The role of neutrophil extracellular traps in acute lung injury

Aerosol inhalation of rhIL-10 improves acute lung injury in mice by affecting pulmonary neutrophil phenotypes through neutrophil-platelet aggregates

This study investigates the therapeutic effects of recombinant human IL-10 (rhIL-10) administered via aerosol inhalation in acute lung injury (ALI), with a particular focus on neutrophils. It explores how rhIL-10, in the presence of platelets, modulates neutrophil polarization to ameliorate acute lung injury. Initially, the ALI model established in mice demonstrated that aerosol inhalation of rhIL-10 significantly mitigated the cytokine storm in the lungs, reduced pulmonary edema, and alleviated histopathological damage to lung tissue. Additionally, rhIL-10 administration was found to decrease neutrophil infiltration and platelet activation in the lungs of mice, inhibiting the formation of platelet-neutrophil aggregates (PNAs) and promoting the differentiation of neutrophils toward an anti-inflammatory phenotype in the presence of platelets. Subsequently, primary neutrophils and platelets were isolated from mouse bone marrow and blood to explore the underlying mechanisms. The results indicated that rhIL-10 promotes the expression of the signal transducer and activator of transcription 3 (STAT3) and the suppressor of cytokine signaling 3 (SOCS3) in neutrophils while inhibiting the activation of the nuclear factor kappa B (NF-κB) and the NF-κB inhibitor (IκB), which in turn enhances CD40 expression. This interaction facilitates the formation of PNAs and influences neutrophil phenotype differentiation. Furthermore, the application of the STAT3 phosphorylation inhibitor Stattic and CD40 antibody in vivo provided further validation of this potential mechanism. In conclusion, these results indicate that aerosol inhalation of rhIL-10 effectively ameliorates ALI. The underlying mechanism may involve the modulation of the neutrophil STAT/SOCS-IκB/NF-κB-CD40 signaling pathway, promoting interactions between neutrophils and platelets that facilitate the differentiation of neutrophils toward an anti-inflammatory phenotype.

Targeting ferroptosis offers therapy choice in sepsis-associated acute lung injury

Sepsis-associated acute lung injury (SALI) is a common complication of sepsis, consisting of a dysfunctional host response to infection-mediated heterogenous complexes. SALI is reported in up to 50 % of patients with sepsis and causes poor outcomes. Despite high incidence, there is a lack of understanding in its pathogenesis and optimal treatment. A better understanding of the molecular mechanisms underlying SALI may help produce better therapeutics. The effects of altered cell-death mechanisms, such as non-apoptotic regulated cell death (RCD) (i.e., ferroptosis), on the development of SALI are beginning to be discovered, while targeting ferroptosis as a meaningful target in SALI is increasingly being recognized. Here, we outline how a susceptible lung alveoli may develop SALI. Then we discuss the general mechanisms underlying ferroptosis, and how it contributes to SALI. We then outline the chemical structures of the emerging agents or compounds that can protect against SALI by inhibiting ferroptosis, summarizing their potential pharmacological effects. Finally, we highlight key limitations and possible strategies to overcome them. This review suggests that a detailed mechanistic and biological understanding of ferroptosis can foster the development of pharmacological antagonists in the treatment of SALI.

Squaraine-Peptide Conjugates as Efficient Reporters of Neutrophil Extracellular Traps-Mediated Chronic Inflammation

The excessive and uncontrolled release of neutrophil extracellular traps (NETs) is increasingly linked to the pathogenesis of various inflammatory diseases, cardiovascular disorders, and cancers. Real-time, non-invasive detection of NETs is crucial for understanding their role in disease progression and developing targeted therapies. Current NETs detection methods often lack the necessary specificity and resolution, particularly in vivo and ex vivo settings. To address this, we have developed novel near-infrared squaraine-peptide conjugates by rational molecular design as reporters of NETosis by targeting the protease activity of neutrophil elastase (NE). These self-quenching, cell-impermeable probes enable the precise real-time detection and imaging of NETs. The Förster resonance energy transfer (FRET)-based probe, Hetero-APA, demonstrated high specificity in detecting NETs in vitro and in vivo, generating strong fluorescence in NETs-rich environments. To overcome the limitations of FRET-based probes for ex vivo imaging, we designed SQ-215-NETP, a non-FRET-based probe that covalently binds to the NE. SQ-215-NETP achieved an unprecedented imaging resolution of 90 nm/pixel in human coronary thrombi, marking the first report of such high resolution with a low molecular weight probe. Additionally, SQ-215-NETP effectively detected NETs by flow cytometry. These results highlight the potential of these probes in NETosis detection, offering promising tools for enhanced diagnostics and therapeutic strategies in managing NET-mediated inflammatory diseases and cancers.

Neutrophil heterogeneity and plasticity: unveiling the multifaceted roles in health and disease

Neutrophils, the most abundant circulating leukocytes, have long been recognized as key players in innate immunity and inflammation. However, recent discoveries unveil their remarkable heterogeneity and plasticity, challenging the traditional view of neutrophils as a homogeneous population with a limited functional repertoire. Advances in single-cell technologies and functional assays have revealed distinct neutrophil subsets with diverse phenotypes and functions and their ability to adapt to microenvironmental cues. This review provides a comprehensive overview of the multidimensional landscape of neutrophil heterogeneity, discussing the various axes along which diversity manifests, including maturation state, density, surface marker expression, and functional polarization. We highlight the molecular mechanisms underpinning neutrophil plasticity, focusing on the complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications that shape neutrophil responses. Furthermore, we explore the implications of neutrophil heterogeneity and plasticity in physiological processes and pathological conditions, including host defense, inflammation, tissue repair, and cancer. By integrating insights from cutting-edge research, this review aims to provide a framework for understanding the multifaceted roles of neutrophils and their potential as therapeutic targets in a wide range of diseases.

Network pharmacology-based strategy to reveal Acacetin against lipopolysaccharide-induced lung injury

BACKGROUND

Acacetin, a flavonoid isolated from Agastache rugosa, exhibits diverse biological activities, such as anti-tumor, anti-inflammatory and antioxidant activities. Its role in treating Lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains incompletely illuminated.

OBJECTIVE

To explore the potential molecular mechanisms of Acacetin in alleviating ALI.

MATERIALS & METHODS

The network pharmacological approach was employed to screen the target genes and pathways of Acacetin. Lung injury was analyzed by Hematoxylin-Eosin (H&E) staining. Bronchoalveolar lavage fluid, serum and lung tissues were collected to detect the levels of proinflammatory cytokines and oxidative stress markers. Immunofluorescence and RT-qPCR experiments were used to observe the expression of CD45, COX2, Ly6G, and related-target proteins. In vitro, RAW264.7 macrophages were stimulated with LPS and treated with AMPK siRNA or an AMPK inhibitor Coumpound C to verify the role of AMPK/nuclear factor erythroid 2-related factor 2 (Nrf2)/high-mobility group box 1 (HMGB1) signaling in Acacetin-mediated alleviation of ALI.

RESULTS

Network data revealed that Acacetin could regulate HMGB1, AMPK, Nrf2, and IL-6. In vivo, Acacetin reversed pathological damage and the release of inflammatory factors, and alleviated oxidative stress and immune cell infiltration in ALI development. Acacetin remarkably upregulated the expression of AMPK and Nrf2, accompanied by HMGB1 downregulation. In vitro, inhibiting AMPK reversed the effects of Acacetin in LPS-treated RAW264.7, due to inactivation of AMPK/Nrf2/HMGB1 pathway.

CONCLUSION

The combination of network pharmacology and experimental studies revealed the role of Acacetin in improving ALI via the AMPK/Nrf2/HMGB1 signaling axis, which provided new insights into the treatment of ALI with Acacetin as a candidate drug.

Cordyceps militaris solid medium extract alleviates lipopolysaccharide-induced acute lung injury via regulating gut microbiota and metabolism

Acute lung injury (ALI) is a common respiratory disease, Cordycepin has been reported to reduce ALI, which is an effective component in Cordyceps militaris solid medium extract (CMME). Therefore, we aimed to explore the alleviating effect and mechanism of CMME on ALI. This study evaluated the effect of CMME on lipopolysaccharide (LPS)-induced ALI mice by analyzing intestinal flora and metabolomics to explore its potential mechanism. We assessed pulmonary changes, inflammation, oxidative stress, and macrophage and neutrophil activation levels, then we analyzed the gut microbiota through 16S rRNA and analyzed metabolomics profile by UPLC-QTOF/MS. The results showed that CMME treatment improved pulmonary injury, reduced inflammatory factors and oxidative stress levels, and decreased macrophage activation and neutrophil recruitment. The 16S rRNA results revealed that CMME significantly increased gut microbiota richness and diversity and reduced the abundance of Bacteroides compared with Mod group significantly. Metabolic analysis indicated that CMME reversed the levels of differential metabolites and may ameliorate lung injury through purine metabolism, nucleotide metabolism, and bile acid (BA) metabolism, and CMME did reverse the changes of BA metabolites in ALI mice, and BA metabolites were associated with inflammatory factors and intestinal flora. Therefore, CMME may improve lung injury by regulating intestinal flora and correcting metabolic disorders, providing new insights into its mechanism of action.

