Neutrophil extracellular traps in immunity and disease.Nat Rev Immunol. 2018;18:134-147. [PMID: 28990587 DOI: 10.1038/nri.2017.105]

Membranous nephropathy: pathogenesis and treatments

Membranous nephropathy (MN), an autoimmune disease, can manifest at any age and is among the most common causes of nephrotic syndrome in adults. In 80% of cases, the specific etiology of MN remains unknown, while the remaining cases are linked to drug use or underlying conditions like systemic lupus erythematosus, hepatitis B virus, or malignancy. Although about one-third of patients may achieve spontaneous complete or partial remission with conservative management, another third face an elevated risk of disease progression, potentially leading to end-stage renal disease within 10 years. The identification of phospholipase A2 receptor as the primary target antigen in MN has brought about a significant shift in disease management and monitoring. This review explores recent advancements in the pathophysiology of MN, encompassing pathogenesis, clinical presentations, diagnostic criteria, treatment options, and prognosis, with a focus on emerging developments in pathogenesis and therapeutic strategies aimed at halting disease progression. By synthesizing the latest research findings and clinical insights, this review seeks to contribute to the ongoing efforts to enhance our understanding and management of this challenging autoimmune disorder.

TREM1 facilitates the development of gastric cancer through regulating neutrophil extracellular traps-mediated macrophage polarization

Triggering receptor expressed on myeloid cell 1 (TREM1) elevation is associated with the unfavorable prognosis of gastric cancer (GC) patients. This work uncovered the effects and mechanism of TREM1 in GC. IHC staining examined TREM1 expression in GC tissues. TREM1-knockout and TREM1 knock-in mice were generated prior to the construction of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced GC mice model. H&E staining detected the pathological alternations of gastric tissues. IHC staining tested Ki67 expression. Wright-Giemsa staining performed neutrophil counting and flow cytometry analysis measured neutrophil infiltration. ELISA analyzed serum and tissue myeloperoxidase (MPO) levels and serum MPO-DNA levels. Immunofluorescence, Western blotting and related kits detected NETs formation. Immunofluorescence and IHC staining evaluated macrophage polarization. In MNNG-treated GES-1 cells and phorbal myristate acetate (PMA)-treated neutrophils, TREM1 expression was also examined. CCK-8 method and Western blotting assayed cell proliferation. Western blotting and immunofluorescence detected NETs formation. Flow cytometry analysis detected the changes of macrophage typing. TREM1 was overexpressed in tumor tissues, MNNG-treated GES-1 cells and PMA-treated neutrophils. TREM1 deficiency hindered tumor growth, reduced neutrophil infiltration, NETs formation and stimulated M1 macrophage polarization in MNNG-induced GC models. Neutrophil extracellular traps (NETs) degrader DNase-1 countervailed the impacts of TREM1 on MNNG-induced GC models in vivo. Collectively, TREM1 knockdown obstructed NETs-mediated M2 macrophage polarization to hamper GC progression.

Gastric cancer immunosuppressive microenvironment heterogeneity: implications for therapy development

Although immunotherapy has revolutionized solid tumor treatment, durable responses in gastric cancer (GC) remain limited. The heterogeneous tumor microenvironment (TME) facilitates immune evasion, contributing to resistance to conventional and immune therapies. Recent studies have highlighted how specific TME components in GC acquire immune escape capabilities through cancer-specific factors. Understanding the underlying molecular mechanisms and targeting the immunosuppressive TME will enhance immunotherapy efficacy and patient outcomes. This review summarizes recent advances in GC TME research and explores the role of the immune-suppressive system as a context-specific determinant. We also provide insights into potential treatments beyond checkpoint inhibition.

Triple threat: neutrophil ER stress, NETosis, airway inflammation escalation

This report aims to propose the novel term 'neutrophil endoplasmic reticulum (ER) stress' (NERS). NERS explores the influence of neutrophil extracellular trap (NET) formation and exacerbation of respiratory ailments. This inquiry aims to advance comprehension in neutrophil biology and respiratory health.

Sequential immunotherapy: towards cures for autoimmunity

Despite major progress in the treatment of autoimmune diseases in the past two decades, most therapies do not cure disease and can be associated with increased risk of infection through broad suppression of the immune system. However, advances in understanding the causes of autoimmune disease and clinical data from novel therapeutic modalities such as chimeric antigen receptor T cell therapies provide evidence that it may be possible to re-establish immune homeostasis and, potentially, prolong remission or even cure autoimmune diseases. Here, we propose a 'sequential immunotherapy' framework for immune system modulation to help achieve this ambitious goal. This framework encompasses three steps: controlling inflammation; resetting the immune system through elimination of pathogenic immune memory cells; and promoting and maintaining immune homeostasis via immune regulatory agents and tissue repair. We discuss existing drugs and those in development for each of the three steps. We also highlight the importance of causal human biology in identifying and prioritizing novel immunotherapeutic strategies as well as informing their application in specific patient subsets, enabling precision medicine approaches that have the potential to transform clinical care.

Extracellular traps in skin lesions infected with lymphocystis disease virus in black rockfish (Sebastes schlegelii)

The lymphocystis disease (LCD), caused by Lymphocystis disease virus (LCDV), is a benign and self-limiting disease described in a many freshwater and marine fish species. Hypertrophic fibroblasts and extensive aggregation of inflammatory cells are characteristics of LCD. In the present study, small animal imaging and ultrastructural investigations were carried out on the lymphocystis nodules of black rockfish (Sebastes schlegelii) naturally infected with lymphocystis iridovirus, to assess pathology, and the exudate with particular attention to the formation of extracellular traps (ETs) in vivo. Ex vivo were examined by nodules sections and primary cells stimulation. By histopathological analysis, the nodules contained infiltrated inflammatory cells and extensive basophilic fibrillar filaments at the periphery of the hypertrophied fibroblasts. ETs were assessed in nodules samples using indirect immunofluorescence to detect DNA and myeloperoxidase. Moreover, LCDV was able to infect peritoneal cells of black rockfish in vitro and induce the formation of ETs within 4 h. In summary, this study proved that ETs are involved in the response to LCDV infection and may be involved in formation of lymphoid nodules. Taken together, the findings provide a new perspective to determine the impact factors on the growth of nodules.

Neutrophil extracellular traps modulate chemotherapy efficacy and its adverse side effects

Neutrophils, major regulator of innate immunity have recently emerged as key components of the tumor microenvironment. The role of neutrophils in cancer has been linked to their ability to form neutrophil extracellular traps (NETs), structures composed of decondensed DNA decorated with enzymes that are released into the extracellular space. Here, we discuss the pivotal roles of NETs, in influencing responses to chemotherapy and its severe adverse effect. Highlighting recent insights, we discuss the dual nature of NETs in the context of chemotherapy treatment, examining their potential to either counteract or enhance treatment outcomes. Strategic targeting of NETs emerges as a promising avenue for determining combination therapies that could help counteracting resistance or enhancing chemotherapy efficacy as well as limiting complications due to this type of treatment.

PTP1B phosphatase dampens iPSC-derived neutrophil motility and antimicrobial function

Neutrophils are rapidly recruited to sites of infection and are critical for pathogen clearance. Therapeutic use of primary neutrophils has been limited, as they have a short lifespan and are not amenable to genetic manipulation. Human induced pluripotent stem cells (iPSCs) can provide a robust source of neutrophils for infusion and are genetically tractable. However, current work has indicated that dampened intracellular signaling limits iPSC-derived neutrophil (iNeutrophil) cellular activation and antimicrobial response. Here, we show that protein tyrosine phosphatase 1B (PTP1B) inhibits intracellular signaling and dampens iNeutrophil effector function. Deletion of the PTP1B phosphatase increased PI3K and ERK signaling and was associated with increased F-actin polymerization, cell migration, and phagocytosis. In contrast, other effector functions like NETosis and reactive oxygen species production were reduced. PTP1B-deficient neutrophils were more responsive to Aspergillus fumigatus and displayed rapid recruitment and control of hyphal growth. Accordingly, depletion of PTP1B increased production of inflammatory factors including the neutrophil chemokine interleukin-8. Taken together, these findings suggest that PTP1B limits iNeutrophil motility and antimicrobial function.

