analyzed by ELISA, flow cytometry, and immunofluorescence staining. NET generation and hypercoagulation of platelets and endothelial cells(ECs) in vitro were observed by immunofluorescence staining. NET procoagulant activity(PCA) was determined by fibrin formation and thrombin–antithrombin complex(TAT) assays.Thrombosis in vivo was measured in a murine model induced by flow stenosis in the inferior vena cava(IVC).RESULTS NETs were likely to form in blood and tissue samples of GC patients compared with healthy individuals. In vitro studies showed that GC cells and their conditioned medium, but not gastric mucosal epithelial cells, stimulated NET release from neutrophils. In addition, NETs induced a hypercoagulable state of platelets by upregulating the expression of phosphatidylserine and Pselectin on the cells. Furthermore, NETs stimulated the adhesion of normal platelets on glass surfaces. Similarly, NETs triggered the conversion of ECs to hypercoagulable phenotypes by downregulating the expression of their intercellular tight junctions but upregulating that of tissue factor. Treatment of normal platelets or ECs with NETs augmented the level of plasma fibrin formation and the TAT complex. In the models of IVC stenosis, tumor-bearing mice showed a stronger ability to form thrombi, and NETs abundantly accumulated in the thrombi of tumorbearing mice compared with control mice. Notably, the combination of deoxyribonuclease I,activated protein C, and sivelestat markedly abolished the PCA of NETs.CONCLUSION GC-induced NETs strongly increased the risk of VTE development both in vitro and in vivo. NETs are potential therapeutic targets in the prevention and treatment of VTE in GC patients.

Neutrophil extracellular traps in gastrointestinal cancer

Gastrointestinal(GI)cancer is a high-risk malignancy and is characterized by high mortality and morbidity worldwide.Neutrophil extracellular traps(NETs),a weblike structure consisting of chromatin DNA with interspersed cytoplasmic and granule proteins,are extruded by activated neutrophils to entrap and kill bacteria and fungi.However,accumulating evidence shows that NETs are related to the progression and metastasis of cancer.In clinical studies,NETs infiltrate primary GI cancer tissues and are even more abundant in metastatic lesions.The quantity of NETs in peripheral blood is revealed to be associated with ascending clinical tumour stages,indicating the role of NETs as a prognostic markers in GI cancer.Moreover,several inhibitors of NETs or NET-related proteins have been discovered and used to exert anti-tumour effects in vitro or in vivo,suggesting that NETs can be regarded as targets in the treatment of GI cancer.In this review,we will focus on the role of NETs in gastric cancer and colorectal cancer,generalizing their effects on tumour-related thrombosis,invasion and metastasis.Recent reports are also listed to show the latest evidences of how NETs affect GI cancer.Additionally,notwithstanding the scarcity of systematic studies elucidating the underlying mechanisms of the interaction between NETs and cancer cells,we highlight the potential importance of NETs as biomarkers and anti-tumour therapeutic targets.

Neutrophil extracellular traps in the intestinal mucosa of Eimeria-infected animals

Objective:To investigate the presence of neutrophil extracellular traps(NETs) in vivo by analysing intestinal sections from experimentally Eimeria bovis-and naturally Eimeria arloingi-infected animals.Methods:Intestinal samples of Eimeria arloingi-and Eimeria bovis-infected animals were analysed by using immunohistochemical and fluorescence approach by using monoclonal antibodies.Results:Classical NET components were confirmed by co-localization of extracellular DNA being decorated with neutrophil elastase and histones in Eimeria-infected tissue samples.Here,extrusion of NETs was exclusively detected in intestinal polymorphonuclear neutrophils infiltrating Eimeria-infected sites.In vivo NETs were either found in close proximity or in direct contact to different Eimeria stages suggesting a stage-independent process.NETs were also found within the gut lumen driven by polymorphonuclear neutrophils that were contacting released oocysts.Conclusions:We postulate that NETs might play an important role in innate defence reactions in coccidiosis therefore significantly altering the outcome of infection.

Do neutrophil extracellular traps contribute to the heightened risk of thrombosis in inflammatory diseases?