Recent Advances in Pathogenesis and Anticoagulation Treatment of Sepsis-Induced Coagulopathy

Coagulopathy in sepsis is common and is associated with high mortality. Although immunothrombosis is necessary for infection control, excessive thrombus formation can trigger a systemic thrombo-inflammatory response. Immunothrombosis plays a core role in sepsis-induced coagulopathy, and research has revealed a complex interplay between inflammation and coagulation. Different mechanisms underlying sepsis-related coagulopathy are discussed, including factors contributing to the imbalance of pro- and anticoagulation relevant to endothelial cells. The potential therapeutic implications of anticoagulants on these mechanisms are discussed. This review contributes to our understanding of the pathogenesis of coagulopathy in patients with sepsis. Recent studies suggest that endothelial cells play an important role in immunoregulation and hemostasis. Meanwhile, the non-anticoagulation effects of anticoagulants, especially heparin, which act in the pathogenesis of coagulopathy in septic patients, have been partially revealed. We believe that further insights into the pathogenesis of sepsis-induced coagulopathy will help physicians evaluate patient conditions effectively, leading to advanced early recognition and better decision-making in the treatment of sepsis.

The β Common Cytokine Receptor Family Reveals New Functional Paradigms From Structural Complexities

Cytokines are small proteins that are critical for controlling the growth and activity of hematopoietic cells by binding to cell surface receptors and transmitting signals across membranes. The β common (βc) cytokine receptor family, consisting of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-3, and IL-5 cytokine receptors, is an architype of the heterodimeric cytokine receptor systems. We now know that signaling by cytokine receptors is not always an "all or none" phenomenon. Subtle alterations of the cytokine:receptor complex can result in differential or selective signaling and underpin a variety of diseases including chronic inflammatory conditions and cancers. Structural biology techniques, such as X-ray crystallography and cryo-electron microscopy alongside cell biology studies, are providing detailed insights into cytokine receptor signaling. Recently, we found that the IL-3 receptor ternary complex forms higher-order assemblies, like those found earlier for the GM-CSF receptor, and demonstrated that functionally distinct biological signals arise from different IL-3 receptor oligomeric assemblies. As we enhance our understanding of the structural nuances of cytokine-receptor interactions, we foresee a new era of theranostics whereby structurally guided mechanism-based manipulation of cytokine signaling through rational/targeted protein engineering will harness the full potential of cytokine biology for precision medicine.

A novel biomarker of COVI-19: MMP8 emerged by integrated bulk RNAseq and single-cell sequencing

COVID-19 has been emerging as the most influential illness which has caused great costs to the heath of population and social economy. Sivelestat sodium (SS) is indicated as an effective cure for lung dysfunction, a characteristic symptom of COVID-19 infection, but its pharmacological target is still unclear. Therefore, a deep understanding of the pathological progression and molecular alteration is an urgent issue for settling the diagnosis and therapy problems of COVID-19. In this study, the bulk ribonucleic acid sequencing (RNA-seq) data of healthy donors and non-severe and severe COVID-19 patients were collected. Then, target differentially expressed genes (DEGs) were screened through integrating sequencing data and the pharmacological database. Besides, with the help of functional and molecular interaction analyses, the potential effect of target gene alteration on COVID-19 progression was investigated. Single-cell sequencing was performed to evaluate the cell distribution of target genes, and the possible interaction of gene-positive cells with other cells was explored by intercellular ligand-receptor pattern analysis. The results showed that matrix metalloproteinase 8 (MMP8) was upregulated in severe COVID-19 patients, which was also identified as a targeting site to SS. Additionally, MMP8 took a core part in the regulatory interaction network of the screened DEGs in COVID-19 and was dramatically correlated with the inflammatory signaling pathway. The further investigations indicated that MMP8 was mainly expressed in myelocytes with a high degree of heterogeneity. MMP8-positive myelocytes interacted with other cell types through RETN-TLR4 and RETN-CAP1 ligand-receptor patterns. These findings emphasize the important role of MMP8 in COVID-19 progression and provide a potential therapeutic target for COVID-19 patients.

Musa paradisiaca L. Inflorescence Abrogates Neutrophil Activation by Downregulating TLR4/NF-KB Signaling Pathway in LPS-Induced Acute Lung Injury Model

Background/Objectives: Acute lung injury (ALI) is an inflammatory disorder affecting patients in intensive care with high mortality. No specific pharmacological treatment is available. Musa paradisiaca L. (banana) is a cosmopolitan plant, and homemade syrup from its inflorescence is used in many countries to treat pulmonary inflammation. Therefore, this study analyzed the hydroalcoholic extract (HEM) of the inflorescence on the ALI experimental model. Methods: Swiss mice were challenged with lipopolysaccharide and treated with HEM after 1, 24, and 48 h (five animals/group, three times). Results: The HEM-treated ALI mice presented a decrease in neutrophil migration in the bronchoalveolar lavage fluid (BALF), in the alveolar region, and in the blood, correlating to downregulation of CD18 expression. The HEM treatment also reduced the protein concentration in the BALF, caused lung edema formation, impaired NF-κB activation via inhibition of TLR4 signaling pathway, and decreased IL-1β, TNF-α production, free DNA release, and myeloperoxidase (MPO) activity. However, the extract induced an increased IL-10 in the BALF. Conclusions: Therefore, HEM's anti-inflammatory and immunomodulatory activities in ALI mice are by deactivating neutrophils by decreasing CD18 receptor, free DNA release, and MPO activity and inducing IL-10 production. Thus, this study supports the use of banana inflorescence in folk medicine and suggests its rational use to develop a phytomedicine to treat pulmonary inflammation.

Vitexin mitigates oxidative stress, mitochondrial damage, pyroptosis and regulates small nucleolar RNA host gene 1/DNA methyltransferase 1/microRNA-495 axis in sepsis-associated acute lung injury

AIM OF THE STUDY

This study examined vitexin's effect on sepsis-induced acute lung injury. We used network pharmacology and in vivo and in vitro experiments were performed to elucidate vitexin's role in preventing pyroptosis and regulating small nucleolar RNA host gene 1 (SNHG1)/DNA methyltransferase 1 (DNMT1)/microRNA-495 (miR-495 axis.

MATERIALS AND METHODS

We developed an acute lung injury model using C57BL/6 mice and MLE-12 cells. Through a combination of network pharmacology and in vitro screening, vitexin was identified as the most promising anti-inflammatory compound. Multiple techniques such as western blotting, real-time PCR, Hematoxylin and eosin staining, immunohistochemistry, and TUNEL assay were used. Additionally, immunofluorescence, DCFDA and TMRE staining, flow cytometry, methylation-specific PCR, and gene transfection techniques were performed to elucidate vitexin's potential targets and underlying mechanisms.

RESULTS

Vitexin treatment significantly reduced lung damage, neutrophil infiltration, and inflammation while improving tight junction integrity. In LPS-treated RAW264.7 macrophages and a septic mouse BALF-induced MLE-12 cell injury model, vitexin demonstrated anti-inflammatory effects, promoted M2 macrophage polarization, and enhanced regenerative markers. It also decreased oxidative stress, mitigated apoptosis and pyroptosis, and improved mitochondrial function. Our research uncovered a novel epigenetic regulatory mechanism involving lncRNA SNHG1, DNMT1, and miR-495.

CONCLUSION

Vitexin's ability to reduce inflammation, counteract oxidative stress, and modulate epigenetic processes. These findings underscore the promising role of vitexin as a treatment for ALI generated by sepsis. The SNHG1/miR-495 axis, which has been identified, represents a new target for future therapies in acute lung injury.

The impact of glucose metabolism on inflammatory processes in sepsis-induced acute lung injury

Acute lung injury (ALI) is a prevalent and critical complication of sepsis, marked by high incidence and mortality rates, with its pathogenesis still not being fully elucidated. Recent research has revealed a significant correlation between the metabolic reprogramming of glucose and sepsis-associated ALI (S-ALI). Throughout the course of S-ALI, immune cells, including macrophages and dendritic cells, undergo metabolic shifts to accommodate the intricate demands of immune function that emerge as sepsis advances. Indeed, glucose metabolic reprogramming in S-ALI serves as a double-edged sword, fueling inflammatory immune responses in the initial stages and subsequently initiating anti-inflammatory responses as the disease evolves. In this review, we delineate the current research progress concerning the pathogenic mechanisms linked to glucose metabolic reprogramming in S-ALI, with a focus on the pertinent immune cells implicated. We encapsulate the impact of glucose metabolic reprogramming on the onset, progression, and prognosis of S-ALI. Ultimately, by examining key regulatory factors within metabolic intermediates and enzymes, We have identified potential therapeutic targets linked to metabolic reprogramming, striving to tackle the inherent challenges in diagnosing and treating Severe Acute Lung Injury (S-ALI) with greater efficacy.

Restoring discarded porcine lungs by ex vivo removal of neutrophil extracellular traps

BACKGROUND

By causing inflammation and tissue damage, neutrophil extracellular traps (NETs) constitute an underlying mechanism of aspiration-induced lung injury, a major factor of the low utilization of donor lungs in lung transplantation (LTx).

