DNA of neutrophil extracellular traps promote NF-κB-dependent autoimmunity via cGAS/TLR9 in chronic obstructive pulmonary disease

METTL3‑mediated m6A methylation and its impact on OTUD1 expression in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and chronic inflammation, often exacerbated by cigarette smoke exposure. Ovarian tumor protease domain‑containing protein 1 (OTUD1), a deubiquitinase, has previously been identified as a negative regulator of inflammation through its suppression of NF‑κB signaling. The present study explored the role of OTUD1 in COPD and the regulatory effects of N6‑methyladenosine (m6A) methylation on OTUD1 expression. The expression of OTUD1 in COPD was analyzed using public datasets (GSE38974 and GSE69818). In addition, BEAS‑2B cells were exposed to cigarette smoke extract (CSE) to investigate OTUD1 expression changes. OTUD1 overexpression and knockdown models were also constructed, and the levels of inflammation‑related genes and proteins, inflammatory cytokines and cell pyroptosis were measured using reverse transcription‑quantitative PCR, western blotting, ELISA and flow cytometry. The role of methyltransferase‑like 3 (METTL3)‑mediated m6A methylation in regulating OTUD1 was also examined. Notably, OTUD1 expression was significantly reduced in advanced COPD compared with that in the earlier stage. Furthermore, CSE exposure suppressed OTUD1 expression, which was associated with increased cell pyroptosis and elevated levels of the inflammatory cytokines IL‑1β and IL‑18. OTUD1 overexpression mitigated these effects, indicating its protective role against CSE‑induced cellular damage. Furthermore, METTL3‑mediated m6A methylation inhibited OTUD1 expression, with YTH m6A RNA binding protein 2 (YTHDF2) acting as the reader of this modification. Knockdown of METTL3 or YTHDF2 reduced m6A methylation and restored OTUD1 expression, highlighting a potential mechanism by which cigarette smoke suppresses OTUD1 through enhanced m6A methylation. In conclusion, OTUD1 may serve a protective role in COPD by inhibiting inflammation and reducing cell damage caused by cigarette smoke exposure. The suppression of OTUD1 through METTL3‑mediated m6A methylation and YTHDF2 interaction represents a novel mechanism contributing to COPD pathogenesis, suggesting potential therapeutic targets for mitigating disease progression.

NETosis in myocardial ischemia-reperfusion injury: From mechanisms to therapies (Review)

The present review describes the mechanisms of NETosis and its role in myocardial ischemia-reperfusion injury (MIRI), focusing on the release of neutrophil extracellular traps (NETs) by activated neutrophils. NETs, composed of depolymerized chromatin and granule proteins, are crucial for pathogen entrapment, infection control and immune regulation. However, NET formation, linked to neutrophil death (NETosis), exacerbates MIRI by promoting inflammation and tissue damage. To address therapeutic strategies for NETosis in MIRI, several potential clinically significant approaches were explored, including peptidylarginine deaminase 4 inhibition, DNase therapy, antioxidants, inflammation modulation, and antithrombotic treatments, which not only provide novel diagnostic biomarkers and therapeutic targets in MIRI, but are also expected to improve patient prognosis and advance the development of personalised medicine.

Saturated fatty acid-induced neutrophil extracellular traps contribute to exacerbation and biologic therapy resistance in obesity-related psoriasis

Psoriasis patients who are obese tend to have serious clinical manifestations and poor responses to various biological agents in most cases. However, the mechanisms by which obesity exacerbates psoriasis remain enigmatic. In this study, we found that the abundance of systemic and localized cutaneous neutrophil extracellular traps (NETs) associated with the obesity-induced aggravation of psoriasis was positively correlated with disease severity and that the inhibition of NETs alleviated psoriatic dermatitis in obese mice. Mechanistically, we found that changes in fatty acid composition in obese subjects resulted in the deposition of saturated fatty acids (SFAs), which promoted the release of NETs via the TLR4-MD2/ROS signaling pathway. We further revealed that NETs potentiate IL-17 inflammation, especially γδT17-mediated immune responses, in obesity-exacerbated psoriasis patients. Moreover, SFAs induced a decreased response to anti-IL17A treatment in psoriasis-like mice, whereas the inhibition of NETs improved the beneficial effects of anti-IL17A in psoriasis-like mice with lipid metabolism disorders. Our findings collectively suggest that SFA-induced NETs play a critical role in the exacerbation of obesity-related psoriasis and provide potential new strategies for the clinical treatment of refractory psoriasis patients with lipid metabolism disorders.