Myeloperoxidase as a Promising Therapeutic Target after Myocardial Infarction

Coronary artery disease (CAD) and myocardial infarction (MI) remain leading causes of death and disability worldwide. CAD begins with the formation of atherosclerotic plaques within the intimal layer of the coronary arteries, a process driven by persistent arterial inflammation and oxidation. Myeloperoxidase (MPO), a mammalian haem peroxidase enzyme primarily expressed within neutrophils and monocytes, has been increasingly recognised as a key pro-inflammatory and oxidative enzyme promoting the development of vulnerable coronary atherosclerotic plaques that are prone to rupture, and can precipitate a MI. Mounting evidence also implicates a pathogenic role for MPO in the inflammatory process that follows a MI, which is characterised by the rapid infiltration of activated neutrophils into the damaged myocardium and the release of MPO. Excessive and persistent cardiac inflammation impairs normal cardiac healing post-MI, resulting in adverse cardiac outcomes and poorer long-term cardiac function, and eventually heart failure. This review summarises the evidence for MPO as a significant oxidative enzyme contributing to the inappropriate inflammatory responses driving the progression of CAD and poor cardiac healing after a MI. It also details the proposed mechanisms underlying MPO's pathogenic actions and explores MPO as a novel therapeutic target for the treatment of unstable CAD and cardiac damage post-MI.

The mammosphere-derived epithelial cell secretome modulates neutrophil functions in the bovine model

Background

Innovative therapies against bacterial infections are needed. One approach is to focus on host-directed immunotherapy (HDT), with treatments that exploit natural processes of the host immune system. The goals of this type of therapy are to stimulate protective immunity while minimizing inflammation-induced tissue damage. We use non-traditional large animal models to explore the potential of the mammosphere-derived epithelial cell (MDEC) secretome, consisting of all bioactive factors released by the cells, to modulate host immune functions. MDEC cultures are enriched for mammary stem and progenitor cells and can be generated from virtually any mammal. We previously demonstrated that the bovine MDEC secretome, collected and delivered as conditioned medium (CM), inhibits the growth of bacteria in vitro and stimulates functions related to tissue repair in cultured endothelial and epithelial cells.

Methods

The immunomodulatory effects of the bovine MDEC secretome on bovine neutrophils, an innate immune cell type critical for resolving bacterial infections, were determined in vitro using functional assays. The effects of MDEC CM on neutrophil molecular pathways were explored by evaluating the production of specific cytokines by neutrophils and examining global gene expression patterns in MDEC CM-treated neutrophils. Enzyme linked immunosorbent assays were used to determine the concentrations of select proteins in MDEC CM and siRNAs were used to reduce the expression of specific MDEC-secreted proteins, allowing for the identification of bioactive factors modulating neutrophil functions.

Results

Neutrophils exposed to MDEC secretome exhibited increased chemotaxis and phagocytosis and decreased intracellular reactive oxygen species and extracellular trap formation, when compared to neutrophils exposed to control medium. C-X-C motif chemokine 6, superoxide dismutase, peroxiredoxin-2, and catalase, each present in the bovine MDEC secretome, were found to modulate neutrophil functions.

Conclusion

The MDEC secretome administered to treat bacterial infections may increase neutrophil recruitment to the site of infection, stimulate pathogen phagocytosis by neutrophils, and reduce neutrophil-produced ROS accumulation. As a result, pathogen clearance might be improved and local inflammation and tissue damage reduced.

Tumor cell-released autophagosomes (TRAPs) induce PD-L1-decorated NETs that suppress T-cell function to promote breast cancer pulmonary metastasis

BACKGROUND

Lung metastasis is the primary cause of breast cancer-related mortality. Neutrophil extracellular traps (NETs) are involved in the progression of breast cancer. However, the mechanism of NET formation is not fully understood. This study posits that tumor cell-released autophagosomes (TRAPs) play a crucial role in this process.

METHODS

TRAPs were isolated from breast cancer cell lines to analyze their impact on NET formation in both human and mouse neutrophils. The study used both in vitro and in vivo models, including Toll-like receptor 4 (TLR4-/-) mice and engineered breast cancer cell lines. Immunofluorescence, ELISA, Western blotting, RNA sequencing, and flow cytometry were employed to dissect the signaling pathways leading to NET production and to explore their immunosuppressive effects, particularly focusing on the impact of NETs on T-cell function. The therapeutic potential of targeting TRAP-induced NETs and their immunosuppressive functions was evaluated using DNase I and αPD-L1 antibodies. Clinical relevance was assessed by correlating circulating levels of TRAPs and NETs with lung metastasis in patients with breast cancer.

RESULTS

This study showed that TRAPs induced the formation of NETs in both human and mouse neutrophils by using the high mobility group box 1 and activating the TLR4-Myd88-ERK/p38 signaling axis. More importantly, PD-L1 carried by TRAP-induced NETs inhibited T-cell function in vitro and in vivo, thereby contributing to the formation of lung premetastatic niche (PMN) immunosuppression. In contrast, Becn1 KD-4T1 breast tumors with decreased circulating TRAPs in vivo reduced the formation of NETs, which in turn attenuated the immunosuppressive effects in PMN and resulted in a reduction of breast cancer pulmonary metastasis in murine models. Moreover, treatment with αPD-L1 in combination with DNase I that degraded NETs restored T-cell function and significantly reduced tumor metastasis. TRAP levels in the peripheral blood positively correlated with NET levels and lung metastasis in patients with breast cancer.

CONCLUSIONS

Our results demonstrate a novel role of TRAPs in the formation of PD-L1-decorated NETs, which may provide a new strategy for early detection and treatment of pulmonary metastasis in patients with breast cancer.

Salidroside ameliorates acute liver transplantation rejection in rats by inhibiting neutrophil extracellular trap formation

Acute rejection is an important factor affecting the survival of recipients after liver transplantation. Salidroside has various properties, including anti-inflammatory, antioxidant, and hepatoprotective properties. This study aims to investigate whether salidroside can prevent acute rejection after liver transplantation and to examine the underlying mechanisms involved. An in vivo acute rejection model is established in rats that are pretreated with tacrolimus (1 mg/kg/d) or salidroside (10 or 20 mg/kg/d) for seven days after liver transplantation. In addition, an in vitro experiment is performed using neutrophils incubated with salidroside (1, 10, 50 or 100 μM). Hematoxylin-eosin staining, terminal deoxynucleotidyl transferase dUTP nick-end labeling staining, immunosorbent assays, immunofluorescence analysis, Evans blue staining, and western blot analysis are performed to examine the impact of salidroside on NET formation and acute rejection in vitro and in vivo. We find that Salidroside treatment reduces pathological liver damage, serum aminotransferase level, and serum levels of IL-1β, IL-6, and TNF-α in vivo. The expressions of proteins associated with the HMGB1/TLR-4/MAPK signaling pathway (HMGB1, TLR-4, p-ERK1/2, p-JNK, p-P38, cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, IL-1β, TNF-α, and IL-6) are also decreased after salidroside treatment. In vitro experiments show that the release of HMGB1/TLR-4/MAPK signaling pathway-associated proteins from neutrophils treated with lipopolysaccharide is decreased by salidroside. Moreover, salidroside inhibits NETosis and protects against acute rejection by regulating the HMGB1/TLR-4/MAPK signaling pathway. Furthermore, salidroside combined with tacrolimus has a better effect than either of the other treatments alone. In summary, salidroside can prevent acute liver rejection after liver transplantation by reducing neutrophil extracellular trap development through the HMGB1/TLR-4/MAPK signaling pathway.

Coordinated inflammation and immune response transcriptional regulation in breast cancer molecular subtypes

Breast cancer, characterized by its complexity and diversity, presents significant challenges in understanding its underlying biology. In this study, we employed gene co-expression network analysis to investigate the gene composition and functional patterns in breast cancer subtypes and normal breast tissue. Our objective was to elucidate the detailed immunological features distinguishing these tumors at the transcriptional level and to explore their implications for diagnosis and treatment. The analysis identified nine distinct gene module clusters, each representing unique transcriptional signatures within breast cancer subtypes and normal tissue. Interestingly, while some clusters exhibited high similarity in gene composition between normal tissue and certain subtypes, others showed lower similarity and shared traits. These clusters provided insights into the immune responses within breast cancer subtypes, revealing diverse immunological functions, including innate and adaptive immune responses. Our findings contribute to a deeper understanding of the molecular mechanisms underlying breast cancer subtypes and highlight their unique characteristics. The immunological signatures identified in this study hold potential implications for diagnostic and therapeutic strategies. Additionally, the network-based approach introduced herein presents a valuable framework for understanding the complexities of other diseases and elucidating their underlying biology.