METHODS

To determine whether NET removal during ex vivo lung perfusion (EVLP) can restore lung function and morphology in aspiration-damaged lungs, gastric aspiration lung injury was induced in 12 pigs. After confirmation of acute respiratory distress syndrome, the lungs were explanted and assigned to NET removal connected to EVLP (treated) (n = 6) or EVLP only (nontreated) (n = 6). Hemodynamic measurements were taken, and blood and tissue samples were collected to assess lung function, morphology, levels of cell-free DNA, extracellular histones, and nucleosomes as markers of NETs, as well as cytokine levels.

RESULTS

After EVLP and NET removal in porcine lungs, PaO2/FiO2 ratios increased significantly compared to those undergoing EVLP alone (p = 0.0411). Treated lungs had lower cell-free DNA (p = 0.0260) and lower levels of extracellular histones in EVLP perfusate (p= 0.0260) than nontreated lungs. According to histopathology, treated lungs showed less immune cell infiltration and less edema compared with nontreated lungs, which was reflected in decreased levels of proinflammatory cytokines in EVLP perfusate and bronchoalveolar lavage fluid.

CONCLUSIONS

To conclude, removing NETs during EVLP improved lung function and morphology in aspiration-damaged donor lungs. The ability to remove NETs during EVLP could represent a new therapeutic approach for LTx and potentially expand the donor pool for transplantation.

Targeted nuclear degranulation of neutrophils promotes the progression of pneumonia in ulcerative colitis

Background

Both intestinal and pulmonary systems are parts of the mucosal immune system, comprising ∼80% of all immune cells. These immune cells migrate or are transported between various mucosal tissues to maintain tissue homeostasis.

Methods

In this study, we isolated neutrophils from the peripheral blood of patients and utilized immunofluorescence, flow cytometry, and Western blotting to confirm the incidence of "nucleus-directed degranulation" in vitro. Subsequently, we conducted a precise analysis using arivis software. Furthermore, using the DSS mouse model of colitis and tissue clearing technologies, we validated the "targeted nuclear degranulation" of neutrophils and their migration to the lungs in an inflammatory intestinal environment.

Result

In this study, we found that among patients with ulcerative colitis, the migration of neutrophils with "targeted nuclear degranulation" from the intestinal mucosa to the lungs significantly exacerbates lung inflammation during pulmonary infections. Notably, patients with ulcerative colitis exhibited a higher abundance of neutrophils with targeted nuclear degranulation. Using DSS mice, we observed that neutrophils with targeted nuclear degranulation from the intestinal mucosa migrated to the lung and underwent activation during pulmonary infections. These neutrophils rapidly released a high amount of neutrophil extracellular traps to mediate the progression of lung inflammation. Alterations in the neutrophil cytoskeleton and its interaction with the nuclear membrane represent the primary mechanisms underlying targeted nuclear degranulation.

Conclusion

This study revealed that neutrophils accelerate lung inflammation progression in colitis, offering new insights and potential treatment targets for lung infections for patients with colitis.

Treating acute lung injury through scavenging of cell-free DNA by cationic nanoparticles

Acute lung injury (ALI) and acute respiratory distress syndrome are life-threatening conditions induced by inflammatory responses, in which cell-free DNA (cfDNA) plays a pivotal role. This study investigated the therapeutic potential of biodegradable cationic nanoparticles (cNPs) in alleviating ALI. Using a mouse model of lipopolysaccharide-induced ALI, we examined the impact of intravenously administered cNPs. Our findings indicate that cNPs possess robust DNA binding capability, enhanced accumulation in inflamed lungs, and a favorable safety profile in vivo. Furthermore, cNPs attenuate the inflammatory response in LPS-induced ALI mice by scavenging cfDNA, mainly derived from neutrophil extracellular traps, and activating the macrophage-mediated cGAS-STING pathway. The findings suggest a potential treatment for ALI by targeting cfDNA with cNPs. This approach has demonstrated efficacy in mitigating lung injury and merits further exploration.

Turning Neutrophil Cell Death Deadly in the Context of Hypertensive Vascular Disease

Hypertensive vascular disease (HVD) is a major health burden globally and is a comorbidity commonly associated with other metabolic diseases. Many factors are associated with HVD including obesity, diabetes, smoking, chronic kidney disease, and sterile inflammation. Increasing evidence points to neutrophils as an important component of the chronic inflammatory response in HVD. Neutrophils are abundant in the circulation and can respond rapidly upon stimulation to deploy an armament of antimicrobial effector functions. One of the outcomes of neutrophil activation is the generation of neutrophil extracellular traps (NETs), a regulated extrusion of chromatin and proteases. Although neutrophils and NETs are well described as components of the innate immune response to infection, recent evidence implicates them in HVD. Endothelial cell activation can trigger neutrophil adhesion, activation, and production of NETs promoting vascular dysfunction, vessel remodelling, and loss of resistance. The regulated release of NETs can be controlled by the pore-forming activities of distinct cell death pathways. The best characterized pathways in this context are apoptosis, pyroptosis, and necroptosis. In this review, we discuss how inflammatory cell death signalling and NET formation contribute to hypertensive disease. We also examine novel therapeutic approaches to limit NET production and their future potential as therapeutic drugs for cardiovascular disorders.

Plasma neutrophil extracellular traps in patients with sepsis-induced acute kidney injury serve as a new biomarker to predict 28-day survival outcomes of disease

Background

There is currently no accurate, readily available, or validated biomarker for assessing disease severity and survival outcomes in sepsis-induced acute kidney injury (SAKI), which limits the ability to conduct effective therapeutic interventions. The neutrophil extracellular traps (NETs) may be involved in the pathophysiology of SAKI. The present study investigated the predictive value of plasma NETs for the survival outcome of patients with SAKI.

Methods

This observational study included 136 SAKI patients, all of whom underwent a 28-day follow-up. According to the follow-up records, SAKI patients were divided into two groups: the non-survivor group (60 subjects) and the survivor group (76 subjects). Blood samples were collected after the diagnosis of AKI to measure three NET markers and 12 inflammatory indices. Correlation analysis, logistic regression analysis, receiver operating characteristic curve analysis, and survival analysis were performed.

Results

Compared to survivors, non-survivors among SAKI patients exhibited significantly higher levels of three plasma NET markers (all p < 0.001). Meanwhile, in SAKI patients, plasma levels of NET markers were significantly associated with serum levels of inflammatory indices. Additionally, serum interleukin (IL)-2, IL-8, IL-10, and tumor necrosis factor-alpha showed an interactive effect with plasma NET markers on the survival of SAKI patients. Furthermore, the combination of three plasma NET markers could identify SAKI patients with a poor 28-day survival with better accuracy (area under the curve = 0.857). Finally, plasma NET markers may independently predict the 28-day survival in SAKI patients.

Conclusion

Plasma NET markers were elevated in SAKI patients with poor outcomes and served as biomarkers for predicting 28-day survival in SAKI patients.

Risk signature of NETosis-related subtype predicts prognosis and evaluates immunotherapy effectiveness in gastric cancer

Background

Gastric cancer (GC) has a high incidence and mortality rate with a poor prognosis, so it is crucial to search for new biomarkers. The role of NETosis, a newly identified type of programmed cell death, in GC and its underlying mechanisms have yet to be explored and still require thorough investigation. Our research seeks to enhance our comprehension of NETosis and may offer novel approaches for treating GC.

Methods

Utilizing The Cancer Genome Atlas-stomach adenocarcinoma (TCGA-STAD) dataset for training and the GSE84433 dataset for validation, our study delved into the associations between NETosis-related genes and the clinical risk of GC. Through comprehensive clustering, enrichment, and immune infiltration analyses, we evaluated the prognostic relevance of these NETosis genes in vivo. Furthermore, we devised a NETosis-related risk signature (NRRS) to assess its implications in risk stratification, survival prognosis, immune infiltration, and drug sensitivity. The NRRS's accuracy was validated by immunohistochemical staining.

Results

By applying consensus clustering to data from 62 NETosis-related genes, we categorized patients into two distinct subgroups, C1 and C2. These subgroups demonstrated significant differences. Following this, we developed the NRRS using the least absolute shrinkage and selection operator (LASSO) regression analysis. This process involved the selection of the following genes: CXCR4, NRP1, PDCD1, CTLA4, AKR1B1, SERPINE1, RGS2, SLCO2A1, TNFAIP2, RNASE1, DOC2B, APOD, ENTPD2, and CCL24. High-risk and low-risk groups can be accurately distinguished. We further verify in the verification set. These results suggest that NETosis is related to the microenvironment of GC. Our designed NRRS can predict the survival of patients with GC.

Conclusions

We emphasized the relationship between NETosis and GC. We built and validated the value of NRRS. This contributes to deepening our view of NETosis and potentially provides new strategies for GC treatment.

Ameliorating lipopolysaccharide induced acute lung injury with Lianhua Qingke: focus on pulmonary endothelial barrier protection

Background

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) has long posed challenges in clinical practice, lacking established preventive and therapeutic approaches. Lianhua Qingke (LHQK), a patented traditional Chinese medicine (TCM), has been found to have anti-inflammatory effects for ameliorating ALI/ARDS induced by lipopolysaccharide (LPS). This study aimed to investigate the effects and potential mechanisms of LHQK on endothelial protection in LPS-induced ALI/ARDS in vivo and in LPS-induced human pulmonary microvascular endothelial cells (HPMECs) injury in vitro.

