Hemostatic imbalance in dogs with sepsis is characterized by hypercoagulability and hypofibrinolysis. We aimed to determine whether these abnormalities are unique features of sepsis or are also present in dogs with non-septic critical illness. Secondary aims were to assess relationships between coagulation assay results and circulating markers of neutrophil extracellular traps (NETs), and to relate coagulation assay abnormalities with survival in dogs with sepsis.

This prospective single-center observational cohort study enrolled 55 client-owned dogs that satisfied at least 2 systemic inflammatory response syndrome (SIRS) criteria. Dogs with a bacterial infection were categorized as sepsis, those without evidence of infection were categorized as non-infectious systemic inflammation (nSIRS). Clotting times, fibrinogen and D-dimer concentrations, and activities of antithrombin (AT), antiplasmin (AP), thrombin activatable fibrinolysis inhibitor (TAFI), and total and active plasminogen activator inhibitor-1 (PAI-1) were measured. Thrombin generation and overall hemostasis potential assays were performed and concentrations of cell-free DNA (cfDNA) and H3.1 nucleosomes quantitated.

Compared to dogs with nSIRS, dogs with sepsis had higher fibrinogen concentrations, greater endogenous thrombin potential, higher AP and TAFI activities and greater overall hemostasis and coagulation potential values. H3.1 nucleosome and cfDNA concentrations were strongly correlated and significantly associated with various coagulation variables. In dogs with sepsis, non-survivors had lower AT activity, and higher active PAI-1 and H3.1 nucleosome concentrations.

Relative to non-septic critically ill dogs, dogs with sepsis are hyperfibrinogenemic, hypercoagulable and have higher AP and TAFI activities. Concentrations of H3.1 nucleosomes and active PAI-1 and AT activity might have prognostic value in dogs with sepsis.

Acute respiratory distress syndrome (ARDS) is a life-threatening condition characterized by severe hypoxemia and high mortality. Ferroptosis, a form of regulated cell death driven by iron accumulation and lipid peroxidation, has emerged as a critical mechanism in ARDS pathogenesis. However, the molecular regulators of ferroptosis in ARDS remain unclear. This study integrates multi-omics analysis and experimental validation to identify ferroptosis-related targets in ARDS. Bronchoalveolar lavage fluid (BALF) samples from ARDS patients and healthy controls were subjected to proteomics and metabolomics analysis. Transcriptomic data from the GSE243066 dataset and ferroptosis-related gene databases were integrated to identify key genes. Functional enrichment analyses were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. An LPS-induced ARDS mouse model was established for experimental validation, including Western blotting, histopathology, and ferroptosis-related biochemical assays. Multi-omics analysis identified YWHAE as a ferroptosis-associated gene significantly upregulated in ARDS. Functional enrichment revealed key pathways, including ferroptosis, hypoxia-inducible factor-1 signaling, and oxidative stress responses. Proteomic and transcriptomic integration highlighted 51 overlapping differentially expressed genes, with YWHAE emerging as a central hub in the protein-protein interaction network. Metabolomics analysis further revealed glutathione and cysteine metabolism as critical pathways linked to ferroptosis. In the ARDS mouse model, ferroptosis inhibitor ferrostatin-1 (Fer-1) attenuated LPS-induced lung injury, reduced oxidative stress markers, and downregulated YWHAE expression. This study identifies YWHAE as a novel ferroptosis-related target in ARDS through multi-omics analysis and experimental validation. These findings provide new insights into the molecular mechanisms of ferroptosis in ARDS and highlight YWHAE as a potential therapeutic target for future interventions.