Neutrophil extracellular traps activate STING signaling to promote dendritic cell-driven rejection after liver transplantation

PURPOSE

Post-transplant immune rejection affects graft function. Interaction between neutrophil extracellular traps (NETs) with specific immune cells and the specific mechanism in liver transplantation were still unclear.

METHOD

Clinical patients RNA-Seq results were used for GSEA and KEGG analysis. C57BL/6 and C3H mouse models and clinical samples were use to describe the disease phenotype characteristics through multiple immunofluorescence, flow cytometry and etc. Cell co-culture experiments were performed to clarify the mechanism pathway process.

RESULTS

RNA-Seq results analysis indicated that the NETs formation pathway was upregulated. Animal models confirmed that in liver transplant immune rejection status the formation of NETs in situ and peripheral cells increased and the level of cell-free DNA (cf-DNA) in peripheral cells increased. Reactive oxygen species (ROS) as a predisposing factor for NETs accumulated more in immune rejection status and NETs are rich in mitochondrial DNA (mtDNA). NETs promote dendritic cell maturation through STING-related pathways. NETs formation increases in patients with liver transplant immune rejection and is positively correlated with disease severity.

CONCLUSION

We found that NETs can regulate dendritic cell maturation through STING-related pathways after liver transplantation, which may ultimately promote the occurrence of liver transplant rejection, providing a new perspective for clinical diagnosis, treatment and prevention of liver transplant rejection.

Exploring neutrophil extracellular traps: mechanisms of immune regulation and future therapeutic potential

Neutrophil extracellular traps (NETs) are complex, web-like structures consisting of DNA intertwined with antimicrobial proteins, which neutrophils release upon immune activation. These structures play a crucial role in pathogen elimination, particularly in infectious diseases. However, their involvement in various pathological conditions is multifaceted and context-dependent, while NETs contribute to host defense against infections, they can also exacerbate sterile inflammation, autoimmune disorders, and tumor progression. This review provides a comprehensive analysis of the molecular mechanisms governing NET formation and examines their interactions with immune cells, emphasizing how these interactions shape immune responses and drive disease dynamics. Furthermore, it explores ongoing clinical trials and emerging therapeutic strategies targeting NETs, offering critical insights into their potential translational applications in clinical practice.

Sequential nanoparticle therapy targeting neutrophil hyperactivation to prevent neutrophil-induced pulmonary fibrosis

BACKGROUND

Pulmonary fibrosis, a major complication of severe COVID-19 and post-acute sequelae of SARS-CoV-2 infection (PASC), is driven by excessive neutrophil activation and the formation of neutrophil extracellular trap (NET).

RESULTS

This study presents a sequential nanoparticle-based therapy combining DNase-I-loaded polydopamine nanoparticles (DNase-I@PDA NPs) with Sivelestat-encapsulated PLGA nanoparticles (Siv@PLGA NPs) to target both NETs and neutrophil elastase (NE) activity. DNase-I@PDA NPs were aerosolized to the lungs, facilitating NET clearance and reducing the fibrotic microenvironment, followed by intravenous administration of Siv@PLGA NPs to inhibit NE activity and prevent neutrophil hyperactivation. In a murine model of lipopolysaccharide (LPS)-induced pulmonary fibrosis, this dual approach significantly decreased fibrotic lesions, collagen deposition, and myofibroblast activation. Notably, treatment with the nanoparticles led to substantial improvements in pulmonary function. In neutrophils isolated from COVID-19 patients, the combined nanoparticle therapy reduced circulating cell-free DNA, NET, NE, and myeloperoxidase (MPO) levels, while enhancing neutrophil viability and reducing inflammatory responses.