Methods

In the animal experiment, we induced an ALI/ARDS model by intratracheal injection of LPS (5 mg/mL). LHQK (3.7 g/kg/d for low dose and 7.4 g/kg/d for high dose) or dexamethasone (DEX) (5 mg/kg/d) was administered to mice 3 days prior to LPS treatment. In the in vitro experiments, HPMECs were pretreated with LHQK at concentrations of 125 and 250 µg/mL for 2 hours before being stimulated with LPS (10 µg/mL). We employed lung function test, measurement of lung index, hematoxylin and eosin (H&E) staining, bronchoalveolar lavage fluid (BALF) cell counts, and inflammatory cytokine levels to assess the therapeutic effect of LHQK. Additionally, the extravasation assay of fluorescein isothiocyanate-dextran (FITC-dextran) dye and the transmembrane electrical resistance (TEER) assay were used to evaluate endothelial barrier. Barrier integrity and relevant protein validation were assessed using immunofluorescence (IF) and Western blot analyses. Furthermore, network pharmacology analysis and cellular level screening were employed to predict and screen the active ingredients of LHQK.

Results

Compared to the LPS group, LHQK significantly improved lung function, mitigated lung pathological injuries, reduced inflammatory cells and inflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6] levels in BALF, and inhibited the expression of vascular cell adhesion molecule-1 (VCAM-1), attenuated LPS-induced pulmonary oedema and FITC-dextran permeability, and enhanced the expression of vascular endothelial-cadherin (VE-cadherin) and occludin. In vitro, LHQK attenuated LPS-induced HPMECs injury by elevating TEER values and enhancing VE-cadherin and occludin protein levels. Finally, network pharmacology analysis and cellular level validation identified potential active ingredients of LHQK.

Conclusions

In summary, LHQK can mitigate LPS-induced inflammatory infiltration, pulmonary edema, and pulmonary vascular endothelial barrier dysfunction in the context of ALI/ARDS. This is achieved by decreasing the levels of VCAM-1, and increasing the expression levels of barrier-associated junctions, such as VE-cadherin and occludin. Consequently, LHQK exhibits promising therapeutic potential in preventing the progression of ALI/ARDS.

Intranasal administration of Clostridium butyricum and its derived extracellular vesicles alleviate LPS-induced acute lung injury

Acute lung injury (ALI) is associated with high morbidity and mortality rates. However, its clinical treatment is limited. Currently, the treatment of lung diseases by regulating the lung microbiota has become a research hotspot. In this study, we investigated the protective effects of the intranasal administration of Clostridium butyricum and its derived extracellular vesicles (EVs) against lipopolysaccharide (LPS)-induced ALI. The results demonstrated that compared with the LPS group, the pre-treatment group with C. butyricum and its EVs reduced the expression of pro-inflammatory cytokines and alleviated the symptoms in ALI mice by inhibiting the TLR4/MyD88 signaling pathway. Moreover, C. butyricum and its derived EVs inhibited the expression of apoptosis-related proteins and increased the expression of lung barrier proteins. Additionally, the intervention of C. butyricum changed the composition of the pulmonary microbiota. At the species level, LPS significantly increased the relative abundance of Acinetobacter johnsonii, while C. butyricum reversed this effect. In conclusion, these data demonstrate that intranasal administration of C. butyricum and its EVs can prevent LPS-induced ALI by reducing inflammation, inhibiting apoptosis, and improving lung barrier function. Additionally, C. butyricum regulated the pulmonary microbiota of mice to alleviate LPS-induced ALI.IMPORTANCEThe disorder of pulmonary microbiota plays an important role in the progression of acute lung injury (ALI). However, very few studies have been conducted to treat ALI by modulating pulmonary microbiota. In this study, the diversity and composition of pulmonary microbiota were altered in lipopolysaccharide (LPS)-induced ALI mice, but the ecological balance of the pulmonary microbiota was restored by intranasal administration of Clostridium butyricum. Moreover, the study reported the mechanism of C. butyricum and its derived extracellular vesicles for the treatment of LPS-induced ALI. These results reveal the importance of pulmonary microbiota in ALI disease. It provides a new approach for the treatment of ALI with new-generation probiotics.

Activation of the AMPK/Nrf2 pathway ameliorates LPS-induced acute lung injury by inhibiting oxidative stress and reducing inflammation

BACKGROUND

Numerous diseases-related acute lung injury (ALI) contributed to high mortality. Currently, the therapeutic effect of ALI was still poor. The detailed mechanism of ALI remained elusive and this study aimed to elucidate the mechanism of ALI.

METHOD

This study was performed to expose the molecular mechanisms of AMPK/Nrf2 pathway regulating oxidative stress in LPS-induced AMI mice. The mouse ALI model was established via intraperitoneal injection of LPS, then the lung tissue and blood samples were obtained, followed by injection with Dimethyl fumarate (DMF). Finally, Western blot, HE staining, injury score, lung wet/dry ratio, reactive oxygen species (ROS) and ELISA were used to elucidate the mechanism of AMPK/Nrf2 pathway in LPS -induced acute lung injury by mediating oxidative stress.

RESULTS

The lung tissue injury score was evaluated, showing higher scores in the model group compared to the AMPK activator and control groups. DCFH-DA indicated that LPS increased ROS production, while AMPK activator DMF reduced it, with the model group exhibiting higher ROS levels than the control and AMPK activator groups. The lung wet/dry ratio was also higher in the model group. Western blot analysis revealed LPS reduced AMPK and Nrf2 protein levels, but DMF reversed this effect. ELISA results showed elevated IL-6 and IL-1β levels in the model group compared to the AMPK activator and control groups.

CONCLUSION

CONCLUSION: Activating the AMPK/Nrf2 pathway can improve LPS-induced acute lung injury by down-regulation of the oxidative stress and corresponding inflammatory factor level.

The multi-herbal decoction SH003 alleviates LPS-induced acute lung injury by targeting inflammasome and extracellular traps in neutrophils

BACKGROUND

Acute lung injury (ALI) is a devastating condition caused by sepsis, pneumonia, trauma, and more recently, COVID-19. SH003, an herbal formula consisted of Astragalus membranaceus, Angelica gigas and Trichosanthes kirilowii, is known for its effects on cancer and immunoregulation.

HYPOTHESIS/PURPOSE

Previous studies show SH003 exerts a promising anti-inflammatory effect. This study investigates the effect of modified SH003 on ALI using in silico, in vivo, and in vitro models.

STUDY DESIGN AND METHODS

We performed in silico-based analysis of SH003 on ALI-related pathways. C57BL/6 mice were intraperitoneally subjected to lipopolysaccharide (LPS) to induce septic ALI, followed by oral administration of SH003 for 2 weeks. Dexamethasone was used as the positive control. Human peripheral blood-derived polymorphonuclear neutrophils (PMN) were used to investigate the effect and mechanisms of SH003 on neutrophil extracellular trap (NET) formation.

RESULTS

Network pharmacology analysis suggested SH003 regulates lung inflammation by modulating NET formation. SH003 significantly reduced mortality in sepsis in vivo by inhibiting local and systemic inflammation, likely via nuclear factor kappa B and mitogen-activated protein kinase pathways-mediated inflammasome suppression. SH003 also decreased NET-related markers in lung tissues and inhibited LPS- and phorbol myristate acetate-induced NET formation in PMN. Cytometry time-of-flight analysis confirmed regulation of NETosis-related pathways by SH003.

CONCLUSION

SH003 effectively inhibits excessive immune responses in the lung by suppressing inflammasome activation and NET formation. These findings suggest SH003 as a potential therapeutic agent for septic ALI.

Impact of acute stress disorder on surfactant protein D levels in acute lung injury

Many people sustain acute lung injuries in road traffic collisions, but few studies have dealt with such injuries in live models. This study aimed to explore the basic pathophysiological and inflammatory changes in adult rabbits following acute thoracic trauma. We randomly assigned 50 rabbits to control and injury groups. Rabbits in the injury group were subjected to right chest pressure (2600 g) using a Hopkinson bar. Measurements were taken in the control group and 0, 24, 48, and 72 h after injury in the injury group. Injury severity was evaluated in gross view; with haematoxylin and eosin (H&E) staining; and through the serum changes of tumor necrosis factor alpha (TNF-α), surfactant protein D (SP-D), and neutrophils. Secretion changes in SP-D in right lung injured tissues were estimated by western blotting and qPCR. Serum TNF-α levels increased rapidly immediately after injury, gradually recovering after 24, 48, and 72 h (p < 0.01). The percentage of neutrophils in the accompanying blood showed a consistent trend. Gross necropsy and H&E staining indicated different levels of bleeding, alveoli exudation, and inflammatory transformation after impact. ELISA depicted the same trend in circulation (F = 22.902, p < 0.01). Western blotting showed that SP-D protein levels in tissues decreased at 0 h and increased at 24, 48, and 72 h. We demonstrate the feasibility of a model of impact lung injury. Primary impact caused injury without external signs. Inflammation began immediately, and the lungs began recovering at 24, 48, and 72 h, as shown by increased SP-D levels in circulation and tissues.With complaints of ALI and inflammation, SP-D may be a potential biomarker after chest trauma.