Neutrophil extracellular traps induce pyroptosis of pulmonary microvascular endothelial cells by activating the NLRP3 inflammasome

Excessive formation of neutrophil extracellular traps (NETs) may lead to myositis-related interstitial lung disease (ILD). There is evidence that NETs can directly injure vascular endothelial cells and play a pathogenic role in the inflammatory exudation of ILD. However, the specific mechanism is unclear. This study aimed to investigate the specific mechanism underlying NET-induced injury to human pulmonary microvascular endothelial cells (HPMECs). HPMECs were stimulated with NETs (200 ng/ml) in vitro. Cell death was detected by propidium iodide staining. The morphological changes of the cells were observed by transmission electron microscopy (TEM). Pyroptosis markers were detected by western blot, immunofluorescence, and quantitative real-time polymerase chain reaction, and the related inflammatory factor Interleukin-1β (IL-1β) was verified by enzyme-linked immunosorbent assay (ELISA). Compared with the control group, HPMECs mortality increased after NET stimulation, and the number of pyroptosis vacuoles in HPMECs was further observed by TEM. The pulmonary microvascular endothelial cells (PMECs) of the experimental autoimmune myositis mouse model also showed a trend of pyroptosis in vivo. Cell experiment further confirmed the significantly high expression of the NLRP3 inflammasome and pyroptosis-related markers, including GSDMD and inflammatory factor IL-1β. Pretreated with the NLRP3 inhibitor MCC950, the activation of NLRP3 inflammasome and pyroptosis of HPMECs were effectively inhibited. Our study confirmed that NETs promote pulmonary microvascular endothelial pyroptosis by activating the NLRP3 inflammasome, suggesting that NETs-induced pyroptosis of PMECs may be a potential pathogenic mechanism of inflammatory exudation in ILD.

A Two-Pronged Delivery Strategy Disrupting Positive Feedback Loop of Neutrophil Extracellular Traps for Metastasis Suppression

Neutrophil extracellular traps (NETs) severely affect tumor metastasis through a self-perpetuating feedback loop involving two key steps: (1) mitochondrial aerobic respiration-induced hypoxia promotes NET formation and (2) NETs enhance mitochondrial metabolism to exacerbate hypoxia. Herein, we propose a two-pronged approach with the activity of NET-degrading and mitochondrion-damaging by simultaneously targeting drugs to NETs and tumor mitochondria of this loop. In addition to specifically recognizing and eliminating extant NETs, the NET-targeting nanoparticle also reduces NET-induced mitochondrial biogenesis, thus inhibiting the initial step of the feedback loop and mitigating extant NETs' impact on tumor metastasis. Simultaneously, the mitochondrion-targeting system intercepts mitochondrial metabolism and alleviates tumor hypoxia, inhibiting neutrophil infiltration and subsequent NET formation, which reduces the source of NETs and disrupts another step of the self-amplifying feedback loop. Together, the combination significantly reduces the formation of NET-tumor cell clusters by disrupting the interaction between NETs and tumor mitochondria, thereby impeding the metastatic cascade including tumor invasion, hematogenous spread, and distant colonization. This work represents an innovative attempt to disrupt the feedback loop in tumor metastasis, offering a promising therapeutic approach restraining NET-assisted metastasis.

Neuroinflammation in Alzheimer's disease: insights from peripheral immune cells

Alzheimer's disease (AD) is a serious brain disorder characterized by the presence of beta-amyloid plaques, tau pathology, inflammation, neurodegeneration, and cerebrovascular dysfunction. The presence of chronic neuroinflammation, breaches in the blood-brain barrier (BBB), and increased levels of inflammatory mediators are central to the pathogenesis of AD. These factors promote the penetration of immune cells into the brain, potentially exacerbating clinical symptoms and neuronal death in AD patients. While microglia, the resident immune cells of the central nervous system (CNS), play a crucial role in AD, recent evidence suggests the infiltration of cerebral vessels and parenchyma by peripheral immune cells, including neutrophils, T lymphocytes, B lymphocytes, NK cells, and monocytes in AD. These cells participate in the regulation of immunity and inflammation, which is expected to play a huge role in future immunotherapy. Given the crucial role of peripheral immune cells in AD, this article seeks to offer a comprehensive overview of their contributions to neuroinflammation in the disease. Understanding the role of these cells in the neuroinflammatory response is vital for developing new diagnostic markers and therapeutic targets to enhance the diagnosis and treatment of AD patients.

Classical monocyte ontogeny dictates their functions and fates as tissue macrophages

Classical monocytes (CMs) are ephemeral myeloid immune cells that circulate in the blood. Emerging evidence suggests that CMs can have distinct ontogeny and originate from either granulocyte-monocyte- or monocyte-dendritic-cell progenitors (GMPs or MDPs). Here, we report surface markers that allowed segregation of murine GMP- and MDP-derived CMs, i.e., GMP-Mo and MDP-Mo, as well as their functional characterization, including fate definition following adoptive cell transfer. GMP-Mo and MDP-Mo yielded an equal increase in homeostatic CM progeny, such as blood-resident non-classical monocytes and gut macrophages; however, these cells differentially seeded various other selected tissues, including the dura mater and lung. Specifically, GMP-Mo and MDP-Mo differentiated into distinct interstitial lung macrophages, linking CM dichotomy to previously reported pulmonary macrophage heterogeneity. Collectively, we provide evidence for the existence of two functionally distinct CM subsets in the mouse that differentially contribute to peripheral tissue macrophage populations in homeostasis and following challenge.

Active myeloperoxidase: a promising biomarker to differentiate "acute" and "low-grade" peri-prosthetic joint infections from aseptic failures

Introduction

The accurate distinction between periprosthetic joint infections (PJI) and aseptic failures (AF) is of paramount importance due to differences in treatment. However, this could be challenging by using the current criteria. Various synovial fluid biomarkers are being assessed to improve the diagnostic accuracy. Myeloperoxidase (MPO), an enzyme contained in the granules of neutrophils, may be a promising biomarker for PJI.

Methods

Synovial fluids of 99 patients (n = 65 PJI according to EBJIS criteria; n = 34 AF) were collected in two specialized orthopedic centers. PJI were divided into acute (n = 33) and low-grade (n = 32) according to previously published classification. An activity assay specific for active MPO was performed in each sample. Ability of MPO to correctly discriminate patients with PJI from AF was determined by ROC analysis. The best discriminating cut-off value was determined by calculating the J Youden index. For all analyses, a P value < 0.05 was considered statistically significant.

Results

Active MPO was higher in PJI than AF (P < 0.0001). The ROC analysis revealed a significant area under the curve (AUC: 0.86; 95% CI: 0.78-0.93, P < 0.0001). A cut-off value of 561.9 U/mL, with good sensitivity (0.69) and specificity (0.88), discriminated between AF and PJI (accuracy 75.76%, 95% CI: 66.11-83.81%, positive likelihood ratio 5.88, 95% CI: 2.31-14.98 and negative likelihood ratio 0.35, 95%CI: 0.24-0.51). No difference in MPO levels was found between acute and chronic low-grade PJI.

Conclusion

The proposed assay appears to be a reliable and affordable tool for detecting the active MPO in synovial fluid, with promising characteristics of sensitivity and specificity in discriminating both acute and low-grade PJI from AF. Further studies are needed to confirm MPO diagnostic cut-off values and validate their use in the routine clinical practice.

Neutrophil Extracellular Traps: A Crucial Factor in Post-Surgical Abdominal Adhesion Formation

Post-surgical abdominal adhesions, although poorly understood, are highly prevalent. The molecular processes underlying their formation remain elusive. This review aims to assess the relationship between neutrophil extracellular traps (NETs) and the generation of postoperative peritoneal adhesions and to discuss methods for mitigating peritoneal adhesions. A keyword or medical subject heading (MeSH) search for all original articles and reviews was performed in PubMed and Google Scholar. It included studies assessing peritoneal adhesion reformation after abdominal surgery from 2003 to 2023. After assessing for eligibility, the selected articles were evaluated using the Critical Appraisal Skills Programme checklist for qualitative research. The search yielded 127 full-text articles for assessment of eligibility, of which 7 studies met our criteria and were subjected to a detailed quality review using the Critical Appraisal Skills Programme (CASP) checklist. The selected studies offer a comprehensive analysis of adhesion pathogenesis with a special focus on the role of neutrophil extracellular traps (NETs) in the development of peritoneal adhesions. Current interventional strategies are examined, including the use of mechanical barriers, advances in regenerative medicine, and targeted molecular therapies. In particular, this review emphasizes the potential of NET-targeted interventions as promising strategies to mitigate postoperative adhesion development. Evidence suggests that in addition to their role in innate defense against infections and autoimmune diseases, NETs also play a crucial role in the formation of peritoneal adhesions after surgery. Therefore, therapeutic strategies that target NETs are emerging as significant considerations for researchers. Continued research is vital to fully elucidate the relationship between NETs and post-surgical adhesion formation to develop effective treatments.