Selenoproteins (Sels) are a class of essential biomolecules that play critical roles in cellular homeostasis. SelO was identified as the preferential source of selenium in the liver, implying its potential as a key regulatory factor in hepatic pathophysiology. Bioinformatics analysis of data from GEO data sets revealed marked downregulation of SelO in liver injury. However, its function and regulatory mechanisms in the liver remain unclear. To address this, we investigated the effect of SelO ablation on acute liver inflammation, focusing on its association with inflammation and neutrophil extracellular traps (NETs) formation. Wild-type (WT) and SelO-knockout mice were used to establish a lipopolysaccharide (LPS) exposure model and a coculture model (AML12 cells and neutrophils) in vitro. Our findings revealed that LPS stimulation significantly reduced SelO expression in the WT mouse liver. SelO deletion promoted the expression of Hmgb1 and marker cytokines for chemokines, NETs generation, pyroptosis and inflammation, and induced an imbalance in redox homeostasis. Immunofluorescence, SYTOX staining, and scanning electron microscopy confirmed that SelO silencing promoted reactive oxygen species (ROS)-dependent NETs formation. Moreover, the coculture model demonstrated that excessive NETs formation exacerbated SelO-ablation-induced hepatic inflammation. Importantly, we confirmed the significant involvement of the Hmgb1/ROS axis in the development of acute liver inflammation in the absence of SelO. Our results demonstrated that SelO ablation promoted neutrophil recruitment and enhanced ROS-dependent NETs formation by increasing Hmgb1 expression levels, thereby aggravating LPS-induced pyroptosis and inflammation. This study not only uncovered the crucial biological functions of SelO, but also shed light on its regulatory implications in the inflammatory process.

Acute lung injury (ALI) induced by lipopolysaccharide (LPS) is a significant medical condition characterized by severe pulmonary inflammation and tissue damage. NLRP3 inflammasome-driven inflammation is essential in ALI pathogenesis, inspiring novel therapeutic strategies that focus on NLRP3 and inflammation. In this study, we investigated the therapeutic potential of 5-deoxy-rutaecarpine (5-DR), a rutaecarpine derivative, in attenuating LPS-induced ALI.

In this study, we evaluated the effects of 5-DR treatment in mice exposed to LPS, lung tissues, bronchoalveolar lavage fluid, and serum were collected for analysis. LPS-stimulated J774A.1 mouse macrophages were used to further investigate the anti-inflammatory effects of 5-DR in vitro. Various techniques including histopathology, Western blotting, and luciferase reporter assay were employed.

5-DR treatment significantly reduced lung edema, inflammatory cell infiltration in mice with LPS burden, and reduced the levels of inflammatory mediators like interleukin-1β in the mice and in LPS-stimulated J774A.1 mouse macrophages. Further western blotting analysis showed 5-DR decreased the levels of NLRP3, cleaved caspase-1, and mature IL-1β in mice and J774A.1 cells exposed to LPS. Additionally, NF-κB pathway activation significantly diminished the inhibition of the NLRP3 inflammasome by 5-DR.

Our findings highlight the therapeutic potential of 5-DR as a promising candidate for treating LPS-induced ALI, offering insights into its underlying mechanism that targets NLRP3 inflammasome-mediated inflammation.

The Gram-negative bacterium Klebsiella pneumoniae (K. pneumoniae) is one major causative agent of community- and hospital-acquired pneumonia. Echinacoside (ECH) is a phenylethanoid glycoside isolated from Cistanche deserticola that possesses anti-inflammatory activity. Our research aimed to confirm whether ECH alleviates K. pneumoniae-induced pneumonia and explore the underlying regulatory mechanisms. BEAS-2B cells and BALB/c mice were infected by K. pneumoniae to establish the cellular and animal models, respectively, followed by ECH treatment. Inflammatory cytokine levels were detected by RT-qPCR and ELISA. The lung wet/dry (W/D) weight ratio and the myeloperoxidase (MPO) activity in lung tissues were examined. The pulmonary histopathologic changes were observed through hematoxylin and eosin (H&E) staining. The levels of TLR4/NF-κB pathway-associated molecules were estimated through western blotting, immunohistochemical, and immunohistochemical staining. K. pneumoniae infection caused lung histopathologic damage, enhanced MPO activity, elevated lung W/D weight ratio, and upregulated inflammatory cytokine levels in mice and promoted inflammatory cytokine expression in BEAS-2B cells, which were reversed by ECH treatment. K. pneumoniae infection-induced upregulation in TLR4, phosphorylated (p)-p65, and p-IκBα levels, and downregulation in IκBα levels in BEAS-2B cells and pneumonia mice were overturned by ECH treatment. ECH ameliorates K. pneumoniae-induced pneumonia through suppressing the TLR4/NF-κB pathway.