CONCLUSIONS

These findings highlight the efficacy of DNase-I@PDA NPs and Siv@PLGA NPs in addressing both acute inflammation and chronic fibrosis by simultaneously targeting NET formation and neutrophil hyperactivation. This dual nanoparticle therapy represents a promising clinical strategy for treating COVID-19-associated pulmonary complications, including PASC, by preventing long-term fibrotic progression and promoting lung recovery.

On the Ocean of Biomarkers for the Precise Diagnosis and Prognosis of Lung Diseases

Bronchoalveolar lavage fluid (BALF) has long been used for diagnosing various lung diseases through its cellular components. However, the clinical utility of biomolecules in the BALF remains largely unexplored. Recently, mass spectrometry-based proteomics has been applied to profile the BALF proteomes to identify novel biomarkers for lung diseases. This review discusses the current progress in the field of BALF proteomics and highlights its potential as a valuable source of biomarkers for different lung diseases. Additionally, we explored the latest advancements and findings from BALF studies. Finally, we address the current limitations and propose future directions and research opportunities to advance the study of BALF.

In vitro study: HIF-1α-dependent glycolysis enhances NETosis in hypoxic conditions

Background

Hypoxia plays a pivotal role in modulating immune responses, especially in neutrophils, which are essential components of the innate immune system. Hypoxia-inducible factor (HIF)-1α, a key transcription factor in hypoxic adaptation, regulates cellular metabolism and inflammatory responses. However, the impact of HIF-1α-dependent glycolysis on the formation of neutrophil extracellular traps (known as NETosis) under hypoxic conditions remains unclear.

Methods

We employed two established neutrophil models, neutrophils isolated from human whole blood and DMSO-induced dHL-60 cells, to explore the role of HIF-1α in regulating glycolysis and its influence on NETosis under hypoxic conditions. We utilized western blotting, immunofluorescence staining, ELISA, and flow cytometry to evaluate the expression of key glycolytic enzymes and NETosis markers under hypoxia. Additionally, the effects of inhibiting HIF-1α with LW6 and blocking the glycolytic pathway with Bay-876 were investigated.

Results

HIF-1α-dependent glycolysis, through the upregulation of key glycolytic enzymes, significantly enhances NETosis under hypoxic conditions. Pharmacological inhibition of HIF-1α with LW6 and glycolytic blockade with Bay-876 markedly reduced NETosis, underscoring the crucial role of metabolic reprogramming in neutrophil function during hypoxia.

Conclusion

This study provides novel insights into the interplay between metabolic reprogramming and NETosis in response to hypoxic stress. We identify HIF-1α-dependent glycolysis as a key driver of NETs formation, advancing our understanding of the mechanisms underlying hypoxia-related inflammatory diseases. These findings also suggest that targeting metabolic pathways may offer potential therapeutic strategies for modulating immune responses in hypoxia-associated disorders.

Regulated cell death and DAMPs as biomarkers and therapeutic targets in normothermic perfusion of transplant organs. Part 2: implementation strategies

This Part 2 of a bipartite review commences with the delineation of a conceptual model outlining the fundamental role of injury-induced regulated cell death (RCD) in the release of DAMPs that drive innate immune responses involved in early inflammation-related allograft dysfunction and alloimmune-mediated allograft rejection. In relation to this topic, the focus is on the divergent role of donor and recipient dendritic cells (DCs), which become immunogenic in the presence of DAMPs to regulate alloimmunity, but in the absence of DAMPs acquire tolerogenic properties to promote allotolerance. With respect to this scenario, proposals are then made for leveraging RCD and DAMPs as biomarkers during normothermic regional perfusion (NRP) and normothermic machine perfusion (NMP) of transplant organs from DCD donors, a strategy poised to significantly enhance current policies for assessing donor organ quality. The focus is then on the ambitious goal to target RCD and DAMPs therapeutically during NRP and NMP, aiming to profoundly suppress subsequently early allograft inflammation and alloimmunity in the recipient. This strategic approach seeks to prevent the activation of intragraft innate immune cells including DCs during donor organ reperfusion in the recipient, which is driven by ischemia/reperfusion injury-induced DAMPs. In this context, available inhibitors of various types of RCD, as well as scavengers and inhibitors of DAMPs are highlighted for their promising therapeutic potential in NRP and NMP settings, building on their proven efficacy in other experimental disease models. If successful, this kind of therapeutic intervention should also be considered for application to organs from DBD donors. Finally, drawing on current global insights into the critical role of RCD and DAMPs in driving innate inflammatory and (allo)immune responses, targeting their inhibition and/or prevention during normothermic perfusion of transplant organs from DCD donors - and potentially DBD donors - holds the transformative potential to not only alleviate transplant dysfunction and suppress allograft rejection but also foster allograft tolerance.