Thrombotic events,both arterial and venous,are a major health concern worldwide. Further,autoimmune diseases,such as systemic lupus erythematosus,anti-neutrophil cytoplasmic antibody(ANCA)-associated vasculitis,and antiphospholipid syndrome,predispose to thrombosis,and thereby push the risk for these morbid events even higher. In recent years,neutrophils have been identified as important players in both arterial and venous thrombosis. Specifically,chromatin-based structures called neutrophil extracellular traps(NETs) play a key role in activating the coagulation cascade,recruiting platelets,and serving as scaffolding upon which the thrombus can be assembled. At the same time,neutrophils and NETs are emerging as important mediators of pathogenic inflammation in the aforementioned autoimmune diseases. Here,we first review the general role of NETs in thrombosis. We then posit that exaggerated NET release contributes to the prothrombotic diatheses of systemic lupus erythematosus,ANCA-associated vasculitis,and antiphospholipid syndrome.

Icaritin inhibits the progression of urothelial cancer by suppressing PADI2-mediated neutrophil infiltration and neutrophil extracellular trap formation

Tumor relapse and metastasis are the major causes of mortality associated with urothelial cancer.In the tumor microenvironment,negative regulatory molecules and various immune cell subtypes suppress antitumor immunity.The inflammatory microenvironment,associated with neutrophils and neutrophil extracellular traps(NETs),promotes tumor metastasis.However,no drugs are currently available to specifically inhibit neutrophils and NETs.In this study,we first demonstrated that icaritin(ICT),a Chinese herbal remedy that is a first-line treatment for advanced and incurable hepatocellular carcinoma,reduces NETs caused by suicidal NETosis and prevents neutrophil infiltration in the tumor microenvironment.Mechanistically,ICT binds to and inhibits the expression of PADI2 in neutrophils,thereby suppressing PADI2-mediated histone citrullination.Moreover,ICT inhibits ROS generation,suppresses the MAPK signaling pathway,and inhibits NET-induced tumor metastasis.Simultaneously,ICT inhibits tumoral PADI2-mediated histone citrullination,which consequently suppresses the transcription of neutrophil-recruiting genes such as GM-CSF and IL-6.The downregulation of IL-6 expression,in turn,forms a regulatory feedback loop through the JAK2/STAT3/IL-6 axis.Through a retrospective study of clinical samples,we found a correlation between neutrophils,NETs,UCa prognosis,and immune evasion.Combining ICT with immune checkpoint inhibitors may have synergistic effects.In summary,our study demonstrated that ICT could be a novel inhibitor of NETs and a novel UCa treatment.

Association of the immediate perioperative dynamics of circulating DNA levels and neutrophil extracellular traps formation in cancer patients

Objectives:Elevated circulating DNA(cirDNA)concentrations were found to be associated with trauma or tissue damage which suggests involvement of inflammation or cell death in post-operative cirDNA release.We carried out the first prospective,multicenter study of the dynamics of cirDNA and neutrophil extracellular trap(NETs)markers during the perioperative period from 24 h before surgery up to 72 h after curative surgery in cancer patients.Methods:We examined the plasma levels of two NETs protein markers[myeloperoxidase(MPO)and neutrophil elastase(NE)],as well as levels of cirDNA of nuclear(cir-nDNA)and mitochondrial(cir-mtDNA)origin in 29 colon,prostate,and breast cancer patients and in 114 healthy individuals(HI).Results:The synergistic analytical information provided by these markers revealed that:(i)NETs formation contributes to post-surgery conditions;(i)post-surgery cir-nDNA levels were highly associated with NE and MPO in colon cancer[r=0.60(P<0.001)and r=0.53(P<0.01),respectivelyl,but not in prostate and breast cancer;(i)each tumor type shows a specific pattern of cir-nDNA and NETs marker dynamics,but overall the pre-and post-surgery median values of cir-nDNA,NE,and MPO were significantly higher in cancer patients than in HI.Conclusion:Taken as a whole,our work reveals the association of NETs formation with the elevated cir-nDNA release during a cancer patient's perioperative period,depending on surgical procedure or cancer type.By contrast,cir-mtDNA is poorly associated with NETs formation in the studied perioperative period,which would appear to indicate a different mechanism of release or suggest mitochondrial dysfunction.