Development of a dexamethasone-hyaluronic acid conjugate with selective targeting effect for acute lung injury therapy

Acute lung injury (ALI), a critical complication of COVID-19, is characterized by widespread inflammation and severe pulmonary damage, necessitating intensive care for those affected. Although glucocorticoids (GCs), such as dexamethasone (Dex), have been employed clinically to lower mortality, their nonspecific systemic distribution has led to significant side effects, limiting their use in ALI treatment. In this study, we explored the conjugation of Dex to hyaluronic acid (HA) to achieve targeted delivery to inflamed lung tissues. We achieved a conjugation efficiency exceeding 98 % using a cosolvent system, with subsequent ester bond cleavage releasing the active Dex, as verified by liquid chromatography. Biodistribution and cellular uptake studies indicated the potential of the HA conjugate for cluster of differentiation 44 (CD44)-mediated targeting and accumulation. In a lipopolysaccharide-induced ALI mouse model, intravenous (IV) HA-Dex administration showed superior anti-inflammatory effects compared to free Dex administration. Flow cytometry analysis suggested that the HA conjugate preferentially accumulated in lung macrophages, suggesting the possibility of reducing clinical Dex dosages through this targeted delivery approach.

Downregulation of Tumor Suppressor Gene LKB1 During Severe Primary Graft Dysfunction After Human Lung Transplantation: Implication for the Development of Chronic Lung Allograft Dysfunction

BACKGROUND

Severe primary graft dysfunction (PGD) after lung transplantation (LTx) is a significant risk factor for the development of bronchiolitis obliterans syndrome (BOS). Recent data from our group demonstrated that small extracellular vesicles (sEVs) isolated from the plasma of LTx recipients with BOS have reduced levels of tumor suppressor gene liver kinase B1 (LKB1) and promote epithelial-to-mesenchymal transition (EMT) and fibrosis. Here, we hypothesized that early inflammatory responses associated with severe PGD (PGD2/3) can downregulate LKB1 levels in sEVs, predisposing to the development of chronic lung allograft dysfunction (CLAD).

METHODS

sEVs were isolated from the plasma of human participants by Exosome Isolation Kit followed by 0.20-µm filtration and characterized by NanoSight and immunoblotting analysis. Lung self-antigens (K alpha 1 tubulin, Collagen V), LKB1, nuclear factor kappa B, and EMT markers in sEVs were compared by densitometry analysis between PGD2/3 and no-PGD participants. Neutrophil-derived factors and hypoxia/reperfusion effects on LKB1 levels and EMT were analyzed in vitro using quantitative real-time polymerase chain reaction and Western blotting.

RESULTS

LKB1 was significantly downregulated in PGD2/3 sEVs compared with no-PGD sEVs. Within PGD2/3 participants, lower post-LTx LKB1 was associated with CLAD development. Hypoxia/reperfusion downregulates LKB1 and is associated with markers of EMT in vitro. Finally, lower LKB1 levels in PGD2/3 are associated with increased markers of EMT.

CONCLUSIONS

Our results suggest that in post-LTx recipients with PGD2/3, downregulation of LKB1 protein levels in sEVs is associated with increased EMT markers and may result in the development of CLAD. Our results also suggest that ischemia/reperfusion injury during LTx may promote CLAD through the early downregulation of LKB1.

Diminazene aceturate inhibits the SARS-CoV-2 spike protein-induced inflammation involving leukocyte migration and DNA extracellular traps formation

AIMS

To investigate the SARS-CoV-2 Spike protein (Spk)-induced inflammatory response and its downmodulation by diminazene aceturate (DIZE).

MATERIALS AND METHODS

Through inducing Spk inflammation in murine models, leukocyte migration to the peritoneum, levels of myeloperoxidase (MPO), malondialdehyde (MDA), rolling and adhesion of mesenteric leukocytes, and vascular permeability were investigated. Extracellular DNA traps (DETs) induced by Spk and the production of IL-6 and TNF-α were analyzed using human neutrophils, monocytes, and macrophages. In silico assays assessed the molecular interaction between DIZE and molecules related to leukocyte migration and DETs induction.

KEY FINDINGS

Spk triggered acute inflammation, demonstrated by increasing leukocyte migration. Oxidative stress was evidenced by elevated levels of MPO and MDA in the peritoneal liquid. DIZE attenuated cell migration, rolling, and leukocyte adhesion, improved vascular barrier function, mitigated DETs, and reduced the production of Spk-induced pro-inflammatory cytokines. Computational studies supported our findings, showing the molecular interaction of DIZE with targets such as β2 integrin, PI3K, and PAD2 due to its intermolecular coupling.

SIGNIFICANCE

Our results outline a novel role of DIZE as a potential therapeutic agent for mitigating Spk-induced inflammation.

Protective Effect of a Isothiazolinone Derivative on Acute Lung Injury by Regulating PI3K-AKT Signaling Pathway

Acute lung injury (ALI) is a prevalent organ injury in sepsis, characterized by an inflammatory reactive disorder. Both the incidence and mortality rates of ALI have been steadily increasing. Isothiazolinone derivatives have displayed anti-inflammatory activity and have shown effectiveness in treating pneumonia. The objective of the study is to assess the effects and mechanisms of the isothiazolinone derivative 4-benzoyl-2-butyl-5-(ethylsulfinyl)isothiazol-3(2H)-one (C6) on sepsis-induced ALI.The analysis of biological function and signal pathway enrichment demonstrated that C6 primarily exhibited anti-inflammatory effects. Administration of different doses of C6 through intraperitoneal injection significantly improved the survival rate, body temperature, and body mass of mice with ALI induced by cecal ligation and puncture (CLP). Additionally, it mitigated lung tissue injury, pulmonary edema, lung permeability, inflammatory cell infiltration, apoptosis, and the expression of inflammatory cytokines. Network targeting analysis and experimental validation in mouse leukemia cells of monocyte macrophage (RAW264.7) cells and CLP-induced ALI mice revealed that the anti-inflammatory effect of C6 was mediated by the inhibition of the phosphatidylinositol 3 kinase -protein kinase B (PI3K-AKT) signaling pathway. The research suggest that C6 has protective effects against ALI by inhibiting the PI3K-AKT signaling pathway. This information could be valuable in developing potential treatments for ALI.

Nanoparticle targeting of neutrophil glycolysis prevents lung ischemia-reperfusion injury

Neutrophils exacerbate pulmonary ischemia-reperfusion injury (IRI) resulting in poor short and long-term outcomes for lung transplant recipients. Glycolysis powers neutrophil activation, but it remains unclear if neutrophil-specific targeting of this pathway will inhibit IRI. Lipid nanoparticles containing the glycolysis flux inhibitor 2-deoxyglucose (2-DG) were conjugated to neutrophil-specific Ly6G antibodies (NP-Ly6G[2-DG]). Intravenously administered NP-Ly6G(2-DG) to mice exhibited high specificity for circulating neutrophils. NP-Ly6G(2-DG)-treated neutrophils were unable to adapt to hypoglycemic conditions of the lung airspace environment as evident by the loss of demand-induced glycolysis, reductions in glycogen and ATP content, and an increased vulnerability to apoptosis. NP-Ly6G(2-DG) treatment inhibited pulmonary IRI following hilar occlusion and orthotopic lung transplantation. IRI protection was associated with less airspace neutrophil extracellular trap generation, reduced intragraft neutrophilia, and enhanced alveolar macrophage efferocytotic clearance of neutrophils. Collectively, our data show that pharmacologically targeting glycolysis in neutrophils inhibits their activation and survival leading to reduced pulmonary IRI.

Role of biomarkers and molecular signaling pathways in acute lung injury

BACKGROUND

Acute lung injury (ALI) is caused by bacterial, fungal, and viral infections. When pathogens invade the lungs, the immune system responds by producing cytokines, chemokines, and interferons to promote the infiltration of phagocytic cells, which are essential for pathogen clearance. Their excess production causes an overactive immune response and a pathological hyper-inflammatory state, which leads to ALI. Until now, there is no particular pharmaceutical treatment available for ALI despite known inflammatory mediators like neutrophil extracellular traps (NETs) and reactive oxygen species (ROS).

OBJECTIVES

Therefore, the primary objective of this review is to provide the clear overview on the mechanisms controlling NETs, ROS formation, and other relevant processes during the pathogenesis of ALI. In addition, we have discussed the significance of epithelial and endothelial damage indicators and several molecular signaling pathways associated with ALI.

METHODS

The literature review was done from Web of Science, Scopus, PubMed, and Google Scholar for ALI, NETs, ROS, inflammation, biomarkers, Toll- and nucleotide-binding oligomerization domain (NOD)-like receptors, alveolar damage, pro-inflammatory cytokines, and epithelial/endothelial damage alone or in combination.

RESULTS

This review summarized the main clinical signs of ALI, including the regulation and distinct function of epithelial and endothelial biomarkers, NETs, ROS, and pattern recognition receptors (PRRs).

CONCLUSION

However, no particular drugs including vaccine for ALI has been established. Furthermore, there is a lack of validated diagnostic tools and a poor predictive rationality of current therapeutic biomarkers. Hence, extensive and precise research is required to speed up the process of drug testing and development by the application of artificial intelligence technologies, structure-based drug design, in-silico approaches, and drug repurposing.