Regulated cell death and DAMPs as biomarkers and therapeutic targets in normothermic perfusion of transplant organs. Part 1: their emergence from injuries to the donor organ

This Part 1 of a bipartite review commences with a succinct exposition of innate alloimmunity in light of the danger/injury hypothesis in Immunology. The model posits that an alloimmune response, along with the presentation of alloantigens, is driven by DAMPs released from various forms of regulated cell death (RCD) induced by any severe injury to the donor or the donor organ, respectively. To provide a strong foundation for this review, which examines RCD and DAMPs as biomarkers and therapeutic targets in normothermic regional perfusion (NRP) and normothermic machine perfusion (NMP) to improve outcomes in organ transplantation, key insights are presented on the nature, classification, and functions of DAMPs, as well as the signaling mechanisms of RCD pathways, including ferroptosis, necroptosis, pyroptosis, and NETosis. Subsequently, a comprehensive discussion is provided on major periods of injuries to the donor or donor organs that are associated with the induction of RCD and DAMPs and precede the onset of the innate alloimmune response in recipients. These periods of injury to donor organs include conditions associated with donation after brain death (DBD) and donation after circulatory death (DCD). Particular emphasis in this discussion is placed on the different origins of RCD-associated DAMPs in DBD and DCD and the different routes they use within the circulatory system to reach potential allografts. The review ends by addressing another particularly critical period of injury to donor organs: their postischemic reperfusion following implantation into the recipient-a decisive factor in determining transplantation outcome. Here, the discussion focuses on mechanisms of ischemia-induced oxidative injury that causes RCD and generates DAMPs, which initiate a robust innate alloimmune response.

Targeting neutrophil extracellular traps in cancer progression and metastasis

Neutrophils serve as pivotal effectors and regulators of the intricate immune system. Their contributions are indispensable, encompassing the obliteration of pathogens and a significant role in both cancer initiation and progression. Conversely, malignancies profoundly affect neutrophil activity, maturation, and lifespans. Cancer cells manipulate their biology to enhance or suppress the key functions of neutrophils. This manipulation is one of the most remarkable defensive mechanisms used by neutrophils, including the formation of neutrophil extracellular traps (NETs). NETs are filamentous structures comprising DNA, histones, and proteins derived from cytotoxic granules. In this review, we discuss the bidirectional interplay in which cancer elicits NET formation, and NETs concurrently facilitate cancer progression. Here, we discuss how vascular dysfunction and thrombosis induced by neutrophils and NETs contribute to an elevated risk of mortality from cardiovascular complications in patients with cancer. Ultimately, we propose a series of therapeutic strategies that hold promise for effectively targeting NETs in clinical settings.

Mitochondrial DNA signals driving immune responses: Why, How, Where?

There has been a recent expansion in our understanding of DNA-sensing mechanisms. Mitochondrial dysfunction, oxidative and proteostatic stresses, instability and impaired disposal of nucleoids cause the release of mitochondrial DNA (mtDNA) from the mitochondria in several human diseases, as well as in cell culture and animal models. Mitochondrial DNA mislocalized to the cytosol and/or the extracellular compartments can trigger innate immune and inflammation responses by binding DNA-sensing receptors (DSRs). Here, we define the features that make mtDNA highly immunogenic and the mechanisms of its release from the mitochondria into the cytosol and the extracellular compartments. We describe the major DSRs that bind mtDNA such as cyclic guanosine-monophosphate-adenosine-monophosphate synthase (cGAS), Z-DNA-binding protein 1 (ZBP1), NOD-, LRR-, and PYD- domain-containing protein 3 receptor (NLRP3), absent in melanoma 2 (AIM2) and toll-like receptor 9 (TLR9), and their downstream signaling cascades. We summarize the key findings, novelties, and gaps of mislocalized mtDNA as a driving signal of immune responses in vascular, metabolic, kidney, lung, and neurodegenerative diseases, as well as viral and bacterial infections. Finally, we define common strategies to induce or inhibit mtDNA release and propose challenges to advance the field.