Inflammation in the Peripheral Nervous System after Injury

Nerve injury is a common condition that occurs as a result of trauma, iatrogenic injury, or long-lasting stimulation. Unlike the central nervous system (CNS), the peripheral nervous system (PNS) has a strong capacity for self-repair and regeneration. Peripheral nerve injury results in the degeneration of distal axons and myelin sheaths. Macrophages and Schwann cells (SCs) can phagocytose damaged cells. Wallerian degeneration (WD) makes the whole axon structure degenerate, creating a favorable regenerative environment for new axons. After nerve injury, macrophages, neutrophils and other cells are mobilized and recruited to the injury site to phagocytose necrotic cells and myelin debris. Pro-inflammatory and anti-inflammatory factors involved in the inflammatory response provide a favorable microenvironment for peripheral nerve regeneration and regulate the effects of inflammation on the body through relevant signaling pathways. Previously, inflammation was thought to be detrimental to the body, but further research has shown that appropriate inflammation promotes nerve regeneration, axon regeneration, and myelin formation. On the contrary, excessive inflammation can cause nerve tissue damage and pathological changes, and even lead to neurological diseases. Therefore, after nerve injury, various cells in the body interact with cytokines and chemokines to promote peripheral nerve repair and regeneration by inhibiting the negative effects of inflammation and harnessing the positive effects of inflammation in specific ways and at specific times. Understanding the interaction between neuroinflammation and nerve regeneration provides several therapeutic ideas to improve the inflammatory microenvironment and promote nerve regeneration.

Current and future immunotherapeutic approaches in pancreatic cancer treatment

Pancreatic cancer is a major cause of cancer-related death, but despondently, the outlook and prognosis for this resistant type of tumor have remained grim for a long time. Currently, it is extremely challenging to prevent or detect it early enough for effective treatment because patients rarely exhibit symptoms and there are no reliable indicators for detection. Most patients have advanced or spreading cancer that is difficult to treat, and treatments like chemotherapy and radiotherapy can only slightly prolong their life by a few months. Immunotherapy has revolutionized the treatment of pancreatic cancer, yet its effectiveness is limited by the tumor's immunosuppressive and hard-to-reach microenvironment. First, this article explains the immunosuppressive microenvironment of pancreatic cancer and highlights a wide range of immunotherapy options, including therapies involving oncolytic viruses, modified T cells (T-cell receptor [TCR]-engineered and chimeric antigen receptor [CAR] T-cell therapy), CAR natural killer cell therapy, cytokine-induced killer cells, immune checkpoint inhibitors, immunomodulators, cancer vaccines, and strategies targeting myeloid cells in the context of contemporary knowledge and future trends. Lastly, it discusses the main challenges ahead of pancreatic cancer immunotherapy.

Neutrophil Extracellular Traps (NETs) Are Associated with Type 2 Diabetes and Diabetic Foot Ulcer Related Amputation: A Prospective Cohort Study

INTRODUCTION

The prevalence of diabetes mellitus and its sequelae has been on the rise, and diabetic foot ulcer (DFU) is the leading cause of non-traumatic lower limb amputation globally. The rising occurrence and financial burden associated with DFU necessitate improved clinical assessment and treatment. Diabetes has been found to enhance the formation of neutrophil extracellular traps (NETs) by neutrophils, and excessive NETs have been implicated in tissue damage and impaired wound healing. However, there is as yet insufficient evidence to clarify the value of NETs in assessing and predicting outcomes of DFU.

METHODS

We designed this prospective study with three cohorts formed from type 2 diabetes mellitus (T2DM) patients with DFU (n = 200), newly diagnosed T2DM patients (n = 42), and healthy donors (n = 38). Serum levels of NETs were detected for all groups, and the prognostic value for DFU-related amputation was analyzed.

RESULTS

The results showed that serum NET levels of the DFU group were significantly higher than in the T2DM group (P < 0.05), which also had significantly elevated serum NET levels compared to healthy donors (P < 0.05). Multivariate Cox regression showed that serum NET levels, diabetic foot surgical history, and Wagner grade were the risk factors for amputation (P < 0.05), and these three variables also exhibited the highest coefficient values in additional Lasso Cox regression. For patients with DFU, Kaplan-Meier curves showed that high serum NET levels associated with higher amputation probability (HR = 0.19, P < 0.01) and ROC curve based on NET value showed good validity for amputation (AUC: 0.727, CI 0.651-0.803).

CONCLUSION

Elevated serum NET levels serve as an easily accessible serological prognostic marker for assessing the risk of DFU-related amputation, thereby offering evaluation metrics for healthcare providers. Further investigations are necessary to understand the mechanisms driving this relationship.

Neutrophil Targeting Platform Reduces Neutrophil Extracellular Traps for Improved Traumatic Brain Injury and Stroke Theranostics

Traumatic brain injuries (TBI) and stroke are major causes of morbidity and mortality in both developing and developed countries. The complex and heterogeneous pathophysiology of TBI and cerebral ischemia-reperfusion injury (CIRI), in addition to the blood-brain barrier (BBB) resistance, is a major barrier to the advancement of diagnostics and therapeutics. Clinical data showed that the severity of TBI and stroke is positively correlated with the number of neutrophils in peripheral blood and brain injury sites. Furthermore, neutrophil extracellular traps (NETs) released by neutrophils correlate with worse TBI and stroke outcomes by impairing revascularization and vascular remodeling. Therefore, targeting neutrophils to deliver NETs inhibitors to brain injury sites and reduce the formation of NETs can be an optimal strategy for TBI and stroke therapy. Herein, the study designs and synthesizes a reactive oxygen species (ROS)-responsive neutrophil-targeting delivery system loaded with peptidyl arginine deiminase 4 (PAD4) inhibitor, GSK484, to prevent the formation of NETs in brain injury sites, which significantly inhibited neuroinflammation and improved neurological deficits, and improved the survival rate of TBI and CIRI. This strategy may provide a groundwork for the development of targeted theranostics of TBI and stroke.

Monosodium Urate Crystal-Induced Pyroptotic Cell Death in Neutrophil and Macrophage Facilitates the Pathological Progress of Gout

Monosodium urate (MSU) crystal deposition in joints can lead to the infiltration of neutrophils and macrophages, and their activation plays a critical role in the pathological progress of gout. However, the role of MSU crystal physicochemical properties in inducing cell death in neutrophil and macrophage is still unclear. In this study, MSU crystals of different sizes are synthesized to explore the role of pyroptosis in gout. It is demonstrated that MSU crystals induce size-dependent pyroptotic cell death in bone marrow-derived neutrophils (BMNs) and bone marrow-derived macrophages (BMDMs) by triggering NLRP3 inflammasome-dependent caspase-1 activation and subsequent formation of N-GSDMD. Furthermore, it is demonstrated that the size of MSU crystal also determines the formation of neutrophil extracellular traps (NETs) and aggregated neutrophil extracellular traps (aggNETs), which are promoted by the addition of interleukin-1β (IL-1β). Based on these mechanistic understandings, it is shown that N-GSDMD oligomerization inhibitor, dimethyl fumarate (DMF), inhibits MSU crystal-induced pyroptosis in BMNs and J774A.1 cells, and it further alleviates the acute inflammatory response in MSU crystals-induced gout mice model. This study elucidates that MSU crystal-induced pyroptosis in neutrophil and macrophage is critical for the pathological progress of gout, and provides a new therapeutic approach for the treatment of gout.

Gliotoxin elicits immunotoxicity in the early innate immune system of ducks

Gliotoxin (GT) belongs to the epipolythiodioxopiperazine (ETP) family, which is considered a crucial virulence determinant among the secondary metabolites produced by Aspergillus fumigatus. The metabolites are commonly found in food and feed, contributing to the invasion and immune escape of Aspergillus fumigatus, thereby posing a significant threat to the health of livestock, poultry, and humans. Heterophil extracellular traps (HETs), a novel form of innate immune defense, have been documented in the chicken's innate immune systems for capturing and eliminating invading microbes. However, the effects and mechanisms of GT on the production of duck HETs in vitro remain unknown. In this study, we first confirmed the presence of HETs in duck innate immune systems and further investigated the molecular mechanism underlying GT-induced HETs release. Our results demonstrate that GT can trigger typical release of HETs in duck. The structures of GT-induced HETs structures were characterized by DNA decoration, citrullinated histones 3, and elastase. Furthermore, NADPH oxidase, glycolysis, ERK1/2 and p38 signaling pathway were found to regulate GT-induced HETs. In summary, our findings reveal that gliotoxin activates HETs release in the early innate immune system of duck while providing new insights into the immunotoxicity of GT towards ducks.