Using the sympathetic system, beta blockers and alpha-2 agonists, to address acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) manifests as an acute inflammatory lung injury characterized by persistent hypoxemia, featuring a swift onset, high mortality, and predominantly supportive care as the current therapeutic approach, while effective treatments remain an area of active investigation. Adrenergic receptors (AR) play a pivotal role as stress hormone receptors, extensively participating in various inflammatory processes by initiating downstream signaling pathways. Advancements in molecular biology and pharmacology continually unveil the physiological significance of distinct AR subtypes. Interventions targeting these subtypes have the potential to induce specific alterations in cellular and organismal functions, presenting a promising avenue as a therapeutic target for managing ARDS. This article elucidates the pathogenesis of ARDS and the basic structure and function of AR. It also explores the relationship between AR and ARDS from the perspective of different AR subtypes, aiming to provide new insights for the improvement of ARDS.

Adipose-Derived exosome from Diet-Induced-Obese mouse attenuates LPS-Induced acute lung injury by inhibiting inflammation and Apoptosis: In vivo and in silico insight

BACKGROUND

Acute lung injury (ALI) is a severe clinical condition in the intensive care units, and obesity is a high risk of ALI. Paradoxically, obese ALI patients had better prognosis than non-obese patients, and the mechanism remains largely unknown.

METHODS

Mouse models of ALI and diet-induced-obesity (DIO) were used to investigate the effect of exosomes derived from adipose tissue. The adipose-derived exosomes (ADEs) were isolated by ultracentrifugation, and the role of exosomal miRNAs in the ALI was studied.

RESULTS

Compared with ADEs of control mice (C-Exo), ADEs of DIO mice (D-Exo) increased survival rate and mitigated pulmonary lesions of ALI mice. GO and KEGG analyses showed that the target genes of 40 differentially expressed miRNAs between D-Exo and C-Exo were mainly involved with inflammation, apoptosis and cell cycle. Furthermore, the D-Exo treatment significantly decreased Ly6G+ cell infiltration, down-regulated levels of pro-inflammatory cytokines (IL-6, IL-12, TNF-α, MCP-1) and chemokines (IL-8 and MIP-2), reduced pulmonary apoptosis and arrest at G0G1 phase (P < 0.01). And the protective effects of D-Exo were better than those of C-Exo (P < 0.05). Compared with the C-Exo mice, the levels of miR-16-5p and miR-335-3p in the D-Exo mice were significantly up-regulated (P < 0.05), and the expressions of IKBKB and TNFSF10, respective target of miR-16-5p and miR-335-3p by bioinformatic analysis, were significantly down-regulated in the D-Exo mice (P < 0.05).

CONCLUSIONS

Exosomes derived from adipose tissue of DIO mice are potent to attenuate LPS-induced ALI, which could be contributed by exosome-carried miRNAs. Our data shed light on the interaction between obesity and ALI.

Experimental Insights on the Use of Secukinumab and Magnolol in Acute Respiratory Diseases in Mice

This study investigates the combined treatment of secukinumab (SECU) and magnolol (MAGN) in a mouse model of LPS-induced ALI overlapped with allergic pulmonary inflammation, aiming to better understand the mechanism behind this pathology and to assess the therapeutic potential of this novel approach in addressing the severity of ALI. The combined treatment reveals intricate immunomodulatory effects. Both treatments inhibit IL-17 and promote M2 macrophage polarization, which enhances anti-inflammatory cytokine production such as IL-4, IL-5, IL-10, and IL-13, crucial for lung repair and inflammation resolution. However, the combination treatment exacerbates allergic responses and increases OVA-specific IgE, potentially worsening ALI outcomes. MAGN pretreatment alone demonstrates higher potency in reducing neutrophils and enhancing IFN-γ, suggesting its potential in mitigating severe asthma symptoms and modulating immune responses. The study highlights the need for careful consideration in therapeutic applications due to the combination treatment's inability to reduce IL-6 and its potential to exacerbate allergic inflammation. Elevated IL-6 levels correlate with worsened oxygenation and increased mortality in ALI patients, underscoring its critical role in disease severity. These findings offer valuable insights for the advancement of precision medicine within the realm of respiratory illnesses, emphasizing the importance of tailored therapeutic strategies.

Advances in nanomaterial-targeted treatment of acute lung injury after burns

Acute lung injury (ALI) is a common complication in patients with severe burns and has a complex pathogenesis and high morbidity and mortality rates. A variety of drugs have been identified in the clinic for the treatment of ALI, but they have toxic side effects caused by easy degradation in the body and distribution throughout the body. In recent years, as the understanding of the mechanism underlying ALI has improved, scholars have developed a variety of new nanomaterials that can be safely and effectively targeted for the treatment of ALI. Most of these methods involve nanomaterials such as lipids, organic polymers, peptides, extracellular vesicles or cell membranes, inorganic nanoparticles and other nanomaterials, which are targeted to reach lung tissues to perform their functions through active targeting or passive targeting, a process that involves a variety of cells or organelles. In this review, first, the mechanisms and pathophysiological features of ALI occurrence after burn injury are reviewed, potential therapeutic targets for ALI are summarized, existing nanomaterials for the targeted treatment of ALI are classified, and possible problems and challenges of nanomaterials in the targeted treatment of ALI are discussed to provide a reference for the development of nanomaterials for the targeted treatment of ALI.

Pathophysiological changes and injury markers for acute lung injury from blunt impact in infant rabbits

Background

Traffic accidents, particularly blunt impacts, cause serious injuries in children. We aimed to assess inflammatory and injury responses in infant rabbits subjected to acute lung injury resulting from blunt impact, with the goal of identifying potential circulatory injury markers.

Methods

Forty 4-week-old infant rabbits were subjected to a right chest impact using a Hopkinson bar with 2,600 g. Computed tomography was employed to assess injury severity. Pathological changes were observed using hematoxylin and eosin staining in the control, 0, 24, and 72 h groups, post-injury. Immunohistochemistry was used to examine surfactant protein A (SP-A) changes in right lung tissues and upper main bronchi. Serum levels of interleukin-6 (IL-6), IL-8, and SP-A were measured using ELISA within 24 h post-injury in the control, 0 h, and 24 h groups.

Results

Following blunt injury, significant increases were observed in blood white blood cell count (F = 101.556, P < 0.01) and neutrophil percentage (F = 104.228, P < 0.01), which gradually decreased after 24 and 72 h. The lung wet/dry weight ratio indicated significant edema (F = 79.677, P < 0.01), corroborated by hematoxylin and eosin staining showing edema, exudation, and marked granulocyte infiltration in the control, 0 h, 24 h and 72 h groups. SP-A levels decreased rapidly at 0 h, and recovered between 24 and 72 h in the right lung tissues (F = 6.7, P < 0.05), left lung (F = 15.825, P < 0.05) and upper main bronchi (F = 59.552, P < 0.01). The ELISA results showed increasing trends for the control and 0 h groups, while decreasing trends were observed in 24 h group for IL-6 (F = 58.328, P < 0.01) and IL-8 (F = 41.802, P < 0.01). Conversely, SP-A exhibited a decreasing trend in the control and 0 h groups but increased in the serum of 24 h group (F = 52.629, P < 0.01).

Discussion

In cases of direct chest trauma in infant rabbits, particularly mild injuries without rib fractures. SP-A levels correlated with pathological changes across all groups and may serve as biomarkers for pediatric blunt lung impact.

A Rapid In Vivo Toxicity Assessment Method for Antimicrobial Peptides

Antimicrobial peptides (AMPs) represent a promising antibiotic alternative to overcome drug-resistant bacteria by inserting into the membrane of bacteria, resulting in cell lysis. However, therapeutic applications of AMPs have been hindered by their ability to lyse eukaryotic cells. GF-17 is a truncated peptide of LL-37, which has perfect amphipathicity and a higher hydrophobicity, resulting in higher haemolytic activity. However, there is no significant difference in the cytotoxicity against human lung epithelial cells between the GF-17 and LL-37 groups, indicating that there are significant differences in the sensitivity of different human cells to GF-17. In this study, LL-37 and GF-17 were administered to mouse lungs via intranasal inoculation. Blood routine examination results showed that LL-37 did not affect the red blood cells, platelet, white blood cells and neutrophil counts, but GF-17 decreased the white blood cells and neutrophil counts with the increasing concentration of peptides. GF-17-treated mice suffer a body weight loss of about 2.3 g on average in 24 h, indicating that GF-17 is highly toxic to mice. The total cell counts in the bronchoalveolar lavage fluid from GF-17-treated mice were 4.66-fold that in the untreated group, suggesting that GF-17 treatment leads to inflammation in the lungs of mice. Similarly, the histological results showed the infiltration of neutrophils in the lungs of GF-17-treated mice. The results suggest that the administration of GF-17 in the lungs of mice does not affect the red blood cells and platelet counts in the blood but promotes neutrophil infiltration in the lungs, leading to an inflammatory response. Therefore, we established a mouse acute lung injury model to preliminarily evaluate the in vivo toxicity of AMPs. For AMPs with a clinical application value, systematic research is still needed to evaluate their acute and long-term toxicity.