Proteogenomic verifies targets underlying erythromycin alleviate neutrophil extracellular traps-induced inflammation

BACKGROUND

Neutrophil Extracellular Traps (NETs) are closely related to the progression of inflammation in Chronic Obstructive Pulmonary Disease (COPD). Erythromycin (EM) has been shown to inhibit inflammation in COPD, but its molecular mechanisms is still unclear. The aim of our study is investigate the molecular mechanisms of EM's anti-inflammatory effects in NETs-induced inflammation.

METHODS

Transcriptomics and proteomics data were obtained from U937 cells treated with NETs and EM. Differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were identified using R software. Pathway enrichment analyses, were employed to identify inflammation-related pathways. Cytoscape were utilized to construct network of hub targets regulated by EM which related with oxidative stress and inflammation. Additionally, Cytoscape and STRING were used to construct protein-protein interaction (PPI) network of key targets regulated by EM. The expression levels of key targets were further confirmed through WB and PCR experiments.

RESULTS

Both transcriptomics and proteomics indicate that EM decrease NETs -induced AKT1 expression. Enrichment analysis of DEGs and DEPs reveal multiple common pathways involved in EM's regulation inflammation, including the PI3K/AKT pathway, response to oxidative stress, IKK/NF-κB signaling and PTEN signaling pathway. Nine key targets in PI3K/AKT-related inflammatory pathways regulated by EM and ten targets of EM-regulated oxidative stress were identified. WB and PCR results confirmed that EM reversing the NETs-induced inflammation by modulating the activity of these targets. Furthermore, clinical samples and vitro experiments confirm that EM alleviates NETs-induced glucocorticoid resistance via inhibiting PI3K/AKT, thereby repressing inflammation.

CONCLUSIONS

Our study provides a comprehensive proteogenomic characterization of how EM alleviates NET-related inflammation, and identify PI3K/AKT play a critical role in the mechanism by which EM inhibits inflammation.

Transcriptomic and metabolomic insights into neutrophil activity in COPD complicated by metabolic syndrome

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) frequently coexists with metabolic syndrome (MS), compounding its impact on patients' health and quality of life. This study aimed to elucidate the immune and metabolic response characteristics in COPD patients with and without MS.

METHODS

A total of 11,315 COPD patients admitted to the Department of Respiratory and Critical Care Medicine at the Third People's Hospital of Chengdu between January 1, 2013, and May 1, 2023, were selected. Multivariate logistic regression was conducted to identify the risk factors for acute exacerbation of chronic obstructive pulmonary disease. Moreover, from this cohort, 30 patients (18 with COPD and 12 with COPD-MS) were recruited for a further study to investigate the underlying mechanisms of COPD and COPD-MS. Blood samples were collected from these participants to perform transcriptomic and metabolomic analyses, aiming to explore the differences in immune responses and metabolic alterations between the two groups.

RESULTS

Our findings indicate a significant enhancement of neutrophil-mediated immune responses in COPD-MS patients. Transcriptomic analysis revealed 327 differentially expressed genes (DEGs) significantly involved in neutrophil-mediated immunity. Key metabolic pathways were disrupted, with 39 differential metabolites identified. Notably, metabolites, such as L-homoarginine and diethanolamine, which were elevated in COPD-MS patients, showed strong correlations with DEGs involved in neutrophil pathways and immune checkpoint regulation. The study also found decreased levels of IL4 and IL5RA in COPD-MS patients, suggesting a shift from Th2 to Th1 inflammatory responses, potentially contributing to glucocorticoid resistance.