A crucial role of neutrophil extracellular traps in pulmonary infectious diseases

Neutrophil extracellular traps(NETs),extrusions of intracellular DNA with attached granular material that exert an antibacterial effect through entangling,isolating,and immobilizing microorganisms,have been extensively studied in recent decades.The primary role of NETs is to entrap and facilitate the killing of bacteria,fungi,viruses,and parasites,preventing bacterial and fungal dissemination.NET formation has been described in many pulmonary diseases,including both infectious and non-infectious.NETs are considered a double-edged sword.As innate immune cells,neutrophils release NETs to kill pathogens and remove cellular debris.However,the dele-terious effects of excessive NET release in lung disease are particularly important because NETs and by-products of NETosis can directly induce epithelial and endothelial cell death while simultaneously inducing inflammatory cytokine secretion and immune-mediated thrombosis.Thus,NET formation must be tightly regulated to preserve the anti-microbial capability of NETs while minimizing damage to the host.In this review,we summarized the recent updates on the mechanism of NETs formation and pathophysiology associated with excessive NETs,aiming to provide insights for research and treatment of pulmonary infectious diseases.

Elevated neutrophil extracellular traps by HBV-mediated S100A9-TLR4/RAGE-ROS cascade facilitate the growth and metastasis of hepatocellular carcinoma

Background:Neutrophil extracellular traps(NETs)are considered significant contributors to cancer progression,especially metastasis.However,it is still unclear whether NETs are involved in hepatitis B virus(HBV)-related hepatocarcinogenesis and have potential clinical significance during evaluation and management for hepatocellular carcinoma(HCC).In this study,we aimed to investigate the functional mechanism of NETs in HBV-related hepatocarcinogenesis and their clinical significance.Methods:A total of 175 HCC patients with and without HBV infection and 58 healthy controls were enrolled in this study.NETs weremeasured in tissue specimens,freshly isolated neutrophils and blood serum from these patients,and the correlation of circulating serum NETs levels with malignancy was evaluated.The mechanism by which HBV modulates NETs formation was explored using cell-based studies.In addition,in vitro and in vivo experiments were further performed to clarify the functional mechanism of NETs on the growth and metastasis of HCC.Results:We observed an elevated level of NETs in blood serum and tissue specimens from HCC patients,especially those infected with HBV.NETs facilitated the growth and metastasis of HCC both in vitro and in vivo,which were mainly dominated by increased angiogenesis,epithelial-mesenchymal transition(EMT)-related cell migration,matrix metalloproteinases(MMPs)-induced extracellular matrix(ECM)degradation and NETs-mediated cell trapping.Inhibition of NETs generation by DNase 1 effectively abrogated the NETs-aroused HCC growth and metastasis.In addition,HBV-induced S100A9 accelerated the generation of NETs,which was mediated by activation of toll-like receptor(TLR4)/receptor for advanced glycation end products(RAGE)-reactive oxygen species(ROS)signaling.Further,circulatory NETs were found to correlate with viral load,TNM stage and metastasis status in HBV-related HCC,and the identified NETs could predict extrahepatic metastasis,with an area under the ROC curve(AUC)of 0.83 and 90.3%sensitivity and 62.8%specificity at a cutoff value of 0.32.Conclusions:Our findings indicated that activation of RAGE/TLR4-ROS signaling by HBV-induced S100A9 resulted in abundant NETs formation,which subsequently facilitated the growth and metastasis of HCC cells.More importantly,the identified circulatory NETs exhibited potential as an alternative biomarker for predicting extrahepatic metastasis in HBV-related HCC.

Novel neutrophil extracellular trap-related mechanisms in diabetic wounds inspire a promising treatment strategy with hypoxia-challenged small extracellular vesicles

Neutrophil extracellular traps(NETs)have been considered a significant unfavorable factor for wound healing in diabetes,but the mechanisms remain unclear.The therapeutic application of small extracellular vesicles(sEVs)derived from mesenchymal stem cells(MSCs)has received considerable attention for their properties.Hypoxic preconditioning is reported to enhance the therapeutic potential of MSC-derived sEVs in regenerative medicine.Therefore,the aim of this study is to illustrate the detailed mechanism of NETs in impairment of diabetic wound healing and develop a promising NET-targeting treatment based on hypoxic pretreated MSC-derived sEVs(Hypo-sEVs).Excessive NETs were found in diabetic wounds and in high glucose(HG)-induced neutrophils.Further research showed that high concentration of NETs impaired the function of fibroblasts through activating endoplasmic reticulum(ER)stress.Hypo-sEVs efficiently promoted diabetic wound healing and reduced the excessive NET formation by transferring miR-17-5p.Bioinformatic analysis and RNA interference experiment revealed that miR-17-5p in Hypo-sEVs obstructed the NET formation by targeting TLR4/ROS/MAPK pathway.Additionally,miR-17-5p overexpression decreased NET formation and overcame NET-induced impairment in fibroblasts,similar to the effects of Hypo-sEVs.Overall,we identify a previously unrecognized NET-related mechanism in diabetic wounds and provide a promising NET-targeting strategy for wound treatment.