Proteomic profiling of mesenchymal stem cell-derived extracellular vesicles: Impact of isolation methods on protein cargo

Extracellular vesicles (EVs) are nanosized vesicles with a lipid bilayer that are secreted by cells and play a critical role in cell-to-cell communication. Despite the promising reports regarding their diagnostic and therapeutic potential, the utilization of EVs in the clinical setting is limited due to insufficient information about their cargo and a lack of standardization in isolation and analysis methods. Considering protein cargos in EVs as key contributors to their therapeutic potency, we conducted a tandem mass tag (TMT) quantitative proteomics analysis of three subpopulations of mesenchymal stem cell (MSC)-derived EVs obtained through three different isolation techniques: ultracentrifugation (UC), high-speed centrifugation (HS), and ultracentrifugation on sucrose cushion (SU). Subsequently, we checked EV marker expression, size distribution, and morphological characterization, followed by bioinformatic analysis. The bioinformatic analysis of the proteome results revealed that these subpopulations exhibit distinct molecular and functional characteristics. The choice of isolation method impacts the proteome of isolated EVs by isolating different subpopulations of EVs. Specifically, EVs isolated through the high-speed centrifugation (HS) method exhibited a higher abundance of ribosomal and mitochondrial proteins. Functional apoptosis assays comparing isolated mitochondria with EVs isolated through different methods revealed that HS-EVs, but not other EVs, induced early apoptosis in cancer cells. On the other hand, EVs isolated using the sucrose cushion (SU) and ultracentrifugation (UC) methods demonstrated a higher abundance of proteins primarily involved in the immune response, cell-cell interactions and extracellular matrix interactions. Our analyses unveil notable disparities in proteins and associated biological functions among EV subpopulations, underscoring the importance of meticulously selecting isolation methods and resultant EV subpopulations based on the intended application.

Role of microglia after subarachnoid hemorrhage

Subarachnoid hemorrhage is a devastating sequela of aneurysm rupture. Because it disproportionately affects younger patients, the population impact of hemorrhagic stroke from subarachnoid hemorrhage is substantial. Secondary brain injury is a significant contributor to morbidity after subarachnoid hemorrhage. Initial hemorrhage causes intracranial pressure elevations, disrupted cerebral perfusion pressure, global ischemia, and systemic dysfunction. These initial events are followed by two characterized timespans of secondary brain injury: the early brain injury period and the delayed cerebral ischemia period. The identification of varying microglial phenotypes across phases of secondary brain injury paired with the functions of microglia during each phase provides a basis for microglia serving a critical role in both promoting and attenuating subarachnoid hemorrhage-induced morbidity. The duality of microglial effects on outcomes following SAH is highlighted by the pleiotropic features of these cells. Here, we provide an overview of the key role of microglia in subarachnoid hemorrhage-induced secondary brain injury as both cytotoxic and restorative effectors. We first describe the ontogeny of microglial populations that respond to subarachnoid hemorrhage. We then correlate the phenotypic development of secondary brain injury after subarachnoid hemorrhage to microglial functions, synthesizing experimental data in this area.

Transcription factor Nrf2 activation regulates NETosis, endothelial injury, and kidney disease in myeloperoxidase-positive antineutrophil cytoplasmic antibody-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease pathologically characterized by vascular necrosis with inflammation. During AAV development, activated neutrophils produce reactive oxygen species (ROS), leading to the aberrant formation of neutrophil extracellular traps (NETs) via NETosis and subsequent fibrinoid vascular necrosis. Nuclear factor-erythroid 2-related factor 2 (Nrf2) functions as an intracellular defense system to counteract oxidative stress by providing antioxidant properties. Herein, we explored the role of Nrf2 in the pathogenesis of AAV. The role and mechanism of Nrf2 in ANCA-stimulated neutrophils and subsequent endothelial injury were evaluated in vitro using Nrf2 genetic deletion and Nrf2 activator treatment. In corresponding in vivo studies, the role of Nrf2 in ANCA-transfer AAV and spontaneous AAV murine models was examined. Pharmacological activation of Nrf2 in vitro suppressed ANCA-induced NET formation via the inhibition of ROS. In contrast, NET formation was enhanced in Nrf2-deficient neutrophils. Furthermore, Nrf2 activation protected endothelial cells from ANC-induced NETs-mediated injury. In vivo, Nrf2 activation ameliorated glomerulonephritis in two AAV models by upregulating antioxidants and inhibiting ROS-mediated NETs. Furthermore, Nrf2 activation restrained the expansion of splenic immune cells, including T lymphocytes and limited the infiltration of Th17 cells into the kidney. In contrast, Nrf2 genetic deficiency exacerbated vasculitis in a spontaneous AAV model. Thus, the pathophysiological process in AAV may be downregulated by Nrf2 activation, potentially leading to a new therapeutic strategy by regulating NETosis.

Immunological role of Gas6/TAM signaling in hemostasis and thrombosis

The immune system is an emerging regulator of hemostasis and thrombosis. The concept of immunothrombosis redefines the relationship between coagulation and immunomodulation, and the Gas6/Tyro3-Axl-MerTK (TAM) signaling pathway builds the bridge across them. During coagulation, Gas6/TAM signaling pathway not only activates platelets, but also promotes thrombosis through endothelial cells and vascular smooth muscle cells involved in inflammatory responses. Thrombosis appears to be a common result of a Gas6/TAM signaling pathway-mediated immune dysregulation. TAM TK and its ligands have been found to be involved in coagulation through the PI3K/AKT or JAK/STAT pathway in various systemic diseases, providing new perspectives in the understanding of immunothrombosis. Gas6/TAM signaling pathway serves as a breakthrough target for novel therapeutic strategies to improve disease management. Many preclinical and clinical studies of TAM receptor inhibitors are in process, confirming the pivotal role of Gas6/TAM signaling pathway in immunothrombosis. Therapeutics targeting the TAM receptor show potential both in anticoagulation management and immunotherapy. Here, we review the immunological functions of the Gas6/TAM signaling pathway in coagulation and its multiple mechanisms in diseases identified to date, and discuss the new clinical strategies that may generated by these roles.

Neutrophil extracellular traps induced by IL-1β promote endothelial dysfunction and aggravate limb ischemia

Vascular inflammation and endothelial dysfunction contribute to vascular diseases. While neutrophil extracellular traps (NETs) participate in some vascular pathologies, their roles in lower limb ischemia remain poorly defined. This study investigated the functional significance of NETs in vascular inflammation and remodeling associated with limb ischemia. Single-cell RNA sequencing (scRNA-seq) and flow cytometry revealed neutrophil activation and upregulated NETs formation in human limb ischemia, with immunofluorescence confirming IL-1β-induced release of NETs for vascular inflammation. Endothelial cell activation was examined via scRNA-seq and western blotting, indicating enhanced proliferation, expression of adhesion molecules (VCAM-1, ICAM-1), inflammatory cytokines (IL-1β, IL-6) and decreased expression of VE-cadherin, that could be mediated by NETs to exacerbate endothelial inflammation. Mechanistically, NETs altered endothelial cell function via increased pSTAT1/STAT1 signaling. Vascular inflammation and subsequent ischemia were alleviated in vivo by NETosis or IL-1β inhibition in ischemic mice. IL-1β-NETs induce endothelial activation and inflammation in limb ischemia by stimulating STAT1 signaling. Targeting NETs may thus represent a novel therapeutic strategy for inflammatory vascular diseases associated with limb ischemia. Graphical abstract of NETs regulation of the development of vascular inflammation in lower limb ischemia via pSTAT1/STAT1 signaling pathway.

Multi-model analysis of gallbladder cancer reveals the role of OxLDL-absorbing neutrophils in promoting liver invasion

BACKGROUND

Gallbladder cancer (GBC) is the most common and lethal malignancy of the biliary tract that lacks effective therapy. In many GBC cases, infiltration into adjacent organs or distant metastasis happened long before the diagnosis, especially the direct liver invasion, which is the most common and unfavorable way of spreading.

METHODS

Single-cell RNA sequencing (scRNA-seq), spatial transcriptomics (ST), proteomics, and multiplexed immunohistochemistry (mIHC) were performed on GBC across multiple tumor stages to characterize the tumor microenvironment (TME), focusing specifically on the preferential enrichment of neutrophils in GBC liver invasion (GBC-LI).

RESULTS

Multi-model Analysis reveals the immunosuppressive TME of GBC-LI that was characterized by the enrichment of neutrophils at the invasive front. We identified the context-dependent transcriptional states of neutrophils, with the Tumor-Modifying state being associated with oxidized low-density lipoprotein (oxLDL) metabolism. In vitro assays showed that the direct cell-cell contact between GBC cells and neutrophils led to the drastic increase in oxLDL uptake of neutrophils, which was primarily mediated by the elevated OLR1 on neutrophils. The oxLDL-absorbing neutrophils displayed a higher potential to promote tumor invasion while demonstrating lower cancer cytotoxicity. Finally, we identified a neutrophil-promoting niche at the invasive front of GBC-LI that constituted of KRT17+ GBC cells, neutrophils, and surrounding fibroblasts, which may help cultivate the oxLDL-absorbing neutrophils.