Evidence shows that diabetes raises the probability of contracting COVID-19 and associated complications. We hypothesize that metformin, being pleiotropic, may improve COVID-19 in diabetics.

A retrospective cohort study was conducted with 421 COVID-19 patients with diabetes, hospitalized between 1st April 2020 and 31st March 2022 in a tertiary-care hospital. Patients with metformin or its combination constituted the study cohort (SC; n = 221), while other antidiabetics constituted the reference cohort (RC; n = 200).

SC and RC were matched for mean age ± SD (SC: 53.3 ± 5.7 vs. RC: 54.3 ± 8.2 years). The mean length of hospitalization (days) was significantly shorter in SC (9.0 ± 5.7) than in RC (12.7 ± 6) (p < 0.02). Metformin use was associated with reduction in mortality risk (OR: 0.106, 95% CI = 0.039-0.287; p < 0.001). Moreover, SC also improved levels of LDH (OR: 0.243, 95% CI = 0.104-0.566; p < 0.001), CRP (OR: 0.281, 95% CI = 0.120-0.659; p < 0.004), and D-dimer (OR: 0.220, 95% CI = 0.089-0.539; p < 0.001) than RC. The calculated number needed to treat for metformin was 3.1.

Metformin users have a decrease in hospital stay and mortality rates and improvement in LDH, CRP, and D-dimer levels. Therefore, metformin might protect against mortality in COVID-19 with diabetes.

Although the role of low-density granulocytes (LDGs), neutrophils in the peripheral blood mononuclear cell (PBMC) fraction, and neutrophil extracellular traps (NETs) in assessing lupus disease severity is acknowledged, data specific to childhood-onset lupus remains scarce. This study analyzed 46 patients with childhood-onset systemic lupus erythematosus (82.6% females, mean age 14.5 ± 0.3 years), including 26 cases with normal complement levels and 20 with low complement levels, along with 20 healthy adult volunteers. Key parameters that distinguished healthy volunteers from lupus patients and differentiated between lupus patients with low and normal complement were serum interferon (IFN)-α, serum citrullinated histone 3 (CitH3), and extracellular traps (ETs) in LDGs. However, NETs (assessed by nuclear staining morphology), LDG abundance, and other parameters (such as endotoxemia, cytokines, and double-stranded (ds) DNA) did not show such differentiation. When lipopolysaccharide (LPS) was administered to LDGs in the PBMC fraction, it induced ETs in both low and normal complement groups, indicating the inducible nature of ETs. In adult healthy volunteers, activation by recombinant IFN-α or dsDNA in isolated neutrophils induced LDGs and NETs (identified using immunofluorescent staining for CitH3, myeloperoxidase, and neutrophil elastase) at 45 min and 3 h post-stimulation, respectively. Additionally, approximately half of the LDGs underwent late apoptosis at 3 h post-stimulation, as determined by flow cytometry analysis. Activation by IFN-α or dsDNA in LDGs also led to a more pronounced expression of CD66b, an adhesion molecule, compared to regular-density neutrophils, suggesting higher activity in LDGs. In conclusion, IFN-α and/or dsDNA in serum may transform regular-density neutrophils into LDGs before progressing to NETosis and apoptosis, potentially exacerbating lupus severity through cell death-induced self-antigens. Therefore, LDGs and ETs in LDGs could provide deeper insights into the pathophysiology of childhood-onset lupus.

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.

Modulating SYK has been demonstrated to have impacts on pathogenic neutrophil responses in COVID-19. During sepsis, neutrophils are vital in early bacterial clearance but also contribute to the dysregulated immune response and organ injury when hyperactivated. Here, we evaluated the impact of R406, the active metabolite of fostamatinib, on neutrophils stimulated by LPS. We demonstrate that R406 was able to effectively inhibit NETosis, degranulation, ROS generation, neutrophil adhesion, and the formation of CD16low neutrophils that have been linked to detrimental outcomes in severe sepsis. Further, the neutrophils remain metabolically active, capable of releasing cytokines, perform phagocytosis, and migrate in response to IL-8. Taken together, this data provides evidence of the potential efficacy of utilizing fostamatinib in bacterial sepsis.