Neutrophil extracellular traps linked to idiopathic pulmonary fibrosis severity and survival

Background

Idiopathic pulmonary fibrosis (IPF) leads to progressive loss of lung function and mortality. Understanding mechanisms and markers of lung injury in IPF is paramount to improving outcomes for these patients. Despite the lack of systemic involvement in IPF, many analyses focus on identifying circulating prognostic markers. Using a proteomic discovery method followed by ELISA validation in multiple IPF lung compartments and cohorts we explored novel markers of IPF survival.

Methods

In our discovery analysis, agnostic label-free quantitative proteomics differentiated lung tissue protein expression based on survival trajectory (n=10). Following selection of the candidate pathway (neutrophil extracellular trap (NET) formation), we subsequently validated the presence of NETs in the IPF lung microenvironment using fully quantitative assays of known NET remnants in separate IPF cohorts (n=156 and n=52) with bronchoalveolar lavage fluid. We then assessed the correlation of these markers with baseline pulmonary function and survival.

Results

Discovery lung tissue proteomics identified NET formation as significantly associated with poor IPF survival. Using fully quantitative confirmatory tests for reproducibility we confirmed the presence of NET markers in IPF BALF and found significant correlations with worse pulmonary function in both cohorts (p<0.03 and p = 0.04 respectively). In the survival cohort, higher levels of NET markers predicted worse survival after adjusting for gender, age, and baseline physiologic severity (hazard ratio range: 1.79-2.19).

Conclusions

NET markers were associated with disease severity and worse survival in IPF. These findings suggest NET formation contributes to lung injury and decreased survival in IPF and may represent a potential therapeutic target.

Endothelial cell dynamics in sepsis-induced acute lung injury and acute respiratory distress syndrome: pathogenesis and therapeutic implications

Sepsis, a prevalent critical condition in clinics, continues to be the leading cause of death from infections and a global healthcare issue. Among the organs susceptible to the harmful effects of sepsis, the lungs are notably the most frequently affected. Consequently, patients with sepsis are predisposed to developing acute lung injury (ALI), and in severe cases, acute respiratory distress syndrome (ARDS). Nevertheless, the precise mechanisms associated with the onset of ALI/ARDS remain elusive. In recent years, there has been a growing emphasis on the role of endothelial cells (ECs), a cell type integral to lung barrier function, and their interactions with various stromal cells in sepsis-induced ALI/ARDS. In this comprehensive review, we summarize the involvement of endothelial cells and their intricate interplay with immune cells and stromal cells, including pulmonary epithelial cells and fibroblasts, in the pathogenesis of sepsis-induced ALI/ARDS, with particular emphasis placed on discussing the several pivotal pathways implicated in this process. Furthermore, we discuss the potential therapeutic interventions for modulating the functions of endothelial cells, their interactions with immune cells and stromal cells, and relevant pathways associated with ALI/ARDS to present a potential therapeutic strategy for managing sepsis and sepsis-induced ALI/ARDS.

[Neutrophil extracellular traps extrusion from neutrophils stably adhered to ICAM-1 by lipoteichoic acid stimulation]

The effect of neutrophil extracellular traps (NETs) on promoting intravascular microthrombi formation and exacerbating the severity of sepsis in patients has gained extensive attention. However, in sepsis, the mechanisms and key signaling molecules mediating NET formation during direct interactions of endothelial cells and neutrophils still need further explored. Herein, we utilized lipoteichoic acid (LTA), a component shared by Gram-positive bacteria, to induce NET extrusion from neutrophils firmly adhered to the glass slides coated with intercellular adhesion molecule-1(ICAM-1). We also used Sytox green to label NET-DNA and Flou-4 AM as the intracellular Ca 2+ signaling indicator to observe the NET formation and fluctuation of Ca 2+ signaling. Our results illustrated that LTA was able to induce NET release from neutrophils firmly attached to ICAM-1-coated glass slides, and the process was time-dependent. In addition, our study indicated that LTA-induced NET release by neutrophils stably adhered to ICAM-1 depended on Ca 2+ signaling but not intracellular reactive oxygen species (ROS). This study reveals NET formation mediated by direct interactions between endothelial ICAM-1 and neutrophils under LTA stimulation and key signaling molecules involved, providing the theoretical basis for medicine development and clinical treatment for related diseases.

Neutrophil Extracellular Traps and Respiratory Disease

Extracellular traps made by neutrophils (NETs) and other leukocytes such as macrophages and eosinophils have a key role in the initial immune response to infection but are highly inflammatory and may contribute to tissue damage. They are particularly relevant to lung disease, with the pulmonary anatomy facilitating their ability to fully extend into the airways/alveolar space. There has been a rapid expansion in the number of published studies demonstrating their role in a variety of important respiratory diseases including chronic obstructive pulmonary disease, cystic fibrosis, bronchiectasis, asthma, pneumonia, COVID-19, rhinosinusitis, interstitial lung disease and lung cancer. The expression of NETs and other traps is a specific process, and diagnostic tests need to differentiate them from other inflammatory pathways/causes of cell death that are also characterised by the presence of extracellular DNA. The specific targeting of this pathway by relevant therapeutics may have significant clinical benefit; however, current clinical trials/evidence are at a very early stage. This review will provide a broad overview of the role of NETs and their possible treatment in respiratory disease.

Corilagin Inhibits Neutrophil Extracellular Trap Formation and Protects against Hydrochloric Acid/Lipopolysaccharide-Induced Acute Lung Injury in Mice by Suppressing the STAT3 and NOX2 Signaling Pathways

Acute lung injury (ALI) and its severe manifestation, acute respiratory distress syndrome (ARDS), are characterized by uncontrolled inflammatory responses, neutrophil activation and infiltration, damage to the alveolar capillary membrane, and diffuse alveolar injury. Neutrophil extracellular traps (NETs), formed by activated neutrophils, contribute significantly to various inflammatory disorders and can lead to tissue damage and organ dysfunction. Corilagin, a compound found in Phyllanthus urinaria, possesses antioxidative and anti-inflammatory properties. In this study, we investigated the protective effects and underlying mechanisms of corilagin in hydrochloric acid (HCl)/lipopolysaccharide (LPS)-induced lung injury. Mice received intraperitoneal administration of corilagin (2.5, 5, or 10 mg/kg) or an equal volume of saline 30 min after intratracheal HCl/LPS administration. After 20 h, lung tissues were collected for analysis. Corilagin treatment significantly mitigated lung injury, as evidenced by reduced inflammatory cell infiltration, decreased production of proinflammatory cytokines, and alleviated oxidative stress. Furthermore, corilagin treatment suppressed neutrophil elastase expression, reduced NET formation, and inhibited the expression of ERK, p38, AKT, STAT3, and NOX2. Our findings suggest that corilagin inhibits NET formation and protects against HCl/LPS-induced ALI in mice by modulating the STAT3 and NOX2 signaling pathways.

Role of the Skin Immune System in Wound Healing

Wound healing is a dynamic and complex process, characterized by the coordinated activities of multiple cell types, each with distinct roles in the stages of hemostasis, inflammation, proliferation, and remodeling. The cells of the immune system not only act as sentinels to monitor the skin and promote homeostasis, but they also play an important role in the process of skin wound repair. Skin-resident and recruited immune cells release cytokines and growth factors that promote the amplification of the inflammatory process. They also work with non-immune cells to remove invading pathogens and debris, as well as guide the regeneration of damaged host tissues. Dysregulation of the immune system at any stage of the process may lead to a prolongation of the inflammatory phase and the development of a pathological condition, such as a chronic wound. The present review aims to summarize the roles of different immune cells, with special emphasis on the different stages of the wound healing process.

Nanoparticles for stimulation of neutrophil extracellular trap-mediated immunity

Neutrophil extracellular traps (NETs) have been identified as triggers for a self-limited inflammatory reaction upon contact with nanoparticles within our bodies. This typically results in entrapping potentially harmful nano- or micro-objects following an immune burst. The demand for potent adjuvants has led to research on particulate-based adjuvants, particularly those that act via NET formation. Various particles, including hydrophobic nanoparticles, needle-like microparticles, and other natural and artificial crystals, have been shown to induce NET formation, eliciting a robust humoral and cellular immune response toward co-injected antigens. The NET formation was found to be the basis of the efficient use of alum as a vaccine adjuvant. Thus, nanoparticles with specific surface properties serve as NET-stimulating adjuvants. In this mini-review, we aim to summarize the current knowledge about the surface properties of particulate objects and the molecular pathways involved in inducing NET formation by neutrophils. Additionally, we discuss the potential use of nanoparticles for activating neutrophils in the tissues and the exploitation of such activation for enhancing vaccine adjuvants.

The impact and relevance of techniques and fluids on lung injury in machine perfusion of lungs

Primary graft dysfunction (PGD) is a common complication after lung transplantation. A plethora of contributing factors are known and assessment of donor lung function prior to organ retrieval is mandatory for determination of lung quality. Specialized centers increasingly perform ex vivo lung perfusion (EVLP) to further assess lung functionality and improve and extend lung preservation with the aim to increase lung utilization. EVLP can be performed following different protocols. The impact of the individual EVLP parameters on PGD development, organ function and postoperative outcome remains to be fully investigated. The variables relate to the engineering and function of the respective perfusion devices, such as the type of pump used, functional, like ventilation modes or physiological (e.g. perfusion solutions). This review reflects on the individual technical and fluid components relevant to EVLP and their respective impact on inflammatory response and outcome. We discuss key components of EVLP protocols and options for further improvement of EVLP in regard to PGD. This review offers an overview of available options for centers establishing an EVLP program and for researchers looking for ways to adapt existing protocols.