CONCLUSIONS

Our study reveals the existence of a subset of pro-tumoral neutrophils with a unique ability to absorb oxLDL via OLR1, a phenomenon induced through cell-cell contact with KRT17+ GBC cells in GBC-LI.

Characterization of a predictive signature for tumor microenvironment and immunotherapy response in hepatocellular carcinoma involving neutrophil extracellular traps

Neutrophil extracellular traps (NETs) and other factors play a significant role in impacting the prognosis of patients with Hepatocellular carcinoma (HCC). Nevertheless, further research is warranted to fully elucidate the prognostic implications of NETs in patients with HCC. We employed a hierarchical clustering technique to examine the Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) data and identified subtypes associated with NETs. Subsequently, we utilized LASSO regression analysis to identify a distinct gene expression pattern within these subtypes. The strength of this signature was further validated through analysis of TCGA-LIHC and International Cancer Genome Consortium-Liver Cancer (ICGC-LIRI-JP) data. Our findings resulted in the construction of a six-gene signature related to NETs, which can predict survival outcomes in HCC patients. To enhance the predictive accuracy of our tool, we developed a nomogram that integrates the NETs signature with clinicopathological characteristics. We validated the significance of NETs in HCC patients using qRT-PCR and immunohistochemistry assays, along with in vitro experiments targeting high-risk genes. Furthermore, our exploration of the immune microenvironment uncovered augmented immune-specific metrics within the low-risk cohort, implying potential disparities in immune-related attributes between the high-risk and low-risk contingents. In summary, the NETs signature we discovered serves as a valuable biomarker and provides guidance for personalized therapy in HCC patients.

Relationship between thrombus vWF and NETs with clinical severity and peripheral blood immunocytes' indicators in patients with acute ischemic stroke

OBJECTIVE

To investigate the association between von Willebrand factor (vWF) and neutrophil extracellular traps (NETs) in thrombus with clinical severity and peripheral blood immunocytes' indicators in patients with early-stage acute ischemic stroke (AIS).

METHODS

A retrospective study was conducted using the clinical data of 66 patients with AIS who underwent endovascular mechanical thrombectomy and had their thrombus samples collected. The concentrations of vWF and NETs in the thrombus samples were quantitatively assessed. Peripheral blood samples taken in the early stages of the disease were analyzed for total white blood cell counts (WBC), ratios of neutrophils (NEU%), lymphocytes (LYM%), eosinophils (EOS%), and monocytes (MONO%). The severity of clinical symptoms in these patients was evaluated using the modified Rankin Scale (mRS), Essen Stroke Risk Score (ESRS), Barthel Index (BI), and National Institute of Health Stroke Scale (NIHSS).

RESULTS

Higher vWF levels in thrombus were associated with lower NIHSS scores, while higher NETs levels were associated with higher initial NIHSS scores. In the early stages of AIS, WBC count and vWF levels were negatively correlated, as well as NEU%. LYM% was positively correlated with vWF level; however, it was negatively correlated with NETs. EOS% was positively correlated with vWF levels.

CONCLUSION

In the early stages of AIS, a higher peripheral WBC count and NEU%, combined with decreased EOS% and LYM%, were significantly correlated with a lower vWF level in the thrombus, potentially indicating more severe symptoms. Consequently, the timely administration of vWF-targeted medications is recommended for such patients. Reduced LYM% is indicative of elevated NETs levels and correlated with more severe clinical symptoms. Therefore, the prompt initiation of NETs-targeted medication is warranted for these patients.

Neutrophil extracellular traps as a unique target in the treatment of inflammatory pain

Pain is a widespread motivation for seeking healthcare and stands as a substantial global public health concern. Despite comprehensive investigations into the mechanisms of pain sensitization induced by inflammation, efficacious treatments options remain scarce. Neutrophil extracellular traps (NETs) have been associated with the progression and tissue damage of diverse inflammatory diseases. This study aims to explore the impact of NETs on the progression of inflammatory pain and explore potential therapeutic approaches. Initially, we observed neutrophil infiltration and the formation of NETs in the left hind paw of mice with inflammatory pain induced by complete Freund's adjuvant (CFA). Furthermore, we employed the peptidyl arginine deiminase 4 (PAD4) inhibitor Cl-amidine (diluted at 50 mg/kg in saline, administered via tail vein injection once daily for three days) to impede NETs formation and administered DNase1 (diluted at 10 mg/kg in saline, once daily for three days) to break down NETs. We investigated the pathological importance of peripheral NETs formation in inflammatory pain and its influence on the activation of spinal dorsal horn microglia. The findings indicate that neutrophils infiltrating locally generate NETs, leading to an increased release of inflammatory mediators that worsen peripheral inflammatory reactions. Consequently, this results in the transmission of more harmful peripheral stimuli to the spinal cord, triggering microglial activation and NF-κB phosphorylation, thereby escalating neuroinflammation and fostering pain sensitization. Suppression of peripheral NETs can mitigate peripheral inflammation in mice with inflammatory pain, reverse mechanical and thermal hypersensitivity by suppressing microglial activation in the spinal cord, ultimately diminishing inflammatory pain. In conclusion, these discoveries propose that obstructing or intervening with NETs introduces a novel therapeutic avenue for addressing inflammatory pain.

Unraveling the Molecular Landscape of Neutrophil Extracellular Traps in Severe Asthma: Identification of Biomarkers and Molecular Clusters

Neutrophil extracellular traps (NETs) play a central role in chronic airway diseases. However, the precise genetic basis linking NETs to the development of severe asthma remains elusive. This study aims to unravel the molecular characterization of NET-related genes (NRGs) in severe asthma and to reliably identify relevant molecular clusters and biomarkers. We analyzed RNA-seq data from the Gene Expression Omnibus database. Interaction analysis revealed fifty differentially expressed NRGs (DE-NRGs). Subsequently, the non-negative matrix factorization algorithm categorized samples from severe asthma patients. A machine learning algorithm then identified core NRGs that were highly associated with severe asthma. DE-NRGs were correlated and subjected to protein-protein interaction analysis. Unsupervised consensus clustering of the core gene expression profiles delineated two distinct clusters (C1 and C2) characterizing severe asthma. Functional enrichment highlighted immune-related pathways in the C2 cluster. Core gene selection included the Boruta algorithm, support vector machine, and least absolute contraction and selection operator algorithms. Diagnostic performance was assessed by receiver operating characteristic curves. This study addresses the molecular characterization of NRGs in adult severe asthma, revealing distinct clusters based on DE-NRGs. Potential biomarkers (TIMP1 and NFIL3) were identified that may be important for early diagnosis and treatment of severe asthma.

Prognostic impact and immunotherapeutic implications of NETosis-related prognostic model in clear cell renal cell carcinoma

BACKGROUND

The ramifications of necroptosis on the prognostication of clear cell renal cell carcinoma (ccRCC) remain inadequately expounded.

METHODS

A prognostic model delineating the facets of necroptosis in ccRCC was constructed, employing a compendium of algorithms. External validation was effectuated using the E-MTAB-1980 dataset. The exploration of immune infiltration scores was undertaken through the exploitation of multiple algorithms. Single-cell RNA sequencing data were procured from the GSE171306 dataset. Real-time quantitative PCR (RT-qPCR) was engaged to scrutinize the differential expression of SLC25A37 across cancer and paracancer tissues, as well as diverse cell lines. Assessments of proliferative and metastatic alterations in 769-P and 786-O cells were accomplished through Cell Counting Kit-8 (CCK8) and wound healing assays.

RESULTS

The necroptosis-related signature (NRS) emerges as a discerning metric, delineating patients' immune attributes, tumor mutation burden, immunotherapy response, and drug susceptibility. Single-cell RNA sequencing analysis unveils the marked enrichment of SLC25A37 in tumor cells. Concurrently, RT-qPCR discloses the overexpression of SLC25A37 in both ccRCC tissues and cell lines. SLC25A37 knockdown mitigates the proliferative and metastatic propensities of 769-P and 786-O cells, as evidenced by CCK8 and wound healing assays.

CONCLUSION

The NRS assumes a pivotal role in ascertaining the prognosis, tumor mutation burden, immunotherapy response, drug susceptibility, and immune cell infiltration features of ccRCC patients. SLC25A37 emerges as a putative player in immunosuppressive microenvironments, thereby providing a prospective avenue for the design of innovative immunotherapeutic targets for ccRCC.