The pathogenesis of acute lung injury is complex. Studies have demonstrated the role of neutrophil extracellular traps (NETs) in the process of lipopolysaccharide (LPS)-induced acute lung injury (ALI). However, the underlying mechanism remains unclear. In this study, the regulation of Nrf2 in the formation of NETs, which was pathogenic in LPS-induced ALI, was identified by analyzing the levels of Cit-H3, lung function, lung tissue pathology, lung wet/dry ratio, the inflammatory cells, cytokines and proteins in the bronchoalveolar lavage fluid (BALF) and in addition, the activity of lung myeloperoxidase (MPO) was also measured. Results showed that the levels of Cit-H3 measured by western blot in Nrf2-knockout (KO) mice were higher compared with the WT mice after LPS stimulation. To further investigate the NETs formation was pathogenic during LPS-induced ALI, the Nrf2-KO mice were treated with DNase I. Results showed that DNase I improved lung function and lung tissue pathology and significantly reduced lung wet/dry ratio and proteins in the BALF. Besides, DNase I also attenuated the infiltration of inflammatory cells and the cytokines (TNF-α, IL-1β) production in the BALF and the activity of lung MPO. Therefore, these results together indicate that Nrf2 may intervene in the release of NETs during LPS-induced ALI in mice.

The chemokine CCL28 is highly expressed in mucosal tissues, but its role during infection is not well understood. Here, we show that CCL28 promotes neutrophil accumulation in the gut of mice infected with Salmonella and in the lung of mice infected with Acinetobacter. Neutrophils isolated from the infected mucosa expressed the CCL28 receptors CCR3 and, to a lesser extent, CCR10, on their surface. The functional consequences of CCL28 deficiency varied between the two infections: Ccl28-/- mice were highly susceptible to Salmonella gut infection but highly resistant to otherwise lethal Acinetobacter lung infection. In vitro, unstimulated neutrophils harbored pre-formed intracellular CCR3 that was rapidly mobilized to the cell surface following phagocytosis or inflammatory stimuli. Moreover, CCL28 stimulation enhanced neutrophil antimicrobial activity, production of reactive oxygen species, and formation of extracellular traps, all processes largely dependent on CCR3. Consistent with the different outcomes in the two infection models, neutrophil stimulation with CCL28 boosted the killing of Salmonella but not Acinetobacter. CCL28 thus plays a critical role in the immune response to mucosal pathogens by increasing neutrophil accumulation and activation, which can enhance pathogen clearance but also exacerbate disease depending on the mucosal site and the infectious agent.