CONCLUSIONS

COPD patients with metabolic syndrome exhibit a heightened neutrophil-mediated inflammatory response and significant metabolic disturbances, which underscores the need for precise therapeutic strategies targeting both metabolic and inflammatory pathways to improve patient outcomes and manage COPD-MS complexities effectively.

Multifunctional Boron-based 2D Nanoplatforms Ameliorate Severe Respiratory Inflammation by Targeting Multiple Inflammatory Mediators

Effective management of serious respiratory diseases, such as asthma and recalcitrant rhinitis, remains a global challenge. Here, it is shown that induced sputum supernatants (ISS) from patients with asthma contain higher levels of cell-free DNA (cfDNA) compared to that of healthy volunteers. Although cfDNA scavenging strategies have been developed for inflammation modulation in previous studies, this fall short in clinical settings due to the excessive neutrophil extracellular trap (NET) formation, reactive oxygen and nitrogen species (RONS) and bacterial infections in injured airway tissues. Based on this, a multifunctional boron-based 2D nanoplatform B-PM is designed by coating boron nanosheets (B-NS) with polyamidoamine generation 1 (PG1) dendrimer, which can simultaneously target cfDNA, NETs, RONS, and bacteria. The effects of B-PM in promoting mucosal repair, reducing airway inflammation, and mucus production have been demonstrated in model mice, and the therapeutic effect is superior to dexamethasone. Furthermore, flow cytometry with clustering analysis and transcriptome analysis with RNA-sequencing are adopted to comprehensively evaluate the in vivo anti-inflammation therapeutic effects. These findings emphasize the significance of a multi-targeting strategy to modulate dysregulated inflammation and highlight multifunctional boron-based 2D nanoplatforms for the amelioration of respiratory inflammatory diseases.

Astragaloside IV- loaded biomimetic nanoparticles target IκBα to regulate neutrophil extracellular trap formation for sepsis therapy

This study explored the novel mechanism of Astragaloside IV (As) in treating sepsis and its application through a biomimetic nano-delivery system (As@ZM). Sepsis, a condition of organ dysfunction caused by an abnormal host response to infection, poses a significant threat to global health due to its high mortality rate. Our findings revealed a new mechanism for As in treating sepsis, which involved the reduction of neutrophil extracellular traps (NETs) release, potentially related to As binding with IκBα to inhibit the activation of the NF-κB pathway. As treated neutrophils also improved the immune microenvironment by crosstalk with endothelial cells and lung epithelial cells. However, the stability and bioavailability of As limited its clinical application. To address this issue, we had developed a ZIF-8-based nano-delivery system that achieved targeted delivery through neutrophil membrane coating, significantly enhancing the therapeutic efficacy of As. The innovative design of As@ZM offered a new strategy for sepsis treatment, with the potential to improve clinical outcomes.

Qingke Pingchuan granules alleviate airway inflammation in COPD exacerbation by inhibiting neutrophil extracellular traps in mice

BACKGROUND

Chronic obstructive pulmonary disease (COPD) imposes a significant global health and socioeconomic burden. Exacerbations of COPD (ECOPD), characterized by heightened airway inflammation and mucus hypersecretion, adversely affect patient health and accelerate disease progression. Qingke Pingchuan (QKPC) granules, a formulation from Traditional Chinese Medicine initially prescribed for acute bronchitis, have shown unexplored potential in ECOPD management, with mechanisms of action yet to be clarified.

PURPOSE

This study investigates the therapeutic effects of QKPC in a mouse model of ECOPD, focusing on underlying molecular mechanisms.

METHODS

COPD was induced in mice through chronic cigarette smoke (CS) exposure, followed by intratracheal administration of Pseudomonas aeruginosa lipopolysaccharide (LPS) to trigger exacerbation, after which mice were treated with QKPC granules. Major compounds in QKPC were identified via UHPLC-QE-MS, and high-throughput RNA sequencing of lung tissue samples identified differentially expressed genes. Transcriptomic data were integrated with network pharmacology analysis to pinpoint potential pathways, bioactive compounds, and target genes through which QKPC might attenuate ECOPD. Molecular docking, protein-small molecule binding assays, and in vitro analyses further validated interactions between key compounds and target genes, shedding light on plausible signaling pathways.