Advances in lung ischemia/reperfusion injury: unraveling the role of innate immunity

BACKGROUND

Lung ischemia/reperfusion injury (LIRI) is a common occurrence in clinical practice and represents a significant complication following pulmonary transplantation and various diseases. At the core of pulmonary ischemia/reperfusion injury lies sterile inflammation, where the innate immune response plays a pivotal role. This review aims to investigate recent advancements in comprehending the role of innate immunity in LIRI.

METHODS

A computer-based online search was performed using the PubMed database and Web of Science database for published articles concerning lung ischemia/reperfusion injury, cell death, damage-associated molecular pattern molecules (DAMPs), innate immune cells, innate immunity, inflammation.

RESULTS

During the process of lung ischemia/reperfusion, cellular injury even death can occur. When cells are injured or undergo cell death, endogenous ligands known as DAMPs are released. These molecules can be recognized and bound by pattern recognition receptors (PRRs), leading to the recruitment and activation of innate immune cells. Subsequently, a cascade of inflammatory responses is triggered, ultimately exacerbating pulmonary injury. These steps are complex and interrelated rather than being in a linear relationship. In recent years, significant progress has been made in understanding the immunological mechanisms of LIRI, involving novel types of cell death, the ability of receptors other than PRRs to recognize DAMPs, and a more detailed mechanism of action of innate immune cells in ischemia/reperfusion injury (IRI), laying the groundwork for the development of novel diagnostic and therapeutic approaches.

CONCLUSIONS

Various immune components of the innate immune system play critical roles in lung injury after ischemia/reperfusion. Preventing cell death and the release of DAMPs, interrupting DAMPs receptor interactions, disrupting intracellular inflammatory signaling pathways, and minimizing immune cell recruitment are essential for lung protection in LIRI.

Ferritin-mediated neutrophil extracellular traps formation and cytokine storm via macrophage scavenger receptor in sepsis-associated lung injury

BACKGROUND

Sepsis is a severe systemic inflammatory disorder manifested by a dysregulated immune response to infection and multi-organ failure. Numerous studies have shown that elevated ferritin levels exist as an essential feature during sepsis and are able to suggest patients' prognoses. At the same time, the specific mechanism of ferritin-induced inflammatory injury remains unclear.

METHODS

Hyper-ferritin state during inflammation was performed by injecting ferritin into a mouse model and demonstrated that injection of ferritin could induce a systemic inflammatory response and increase neutrophil extracellular trap (NET) formation.Padi4-/-, Elane-/- and Cybb-/- mice were used for the NETs formation experiment. Western blot, immunofluorescence, ELISA, and flow cytometry examined the changes in NETs, inflammation, and related signaling pathways.

RESULTS

Ferritin induces NET formation in a peptidylarginine deiminase 4 (PAD4), neutrophil elastase (NE), and reactive oxygen species (ROS)-dependent manner, thereby exacerbating the inflammatory response. Mechanistically, ferritin induces the expression of neutrophil macrophage scavenger receptor (MSR), which promotes the formation of NETs. Clinically, high levels of ferritin in patients with severe sepsis correlate with NETs-mediated cytokines storm and are proportional to the severity of sepsis-induced lung injury.

CONCLUSIONS

In conclusion, we demonstrated that hyper-ferritin can induce systemic inflammation and increase NET formation in an MSR-dependent manner. This process relies on PAD4, NE, and ROS, further aggravating acute lung injury. In the clinic, high serum ferritin levels are associated with elevated NETs and worse lung injury, which suggests a poor prognosis for patients with sepsis. Our study indicated that targeting NETs or MSR could be a potential treatment to alleviate lung damage and systemic inflammation during sepsis. Video Abstract.

Mesenchymal stem cells alleviate sepsis-induced acute lung injury by blocking neutrophil extracellular traps formation and inhibiting ferroptosis in rats

Acute lung injury (ALI) is one of the most serious complications of sepsis, characterized by high morbidity and mortality rates. Ferroptosis has recently been reported to play an essential role in sepsis-induced ALI. Excessive neutrophil extracellular traps (NETs) formation induces exacerbated inflammation and is crucial to the development of ALI. In this study, we explored the effects of ferroptosis and NETs and observed the therapeutic function of mesenchymal stem cells (MSCs) on sepsis-induced ALI. First, we produced a cecal ligation and puncture (CLP) model of sepsis in rats. Ferrostain-1 and DNase-1 were used to inhibit ferroptosis and NETs formation separately, to confirm their effects on sepsis-induced ALI. Next, U0126 was applied to suppress the MEK/ERK signaling pathway, which is considered to be vital to NETs formation. Finally, the therapeutic effect of MSCs was observed on CLP models. The results demonstrated that both ferrostain-1 and DNase-1 application could improve sepsis-induced ALI. DNase-1 inhibited ferroptosis significantly in lung tissues, showing that ferroptosis could be regulated by NETs formation. With the inhibition of the MEK/ERK signaling pathway by U0126, NETs formation and ferroptosis in lung tissues were both reduced, and sepsis-induced ALI was improved. MSCs also had a similar protective effect against sepsis-induced ALI, not only inhibiting MEK/ERK signaling pathway-mediated NETs formation, but also alleviating ferroptosis in lung tissues. We concluded that MSCs could protect against sepsis-induced ALI by suppressing NETs formation and ferroptosis in lung tissues. In this study, we found that NETs formation and ferroptosis were both potential therapeutic targets for the treatment of sepsis-induced ALI, and provided new evidence supporting the clinical application of MSCs in sepsis-induced ALI treatment.

A Narrative Review: The Role of NETs in Acute Respiratory Distress Syndrome/Acute Lung Injury

Nowadays, acute respiratory distress syndrome (ARDS) still has a high mortality rate, and the alleviation and treatment of ARDS remains a major research focus. There are various causes of ARDS, among which pneumonia and non-pulmonary sepsis are the most common. Trauma and blood transfusion can also cause ARDS. In ARDS, the aggregation and infiltration of neutrophils in the lungs have a great influence on the development of the disease. Neutrophils regulate inflammatory responses through various pathways, and the release of neutrophils through neutrophil extracellular traps (NETs) is considered to be one of the most important mechanisms. NETs are mainly composed of DNA, histones, and granuloproteins, all of which can mediate downstream signaling pathways that can activate inflammatory responses, generate immune clots, and cause damage to surrounding tissues. At the same time, the components of NETs can also promote the formation and release of NETs, thus forming a vicious cycle that continuously aggravates the progression of the disease. NETs are also associated with cytokine storms and immune balance. Since DNA is the main component of NETs, DNase I is considered a viable drug for removing NETs. Other therapeutic methods to inhibit the formation of NETs are also worthy of further exploration. This review discusses the formation and mechanism of NETs in ARDS. Understanding the association between NETs and ARDS may help to develop new perspectives on the treatment of ARDS.

B cells mediate lung ischemia/reperfusion injury by recruiting classical monocytes via synergistic B cell receptor/TLR4 signaling

Ischemia/reperfusion injury-mediated (IRI-mediated) primary graft dysfunction (PGD) adversely affects both short- and long-term outcomes after lung transplantation, a procedure that remains the only treatment option for patients suffering from end-stage respiratory failure. While B cells are known to regulate adaptive immune responses, their role in lung IRI is not well understood. Here, we demonstrated by intravital imaging that B cells are rapidly recruited to injured lungs, where they extravasate into the parenchyma. Using hilar clamping and transplant models, we observed that lung-infiltrating B cells produce the monocyte chemokine CCL7 in a TLR4-TRIF-dependent fashion, a critical step contributing to classical monocyte (CM) recruitment and subsequent neutrophil extravasation, resulting in worse lung function. We found that synergistic BCR-TLR4 activation on B cells is required for the recruitment of CMs to the injured lung. Finally, we corroborated our findings in reperfused human lungs, in which we observed a correlation between B cell infiltration and CM recruitment after transplantation. This study describes a role for B cells as critical orchestrators of lung IRI. As B cells can be depleted with currently available agents, our study provides a rationale for clinical trials investigating B cell-targeting therapies.

Neutrophil extracellular traps and their implications in airway inflammatory diseases

Neutrophil extracellular traps (NETs) are essential for immune defense and have been increasingly recognized for their role in infection and inflammation. In the context of airway inflammatory diseases, there is growing evidence suggesting the involvement and significance of NETs. This review aims to provide an overview of the formation mechanisms and components of NETs and their impact on various airway inflammatory diseases, including acute lung injury/ARDS, asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. By understanding the role of NETs in airway inflammation, we can gain valuable insights into the underlying pathogenesis of these diseases and identify potential targets for future therapeutic strategies that either target NETs formation or modulate their harmful effects. Further research is warranted to elucidate the complex interactions between NETs and airway inflammation and to develop targeted therapies that can effectively mitigate their detrimental effects while preserving their beneficial functions in host defense.