Pneumocystis jirovecii pneumonia (PjP) poses a serious risk to individuals with compromised immune systems, such as individuals with HIV/AIDS or undergoing immunosuppressive therapies for cancer or solid organ transplants. Severe PjP triggers excessive lung inflammation, resulting in lung function decline and consequential alveolar damage, potentially culminating in acute respiratory distress syndrome. Non-HIV patients face a 30%-60% mortality rate, emphasizing the need for a deeper understanding of inflammatory responses in PjP. Prior research emphasized macrophages in Pneumocystis infections, neglecting neutrophils' role in tissue damage. Consequently, the overemphasis on macrophages led to an incomplete understanding of the role of neutrophils and inflammatory responses. In the current investigation, our RNAseq studies on a murine surrogate model of PjP revealed heightened activation of the NLRP3 inflammasome and NETosis cell death pathways in their lungs. Immunofluorescence staining confirmed neutrophil extracellular trap (NET) presence in the lungs of the P. murina-infected mice, validating our findings. Moreover, isolated neutrophils exhibited NETosis when directly stimulated with P. murina. Isolated NETs compromised P. murina viability in vitro, highlighting the potential role of neutrophils in controlling fungal growth and promoting inflammation during P. murina pneumonia through NLRP3 inflammasome assembly and NETosis. These pathways, essential for inflammation and pathogen elimination, bear the risk of uncontrolled activation leading to excessive tissue damage and persistent inflammation. This pioneering study is the first to identify the formation of NETs and inflammasomes during Pneumocystis infection, paving the way for comprehensive investigations into treatments aimed at mitigating lung damage and augmenting survival rates for individuals with PjP.IMPORTANCEPneumocystis jirovecii pneumonia (PjP) affects individuals with weakened immunity, such as HIV/AIDS, cancer, and organ transplant patients. Severe PjP triggers lung inflammation, impairing function and potentially causing acute respiratory distress syndrome. Non-HIV individuals face a 30%-60% mortality rate, underscoring the need for deeper insight into PjP's inflammatory responses. Past research focused on macrophages in managing Pneumocystis infection and its inflammation, while the role of neutrophils was generally overlooked. In contrast, our findings in P. murina-infected mouse lungs showed neutrophil involvement during inflammation and increased expression of NLRP3 inflammasome and NETosis pathways. Detection of neutrophil extracellular traps further indicated their involvement in the inflammatory process. Although beneficial in combating infection, unregulated neutrophil activation poses a potential threat to lung tissues. Understanding the behavior of neutrophils in Pneumocystis infections is crucial for controlling detrimental reactions and formulating treatments to reduce lung damage, ultimately improving the survival rates of individuals with PjP.

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).

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.

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.

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).

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.

Neutrophilic inflammation, characterized by dysregulated neutrophil activation, triggers a variety of inflammatory responses such as chemotactic infiltration, oxidative bursts, degranulation, neutrophil extracellular traps (NETs) formation, and delayed turnover. This type of inflammation is pivotal in the pathogenesis of acute respiratory distress syndrome (ARDS) and psoriasis. Despite current treatments, managing neutrophil-associated inflammatory symptoms remains a significant challenge.

This review emphasizes the role of cyclin-dependent kinases (CDKs) in neutrophil activation and inflammation. It aims to highlight the therapeutic potential of repurposing CDK inhibitors to manage neutrophilic inflammation, particularly in ARDS and psoriasis. Additionally, it discusses the necessary precautions for the clinical application of these inhibitors due to potential off-target effects and the need for dose optimization.

CDKs regulate key neutrophilic functions, including chemotactic responses, degranulation, NET formation, and apoptosis. Repurposing CDK inhibitors, originally developed for cancer treatment, shows promise in controlling neutrophilic inflammation. Clinical anticancer drugs, palbociclib and ribociclib, have demonstrated efficacy in treating neutrophilic ARDS and psoriasis by targeting off-label pathways, phosphoinositide 3-kinase (PI3K) and phosphodiesterase 4 (PDE4), respectively. While CDK inhibitors offer promising therapeutic benefits, their clinical repurposing requires careful consideration of off-target effects and dose optimization. Further exploration and clinical trials are necessary to ensure their safety and efficacy in treating inflammatory conditions.

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are life-threatening diseases. Neutrophil extracellular traps (NETs) play a key role in lung damage. Geranylgeranyl diphosphate synthase (GGPPS) is associated with the development of inflammatory diseases. We aimed to explore the role of GGPPS in NETs formation in ARDS/ALI. First, lung pathological changes in lipopolysaccharide (LPS)-induced ALI mice after myeloid-specific GGPPS deletion were evaluated. The level of NETs formation was analyzed by immunofluorescence, PicoGreen assay and Western blotting. Next, we determined the role of GGPPS in NETs formation and underlying mechanisms using immunofluorescence, flow cytometry, DCFH-DA, and SYTOX GREEN staining in vitro. Finally, the correlation between GGPPS expression incirculating neutrophils and dsDNA levels in plasma was evaluated. Myeloid-specific GGPPS deletion mice showed increased NETs deposition in lung tissue and aggravated histopathological damage of lung tissue. In vitro, GGPPS deficiency in neutrophils resulted in increased NETs formation by Phorbol-12-myristate-13-acetate (PMA), which was reversed by Geranylgeranyl diphosphate (GGPP). In addition, inhibitors blocking protein kinase C (PKC) and NADPH-oxidase (NOX) decreased NETs formation induced by GGPPS deletion. Importantly, GGPPS expression in circulating neutrophils was decreased in ARDS patients compared with the healthy control, and the level of dsDNA in plasma of ARDS patients was negatively correlated with the GGPPS expression. Taken together, GGPPS deficiency in neutrophils aggravates LPS-induced lung injury by promoting NETs formation via PKC/NOX signaling. Thus, neutrophil GGPPS could be a key therapeutic target for ARDS.