Shifting focus from bacteria to host neutrophil extracellular traps of biodegradable pure Zn to combat implant centered infection

The widespread use of orthopedic implants to support or replace bones is increasingly threatened by the risk of incurable bacterial infections,impenetrable microbial biofilms,and irreversible antibiotic resistance.In the past,the development of anti-infective biomaterials focused solely on direct antibacterial properties while ignoring the host’s immune response.Inspired by the clearance of infection by the innate neutrophil response and partici-pation in anti-infectious immunity of Zn ions,we report an innovative neutrophil extracellular traps(NETs)strategy,induced by biodegradable pure Zn,which achieved therapeutic efficacy toward biomaterial-related infections.Our in vitro and in vivo data showed that pure Zn was favorable for NETs formation by promoting the release of DNA fibers and granule proteins in a reactive oxygen species(ROS)-dependent manner,thereby retraining and degrading bacteria with an efficiency of up to 99.5%.Transcriptome analysis revealed that cytoskeletal rearrangement and toll-like receptor(TLR)signaling pathway were also involved in Zn-induced NETs formation.Furthermore,the in vivo results of a Staphylococcus aureus(S.aureus)-infected rat model veri-fied that pure Zn potentiated the bactericidal capability of neutrophils around implants,and promoted osseointegration in S.aureus-infected rat femurs.This antibacterial immunity concept lays a foundation for the development of other antibacterial biomaterials and holds great promise for treating orthopedic infections.

Wip1 inhibits neutrophil extracellular traps to promote abscess formation in mice by directly dephosphorylating Coronin-1a

Neutrophil extracellular traps (NETs) participate in the rapid inhibition and clearance of pathogens during infection;however, the molecular regulation of NET formation remains poorly understood. In the current study, we found that inhibition of the wild-type p53-induced phosphatase 1 (Wip1) significantly suppressed the activity of Staphylococcus aureus (S. aureus) and accelerated abscess healing in S. aureus-induced abscess model mice by enhancing NET formation. A Wip1 inhibitor significantly enhanced NET formation in mouse and human neutrophils in vitro. High-resolution mass spectrometry and biochemical assays demonstrated that Coro1a is a substrate of Wip1. Further experiments also revealed that Wip1 preferentially and directly interacts with phosphorylated Coro1a than compared to unphosphorylated inactivated Coro1a. The phosphorylated Ser426 site of Coro1a and the 28–90 aa domain of Wip1 are essential for the direct interaction of Coro1a and Wip1 and for Wip1 dephosphorylation of p-Coro1a Ser426. Wip1 deletion or inhibition in neutrophils significantly upregulated the phosphorylation of Coro1a-Ser426, which activated phospholipase C and subsequently the calcium pathway, the latter of which promoted NET formation after infection or lipopolysaccharide stimulation. This study revealed Coro1a to be a novel substrate of Wip1 and showed that Wip1 is a negative regulator of NET formation during infection. These results support the potential application of Wip1 inhibitors to treat bacterial infections.

Neutrophil Extracellular Traps in Autoimmune Diseases

INTRODUCTIONIn 2004, NETosis was first reported as an important step to kill bacteria by neutrophils. During the process ofN ETosis, neutrophil extracellular traps （NETs） that contain large web-like structures of decondensed chromatin decorated with histones and intracellular components, including neutrophil elastase （NE）, myeloperoxidase （MPO）, high mobility group protein B I （HMGBI）, and proteinase 3 （PR3）, are extruded into the extracellular space, The structures of NETs enable the neutrophil to potently catch and kill pathogens at the site of inflammation. Furthermore, increasing studies have identified the presence of NETs in autoimmune diseases. NETs deliver multiple autoantigens to host immtme system that induce autoimmune responses and directly release damage-associated molecular patterns to amplify inflammatory responses. Therefore, NETs are commonly described to play a crucial role in the pathogenesis and development of autoimmune diseases in recent years.