RESULTS

QKPC treatment led to significant reductions in airway leukocyte infiltration and goblet cell metaplasia in CS- and LPS-exposed mice, accompanied by decreased levels of inflammatory cytokines (IL-6, IL-1β, CXCL1, and TNF-α) and mucin MUC5AC in bronchoalveolar lavage fluid. The integrative transcriptomic and network pharmacology analysis identified the neutrophil extracellular trap (NET) formation pathway as a key mechanism underlying QKPC's protective effect against ECOPD. In vitro assays demonstrated that epigallocatechin-3-gallate (EGCG) and quercetin, two important bioactive compounds in QKPC, significantly inhibited NETosis induced by cigarette smoke extract (CSE) plus LPS in human neutrophils. The two compounds were found to interact directly with the reactive oxidative species (ROS)-generating enzyme NOX2 and its regulatory subunit p47phox. Subsequent in vitro studies further confirmed EGCG and quercetin's capacity to reduce ROS production and downregulate NOX2 and p47phox protein levels in neutrophils stimulated with CSE and LPS. Additionally, in vivo studies confirmed QKPC's efficacy in reducing NET formation, oxidative stress, and NOX2/p47phox protein expression in the lung tissue of ECOPD mice.

CONCLUSION

These findings suggest that QKPC granules alleviate airway inflammation in ECOPD, potentially through inhibition of pulmonary NET formation via the NOX2/p47phox-ROS pathway, underscoring their potential therapeutic application for ECOPD management in clinical settings.

Construction of a neutrophil extracellular trap formation-related gene model for predicting the survival of lung adenocarcinoma patients and their response to immunotherapy

Background

Lung adenocarcinoma (LUAD) is associated with high morbidity and mortality rates. Increasing evidence indicates that neutrophil extracellular traps (NETs) play a critical role in tumor progression, metastasis and immunosuppression in the LUAD tumor microenvironment (TME). Nevertheless, the use of NET formation-related genes (NFRGs) to predict LUAD patient survival and response to immunotherapy has not been explored. Therefore, this study aimed to construct a NFRGs-based prognostic signature for stratifying LUAD patients and informing individualized management strategies.

Methods

The cell composition of the LUAD TME was investigated using the single-cell sequencing data in Single-Cell Lung Cancer Atlas (LuCA). NFRGs were identified to construct a prognostic signature based on The Cancer Genome Atlas (TCGA) cohort which was validated in the Gene Expression Omnibus (GEO) dataset. The univariate Cox and least absolute shrinkage and selection operator (LASSO) Cox regression models, receiver operating characteristic (ROC) and Brier Score were applied to assess the prognostic model. A nomogram was established to facilitate the clinical application of the risk score. The Estimation of STromal and Immune cells in MAlignant Tumor tissues (ESTIMATE) and Tumor Immune Dysfunction and Exclusion (TIDE) algorithm were utilized to assess the TME and predict immunotherapy response. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was applied to quantify the expression levels of four NFRGs in LUAD paired tissue samples.

Results

Single‑cell RNA sequence analysis showed the importance of neutrophils in LUAD TME. We developed and validated a 4-NFRG (CAT, CTSG, ENO1, TLR2) prognostic signature based on TCGA and GEO cohorts, which stratified patients into high-risk and low-risk groups. Univariate and multivariate analyses showed that our risk model could independently predict the survival of LUAD patients. Patients in the low-risk group exhibited a more active immune microenvironment, lower TIDE scores, lower half-maximal inhibitory concentration (IC50) values and higher immune checkpoint molecule expression. Our risk signature could serve as a biomarker for predicting immunotherapeutic benefits.

Conclusions

We developed a novel prognostic signature for LUAD patients based on NFRGs and emphasized the critical role of this signature in predicting LUAD patient survival and immunotherapy response.