Acute lung injury (ALI) manifests through harm to the capillary endothelium and alveolar epithelial cells, arising from a multitude of factors, leading to scattered interstitial alterations, pulmonary edema, and subsequent acute hypoxic respiratory insufficiency. Acute lung injury (ALI), along with its more serious counterpart, acute respiratory distress syndrome (ARDS), carry a fatality rate that hovers around 30-40%. Its principal pathological characteristic lies in the unchecked inflammatory reaction. Currently, the main strategies for treating ALI are alleviation of inflammation and prevention of respiratory failure. Concerning the etiology of ALI, NLRP3 Inflammasome is essential to the body's innate immune response. The composition of this inflammasome complex includes NLRP3, the pyroptosis mediator ASC, and pro-caspase-1. Recent research has reported that the inflammatory response centered on NLRP3 inflammasomes plays a key part in inflammation in ALI, and may hence be a prospective candidate for therapeutic intervention. In the review, we present an overview of the ailment characteristics of acute lung injury along with the constitution and operation of the NLRP3 inflammasome within this framework. We also explore therapeutic strategies targeting the NLRP3 inflammasome to combat acute lung injury.

Acute lung injury (ALI) is a life-threatening lung disease characterized by inflammatory cell infiltration and lung epithelial injury. Icariside II (ICS II), one of the main active ingredients of Herba Epimedii, exhibits anti-inflammatory and immunomodulatory effects. However, the effect and mechanism of ICS II in ALI remain unclear. The purpose of the current study was to investigate the pharmacological effect and underlying mechanism of ICS II in ALI.

Models of neutrophil-like cells, human peripheral blood neutrophils, and lipopolysaccharide (LPS)-induced ALI mouse model were utilized. RT-qPCR and Western blotting determined the gene and protein expression levels. Protein distribution and quantification were analyzed by immunofluorescence.

ICS II significantly reduced lung histopathological damage, edema, and inflammatory cell infiltration, and it reduced pro-inflammatory cytokines in ALI. There is an excessive activation of neutrophils leading to a significant production of NETs in ALI mice, a process mitigated by the administration of ICS II. In vivo and in vitro studies found that ICS II could decrease NET formation by targeting neutrophil C-X-C chemokine receptor type 4 (CXCR4). Further data showed that ICS II reduces the overproduction of dsDNA, a NETs-related component, thereby suppressing cGAS/STING/NF-κB signalling pathway activation and inflammatory mediators release in lung epithelial cells.

This study suggested that ICS II may alleviate LPS-induced ALI by modulating the inflammatory response, indicating its potential as a therapeutic agent for ALI treatment.

The gut microbiota and short chain fatty acids (SCFA) have been associated with immune regulation and autoimmune diseases. Autoimmune kidney diseases arise from a loss of tolerance to antigens, often with unclear triggers. In this review, we explore the role of the gut microbiome and how disease, diet, and therapy can alter the gut microbiota consortium. Perturbations in the gut microbiota may systemically induce the translocation of microbiota-derived inflammatory molecules such as liposaccharide (LPS) and other toxins by penetrating the gut epithelial barrier. Once in the blood stream, these pro-inflammatory mediators activate immune cells, which release pro-inflammatory molecules, many of which are antigens in autoimmune diseases. The ratio of gut bacteria Bacteroidetes/Firmicutes is associated with worse outcomes in multiple autoimmune kidney diseases including lupus nephritis, MPO-ANCA vasculitis, and Goodpasture's syndrome. Therapies that enhance SCFA-producing bacteria in the gut have powerful therapeutic potential. Dietary fiber is fermented by gut bacteria which in turn release SCFAs that protect the gut barrier, as well as modulating immune responses towards a tolerogenic anti-inflammatory state. Herein, we describe where the current field of research is and the strategies to harness the gut microbiome as potential therapy.