Novel Isolating Approaches to Circulating Tumor Cell Enrichment Based on Microfluidics: A Review

Circulating tumor cells (CTCs), derived from the primary tumor and carrying genetic information, contribute significantly to the process of tumor metastasis. The analysis and detection of CTCs can be used to assess the prognosis and treatment response in patients with tumors, as well as to help study the metastatic mechanisms of tumors and the development of new drugs. Since CTCs are very rare in the blood, it is a challenging problem to enrich CTCs efficiently. In this paper, we provide a comprehensive overview of microfluidics-based enrichment devices for CTCs in recent years. We explore in detail the methods of enrichment based on the physical or biological properties of CTCs; among them, physical properties cover factors such as size, density, and dielectric properties, while biological properties are mainly related to tumor-specific markers on the surface of CTCs. In addition, we provide an in-depth description of the methods for enrichment of single CTCs and illustrate the importance of single CTCs for performing tumor analyses. Future research will focus on aspects such as improving the separation efficiency, reducing costs, and increasing the detection sensitivity and accuracy.

Screening and Identification of Neutrophil Extracellular Trap-related Diagnostic Biomarkers for Pediatric Sepsis by Machine Learning

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.

Establishment of a neutrophil extracellular trap-related prognostic signature for colorectal cancer liver metastasis and expression validation of CYP4F3

Liver metastasis stands as the primary contributor to mortality among patients diagnosed with colorectal cancer (CRC). Neutrophil extracellular traps (NETs) emerge as pivotal players in the progression and metastasis of cancer, showcasing promise as prognostic biomarkers. Our objective is to formulate a predictive model grounded in genes associated with neutrophil extracellular traps and identify novel therapeutic targets for combating CRLM. We sourced gene expression profiles from the Gene Expression Omnibus (GEO) database. Neutrophil extracellular trap-related gene set was obtained from relevant literature and cross-referenced with the GEO datasets. Differentially expressed genes (DEGs) were identified through screening via the least absolute shrinkage and selection operator regression and random forest modeling, leading to the establishment of a nomogram and subtype analysis. Subsequently, a thorough analysis of the characteristic gene CYP4F3 was undertaken, and our findings were corroborated through immunohistochemical staining. We identified seven DEGs (ATG7, CTSG, CYP4F3, F3, IL1B, PDE4B, and TNF) and established nomograms for the occurrence and prognosis of CRLM. CYP4F3 is highly expressed in CRC and colorectal liver metastasis (CRLM), exhibiting a negative correlation with CRLM prognosis. It may serve as a potential therapeutic target for CRLM. A novel prognostic signature related to NETs has been developed, with CYP4F3 identified as a risk factor and potential target for CRLM.

Communications between Neutrophil-Endothelial Interaction in Immune Defense against Bacterial Infection

The endothelial barrier plays a critical role in immune defense against bacterial infection. Efficient interactions between neutrophils and endothelial cells facilitate the activation of both cell types. However, neutrophil activation can have dual effects, promoting bacterial clearance on one hand while triggering inflammation on the other. In this review, we provide a detailed overview of the cellular defense progression when neutrophils encounter bacteria, focusing specifically on neutrophil-endothelial interactions and endothelial activation or dysfunction. By elucidating the underlying mechanisms of inflammatory pathways, potential therapeutic targets for inflammation caused by endothelial dysfunction may be identified. Overall, our comprehensive understanding of neutrophil-endothelial interactions in modulating innate immunity provides deeper insights into therapeutic strategies for infectious diseases and further promotes the development of antibacterial and anti-inflammatory drugs.

CAP2 contributes to Parkinson's disease diagnosed by neutrophil extracellular trap-related immune activity

Introduction

Neutrophil extracellular traps (NETs) constitute a crucial element of the immune system, and dysfunction in immune responses is implicated in the susceptibility and progression of Parkinson's disease (PD). Nevertheless, the mechanism connecting PD and NETs remains unclear. This study aims to uncover potential NETs-related immune biomarkers and elucidate their role in PD pathogenesis.

Methods

Through differential gene analysis of PD and NETs in GSE7621 datasets, we identified two PD subtypes and explored potential biological pathways. Subsequently, using ClusterWGCNA, we pinpointed pertinent genes and developed clinical diagnostic models. We then optimized the chosen model and evaluated its association with immune infiltration. Validation was conducted using the GSE20163 dataset. Screening the single-cell dataset GSE132758 revealed cell populations associated with the identified gene.

Results

Our findings identified XGB as the optimal diagnostic model, with CAP2 identified as a pivotal gene. The risk model effectively predicted overall diagnosis rates, demonstrating a robust correlation between infiltrating immune cells and genes related to the XGB model.

Discussion

In conclusions, we identified PD subtypes and diagnostic genes associated with NETs, highlighting CAP2 as a pivotal gene. These findings have significant implications for understanding potential molecular mechanisms and treatments for PD.

Multiomics integration reveals NETosis heterogeneity and TLR2 as a prognostic biomarker in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant neoplasm characterized by a poor prognosis and limited therapeutic strategy. The PDAC tumor microenvironment presents a complex heterogeneity, where neutrophils emerge as the predominant constituents of the innate immune cell population. Leveraging the power of single-cell RNA-seq, spatial RNA-seq, and multi-omics approaches, we included both published datasets and our in-house patient cohorts, elucidating the inherent heterogeneity in the formation of neutrophil extracellular traps (NETs) and revealed the correlation between NETs and immune suppression. Meanwhile, we constructed a multi-omics prognostic model that suggested the patients exhibiting downregulated expression of NETs may have an unfavorable outcome. We also confirmed TLR2 as a potent prognosis factor and patients with low TLR2 expression had more effective T cells and an overall survival extension for 6 months. Targeting TLR2 might be a promising strategy to reverse immunosuppression and control tumor progression for an improved prognosis.

Precise modulation and use of reactive oxygen species for immunotherapy

Reactive oxygen species (ROS) play an important role in regulating the immune system by affecting pathogens, cancer cells, and immune cells. Recent advances in biomaterials have leveraged this mechanism to precisely modulate ROS levels in target tissues for improving the effectiveness of immunotherapies in infectious diseases, cancer, and autoimmune diseases. Moreover, ROS-responsive biomaterials can trigger the release of immunotherapeutics and provide tunable release kinetics, which can further boost their efficacy. This review will discuss the latest biomaterial-based approaches for both precise modulation of ROS levels and using ROS as a stimulus to control the release kinetics of immunotherapeutics. Finally, we will discuss the existing challenges and potential solutions for clinical translation of ROS-modulating and ROS-responsive approaches for immunotherapy, and provide an outlook for future research.

Association of vascular netosis with COVID-19 severity in asymptomatic and symptomatic patients

We examined from a large exploratory study cohort of COVID-19 patients (N = 549) a validated panel of neutrophil extracellular traps (NETs) markers in different categories of disease severity. Neutrophil elastase (NE), myeloperoxidase (MPO), and circulating nuclear DNA (cir-nDNA) levels in plasma were seen to gradually and significantly (p < 0.0001) increase with the disease severity: mild (3.7, 48.9, and 15.8 ng/mL, respectively); moderate (9.8, 77.5, and 27.7 ng/mL, respectively); severe (11.7, 99.5, and 29.0 ng/mL, respectively); and critical (13.1, 110.2, and 46.0 ng/mL, respectively); and are also statistically different with healthy individuals (N = 140; p < 0.0001). All observations made in relation to the Delta variant-infected patients are in line with Omicron-infected patients. We unexpectedly observed significantly higher levels of NETs in asymptomatic individuals as compared to healthy subjects (p < 0.0001). Moreover, the balance of cir-nDNA and circulating mitochondrial DNA level was affected in COVID-19 infected patients attesting to mitochondrial dysfunction.

Cellular communication network factor 1 promotes retinal leakage in diabetic retinopathy via inducing neutrophil stasis and neutrophil extracellular traps extrusion

BACKGROUND

Diabetic retinopathy (DR) is a major cause of blindness and is characterized by dysfunction of the retinal microvasculature. Neutrophil stasis, resulting in retinal inflammation and the occlusion of retinal microvessels, is a key mechanism driving DR. These plugging neutrophils subsequently release neutrophil extracellular traps (NETs), which further disrupts the retinal vasculature. Nevertheless, the primary catalyst for NETs extrusion in the retinal microenvironment under diabetic conditions remains unidentified. In recent studies, cellular communication network factor 1 (CCN1) has emerged as a central molecule modulating inflammation in pathological settings. Additionally, our previous research has shed light on the pathogenic role of CCN1 in maintaining endothelial integrity. However, the precise role of CCN1 in microvascular occlusion and its potential interaction with neutrophils in diabetic retinopathy have not yet been investigated.