Neutrophil diversity and function in health and disease

Neutrophils, the most abundant type of granulocyte, are widely recognized as one of the pivotal contributors to the acute inflammatory response. Initially, neutrophils were considered the mobile infantry of the innate immune system, tasked with the immediate response to invading pathogens. However, recent studies have demonstrated that neutrophils are versatile cells, capable of regulating various biological processes and impacting both human health and disease. Cytokines and other active mediators regulate the functional activity of neutrophils by activating multiple receptors on these cells, thereby initiating downstream signal transduction pathways. Dysfunctions in neutrophils and disruptions in neutrophil homeostasis have been implicated in the pathogenesis of numerous diseases, including cancer and inflammatory disorders, often due to aberrant intracellular signaling. This review provides a comprehensive synthesis of neutrophil biological functions, integrating recent advancements in this field. Moreover, it examines the biological roles of receptors on neutrophils and downstream signaling pathways involved in the regulation of neutrophil activity. The pathophysiology of neutrophils in numerous human diseases and emerging therapeutic approaches targeting them are also elaborated. This review also addresses the current limitations within the field of neutrophil research, highlighting critical gaps in knowledge that warrant further investigation. In summary, this review seeks to establish a comprehensive and multidimensional model of neutrophil regulation, providing new perspectives for potential clinical applications and further research.

Integrated respiratory toxicity of municipal wastewater to human bronchial epithelial cells and 3D bronchospheres

Respiratory symptoms have been reported in wastewater treatment workers and residents living close to sewage treatment plant. However, toxicological research about the respiratory hazards of municipal wastewater is scarce. The present study aims to gain insight into the comprehensive respiratory hazards induced by the contaminant mixtures in municipal wastewater. The integrated respiratory hazards of effluents from four secondary wastewater treatment plants (SWTPs), a tertiary wastewater treatment plant (TTP), and a constructed wetland (CW) were evaluated using normal human bronchial epithelial cells (NHBE) bioassay, and toxicity reduction efficiency of various treatment techniques was analyzed. Effluents caused cytotoxicity, oxidative damage, inflammation response with the increased levels of IL-6 and CXCL8, and impaired barrier integrity with decreased expressions of ZO-1 and occludin in NHBE. Further, the effluents inhibited the development of 3D bronchospheres, increased irregular surface and cell debris, and suppressed the formation of luminal structures. TTP E effluent significantly increased the expression of MUC5AC in bronchospheres. The integrated biomarker response (IBR) of the influent was removed by 40.2% at SWTPs, 18.2% at TTP, and 36.6% at CW, respectively. The IBR of the final effluents from SWTPs, TTP, and CW were 7.2, 7.7, and 7.7, respectively. Significant correlation with toxicity biomarkers was frequently observed for stearyl alcohol, o-cresol, phenanthrene, butylated hydroxytoluene, and dimethyl phthalate. The present study provided human relevant evidence concerning the adverse respiratory effects associated with discharge. The necessity for deep water treatment, performance optimization, and the potential means were suggested for improving water quality and protecting respiratory health.

A biomimic anti-neuroinflammatory nanoplatform for active neutrophil extracellular traps targeting and spinal cord injury therapy

Traumatic spinal cord injury (SCI) always leads to severe neurological deficits and permanent damage. Neuroinflammation is a vital process of SCI and have become a promising target for SCI treatment. However, the neuroinflammation-targeted therapy would hinder the functional recovery of spinal cord and lead to the treatment failure. Herein, a biomimic anti-neuroinflammatory nanoplatform (DHCNPs) was developed for active neutrophil extracellular traps (NETs) targeting and SCI treatment. The curcumin-loaded liposome with the anti-inflammatory property acted as the core of the DHCNPs. Platelet membrane and neutrophil membrane were fused to form the biomimic hybrid membrane of the DHCNPs for hijacking neutrophils and neutralizing the elevated neutrophil-related proinflammatory cytokines, respectively. DNAse I modification on the hybrid membrane could achieve NETs degradation, blood spinal cord barrier, and neuron repair. Further studies proved that the DHCNPs could reprogram the multifaceted neuroinflammation and reverse the SCI process via nuclear factor kappa-B (NF-κB) pathway. We believe that the current study provides a new perspective for neuroinflammation inhibition and may shed new light on the treatment of SCI.