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.

Neutrophil extracellular traps (NETs) play a role in innate pathogen defense and also trigger B-cell response by providing antigens. NETs have been linked to vaccine-induced thrombotic thrombocytopenia. We postulated a potential link between NET biomarkers, NET-promoting autoantibodies, and adverse events (AEs) after COVID-19 vaccine boosters. Healthy donors (HDs) who received ChAdOx1-S (A), mRNA-1273 (M), or recombinant protein (MVC-COV1901) vaccines at the National Taiwan University Hospital between 2021 and 2022 were recruited. We measured serial NET-associated biomarkers, citrullinated-histone3 (citH3), and myeloperoxidase (MPO)-DNA. Serum citH3 and MPO-DNA were significantly or numerically higher in HDs who reported AEs (n = 100, booster Day 0/Day 30, p = 0.01/p = 0.03 and p = 0.30/p = 0.35, respectively). We also observed a positive correlation between rash occurrence in online diaries and elevated citH3. A linear mixed model also revealed significantly higher citH3 levels in mRNA-1273/ChAdOx1-S recipients than MVC-COV1901 recipients. Significant positive correlations were observed between the ratios of anti-heparin platelet factor 4 and citH3 levels on Booster Day 0 and naïve and between the ratios of anti-NET IgM and citH3 on Booster Day 30/Day 0 in the AA-M and MM-M group, respectively. The increased levels of citH3/MPO-DNA accompanied by NET-promoting autoantibodies suggest a potential connection between mRNA-1273/ChAdOx1-S vaccines and cardiovascular complications. These findings provide insights for risk assessments of future vaccines.

Excessive release of neutrophil extracellular traps (NETs) has been reported in various human pathologies, including COVID-19 patients. Elevated NET levels serve as a biomarker, indicating increased coagulopathy and immunothrombosis risks in these patients. Traditional immunoassays employed to quantify NET release focus on bulk measurements of released chromatin in simplified microenvironments. In this study, we fabricated a novel NET-array device to quantify NET release from primary human neutrophils with single-cell resolution in the presence of the motile bacteria Pseudomonas aeruginosa PAO1 and inflammatory mediators. The device was engineered to have wide chambers and constricted loops to measure NET release in variably confined spaces. Our open NET-array device enabled immunofluorescent labeling of citrullinated histone H3, a NET release marker. We took time-lapse images of primary healthy human neutrophils releasing NETs in clinically relevant infection and inflammation-rich microenvironments. We then developed a computer-vision-based image processing method to automate the quantification of individual NETs. We showed a significant increase in NET release to Pseudomonas aeruginosa PAO1 when challenged with inflammatory mediators tumor necrosis factor-α [20 ng mL-1] and interleukin-6 [50 ng mL-1], but not leukotriene B4 [20 nM], compared to the infection alone. We also quantified the temporal dynamics of NET release and differences in the relative areas of NETs, showing a high percentage of variable size NET release with combined PAO1 - inflammatory mediator treatment, in the device chambers. Importantly, we demonstrated reduced NET release in the confined loops of our combined infection-inflammation microsystem. Ultimately, our NET-array device stands as a valuable tool, facilitating experiments that enhance our comprehension of the spatiotemporal dynamics of NET release in response to infection within a defined microenvironment. In the future, our system can be used for high throughput and cost-effective screening of novel immunotherapies on human neutrophils in view of the importance of fine-tuning NET release in controlling pathological neutrophil-driven inflammation.

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.