METHODS

We first examined the circulating level of CCN1 and NETs in our study cohort and analyzed related clinical parameters. To further evaluate the effects of CCN1 in vivo, we used recombinant CCN1 protein and CCN1 overexpression for gain-of-function, and CCN1 knockdown for loss-of-function by intravitreal injection in diabetic mice. The underlying mechanisms were further validated on human and mouse primary neutrophils and dHL60 cells.

RESULTS

We detected increases in CCN1 and neutrophil elastase in the plasma of DR patients and the retinas of diabetic mice. CCN1 gain-of-function in the retina resulted in neutrophil stasis, NETs extrusion, capillary degeneration, and retinal leakage. Pre-treatment with DNase I to reduce NETs effectively eliminated CCN1-induced retinal leakage. Notably, both CCN1 knockdown and DNase I treatment rescued the retinal leakage in the context of diabetes. In vitro, CCN1 promoted adherence, migration, and NETs extrusion of neutrophils.

CONCLUSION

In this study, we uncover that CCN1 contributed to retinal inflammation, vessel occlusion and leakage by recruiting neutrophils and triggering NETs extrusion under diabetic conditions. Notably, manipulating CCN1 was able to hold therapeutic promise for the treatment of diabetic retinopathy.

DNA of Neutrophil Extracellular Traps Binds TMCO6 to Impair CD8+ T-cell Immunity in Hepatocellular Carcinoma

Neutrophil extracellular traps (NET), formed by the extracellular release of decondensed chromatin and granules, have been shown to promote tumor progression and metastasis. Tumor-associated neutrophils in hepatocellular carcinoma (HCC) are prone to NET formation, highlighting the need for a more comprehensive understanding of the mechanisms of action of NETs in liver cancer. Here, we showed that DNA of NETs (NET-DNA) binds transmembrane and coiled-coil domains 6 (TMCO6) on CD8+ T cells to impair antitumor immunity and thereby promote HCC progression. TGFβ1 induced NET formation, which recruited CD8+ T cells. Binding to NET-DNA inhibited CD8+ T cells function while increasing apoptosis and TGFβ1 secretion, forming a positive feedback loop to further stimulate NET formation and immunosuppression. Mechanistically, the N-terminus of TMCO6 interacted with NET-DNA and suppressed T-cell receptor signaling and NFκB p65 nuclear translocation. Blocking NET formation by inhibiting PAD4 induced potent antitumor effects in wild-type mice but not TMCO6-/- mice. In clinical samples, CD8+ T cells expressing TMCO6 had an exhausted phenotype. TGFβ1 signaling inhibition or TMCO6 deficiency combined with anti-PD-1 abolished NET-driven HCC progression in vivo. Collectively, this study unveils the role of NET-DNA in impairing CD8+ T-cell immunity by binding TMCO6 and identifies targeting this axis as an immunotherapeutic strategy for blocking HCC progression.

SIGNIFICANCE

TMCO6 is a receptor for DNA of NETs that mediates CD8+ T-cell dysfunction in HCC, indicating that the NET-TMCO6 axis is a promising target for overcoming immunosuppression in liver cancer.

Restraint Stress-Induced Neutrophil Inflammation Contributes to Concurrent Gastrointestinal Injury in Mice

Psychological stress increases risk of gastrointestinal tract diseases. However, the mechanism behind stress-induced gastrointestinal injury is not well understood. The objective of our study is to elucidate the putative mechanism of stress-induced gastrointestinal injury and develop an intervention strategy. To achieve this, we employed the restraint stress mouse model, a well-established method to study the pathophysiological changes associated with psychological stress in mice. By orally administering gut-nonabsorbable Evans blue dye and monitoring its plasma levels, we were able to track the progression of gastrointestinal injury in live mice. Additionally, flow cytometry was utilized to assess the viability, death, and inflammatory status of splenic leukocytes, providing insights into the stress-induced impact on the innate immune system associated with stress-induced gastrointestinal injury. Our findings reveal that neutrophils represent the primary innate immune leukocyte lineage responsible for stress-induced inflammation. Splenic neutrophils exhibited elevated expression levels of the pro-inflammatory cytokine IL-1, cellular reactive oxygen species, mitochondrial burden, and cell death following stress challenge compared to other innate immune cells such as macrophages, monocytes, and dendritic cells. Regulated cell death analysis indicated that NETosis is the predominant stress-induced cell death response among other analyzed regulated cell death pathways. NETosis culminates in the formation and release of neutrophil extracellular traps, which play a crucial role in modulating inflammation by binding to pathogens. Treatment with the NETosis inhibitor GSK484 rescued stress-induced neutrophil extracellular trap release and gastrointestinal injury, highlighting the involvement of neutrophil extracellular traps in stress-induced gastrointestinal inflammation. Our results suggest that neutrophil NETosis could serve as a promising drug target for managing psychological stress-induced gastrointestinal injuries.

NET-Related Gene as Potential Diagnostic Biomarkers for Diabetic Tubulointerstitial Injury

Background: Tubulointerstitial injury plays a pivotal role in the progression of diabetic kidney disease (DKD), yet the link between neutrophil extracellular traps (NETs) and diabetic tubulointerstitial injury is still unclear. Methods: We analyzed microarray data (GSE30122) from the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) associated with DKD's tubulointerstitial injury. Functional and pathway enrichment analyses were conducted to elucidate the involved biological processes (BP) and pathways. Weighted gene coexpression network analysis (WGCNA) identified modules associated with DKD. LASSO regression and random forest selected NET-related characteristic genes (NRGs) related to DKD tubulointerstitial injury. Results: Eight hundred ninety-eight DEGs were identified from the GSE30122 dataset. A significant module associated with diabetic tubulointerstitial injury overlapped with 15 NRGs. The hub genes, CASP1 and LYZ, were identified as potential biomarkers. Functional enrichment linked these genes with immune cell trafficking, metabolic alterations, and inflammatory responses. NRGs negatively correlated with glomerular filtration rate (GFR) in the Neph v5 database. Immunohistochemistry (IHC) validated increased NRGs in DKD tubulointerstitial injury. Conclusion: Our findings suggest that the CASP1 and LYZ genes may serve as potential diagnostic biomarkers for diabetic tubulointerstitial injury. Furthermore, NRGs involved in diabetic tubulointerstitial injury could emerge as prospective targets for the diagnosis and treatment of DKD.

Targeting Neutrophil Extracellular Trap Formation: Exploring Promising Pharmacological Strategies for the Treatment of Preeclampsia

Neutrophils, which constitute the most abundant leukocytes in human blood, emerge as crucial players in the induction of endothelial cell death and the modulation of endothelial cell responses under both physiological and pathological conditions. The hallmark of preeclampsia is endothelial dysfunction induced by systemic inflammation, in which neutrophils, particularly through the formation of neutrophil extracellular traps (NETs), play a pivotal role in the development and perpetuation of endothelial dysfunction and the hypertensive state. Considering the potential of numerous pharmaceutical agents to attenuate NET formation (NETosis) in preeclampsia, a comprehensive assessment of the extensively studied candidates becomes imperative. This review aims to identify mechanisms associated with the induction and negative regulation of NETs in the context of preeclampsia. We discuss potential drugs to modulate NETosis, such as NF-κβ inhibitors, vitamin D, and aspirin, and their association with mutagenicity and genotoxicity. Strong evidence supports the notion that molecules involved in the activation of NETs could serve as promising targets for the treatment of preeclampsia.

Advanced Immunomodulatory Biomaterials for Therapeutic Applications

The multifaceted biological defense system modulating complex immune responses against pathogens and foreign materials plays a critical role in tissue homeostasis and disease progression. Recently developed biomaterials that can specifically regulate immune responses, nanoparticles, graphene, and functional hydrogels have contributed to the advancement of tissue engineering as well as disease treatment. The interaction between innate and adaptive immunity, collectively determining immune responses, can be regulated by mechanobiological recognition and adaptation of immune cells to the extracellular microenvironment. Therefore, applying immunomodulation to tissue regeneration and cancer therapy involves manipulating the properties of biomaterials by tailoring their composition in the context of the immune system. This review provides a comprehensive overview of how the physicochemical attributes of biomaterials determine immune responses, focusing on the physical properties that influence innate and adaptive immunity. This review also underscores the critical aspect of biomaterial-based immune engineering for the development of novel therapeutics and emphasizes the importance of understanding the biomaterials-mediated immunological mechanisms and their role in modulating the immune system.