Acute respiratory distress syndrome (ARDS) is a life-threatening event that occurs in patients suffering from bacterial, fungal, or viral sepsis. Research performed over the last five decades showed that ARDS is a consequence of severe unrestrained systemic inflammation, which leads to injury of the lung's microvasculature and alveolar epithelium. ARDS leads to acute hypoxic/hypercapnic respiratory failure and death in a significant number of patients hospitalized in intensive care units worldwide. Basic and clinical research performed during the time since ARDS was first described has been unable to construct a pharmacological agent that will combat the inflammatory fire leading to ARDS. In-depth studies of the molecular pharmacology of vitamin C indicate that it can serve as a potent anti-inflammatory agent capable of attenuating the pathobiological events that lead to acute injury of the lungs and other body organs. This analysis of vitamin C's role in the treatment of ARDS includes a focused systematic review of the literature relevant to the molecular physiology of vitamin C and to the past performance of clinical trials using the agent.

Acute respiratory distress syndrome (ARDS) is an acute diffuse inflammatory lung injury characterized by the damage of alveolar epithelial cells and pulmonary capillary endothelial cells. It is mainly manifested by non-cardiogenic pulmonary edema, resulting from intrapulmonary and extrapulmonary risk factors. ARDS is often accompanied by immune system disturbance, both locally in the lungs and systemically. As a common heterogeneous disease in critical care medicine, researchers are often faced with the failure of clinical trials. Latent class analysis had been used to compensate for poor outcomes and found that targeted treatment after subgrouping contribute to ARDS therapy. The subphenotype of ARDS caused by sepsis has garnered attention due to its refractory nature and detrimental consequences. Sepsis stands as the most predominant extrapulmonary cause of ARDS, accounting for approximately 32% of ARDS cases. Studies indicate that sepsis-induced ARDS tends to be more severe than ARDS caused by other factors, leading to poorer prognosis and higher mortality rate. This comprehensive review delves into the immunological mechanisms of sepsis-ARDS, the heterogeneity of ARDS and existing research on targeted treatments, aiming to providing mechanism understanding and exploring ideas for accurate treatment of ARDS or sepsis-ARDS.

Wound healing is an extremely complex process involving multiple levels of cells and tissues. It is mainly completed through four stages: haemostasis, inflammation, proliferation, and remodelling. When any one of these stages is impaired, it may lead to delayed healing or even transformation into chronic refractory wounds. Diabetes is a kind of common metabolic disease that affects approximately 500 million people worldwide, 25% of whom develop skin ulcers that break down repeatedly and are difficult to heal, making it a growing public health problem. Neutrophils extracellular traps and ferroptosis are new types of programmed cell death identified in recent years and have been found to interact with diabetic wounds. In this paper, the normal wound healing and interfering factors of the diabetic refractory wound were outlined. The mechanism of two kinds of programmed cell death was also described, and the interaction mechanism between different types of programmed cell death and diabetic refractory wounds was discussed.

Acute respiratory distress syndrome (ARDS) is a critical form of acute lung injury (ALI). Here, we investigated the effect of a defined combination of ten pure phytochemicals in equal proportions of weight (NPM) from plants, recommended by Ayurveda for any protective action against lipopolysaccharide (LPS)-induced ALI. Results indicate that NPM markedly improved protein and neutrophil contents, myeloperoxidase and hydroxyproline levels, oxidative stress markers (glutathione and malonaldehyde), inflammatory cytokines, and genes (IL-6, TNF-α, TGF-β, and NF-κB/IκBα) in BALF/lung tissue. The histopathological examination of the lung revealed the shielding effect of NPM against ALI. NPM exhibited a protective effect on the lung by reducing oxidative stress and inhibiting inflammation. A substantial drop in favipiravir's oral exposure was observed in ALI-state compared to normal-state, but oral exposure upon NPM treatment in ALI-state followed similar behaviour of favipiravir alike normal-state without NPM treatment. Overall, results offer potential insight into Ayurvedic recommendations for immunity boosting during ALI situations.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are associated with high morbidity and mortality. Excessive neutrophil infiltration into the pulmonary airspace is the main cause for the acute inflammation and lung injury. Platelets have been implicated in the pathogenesis of ALI/ARDS, but the underlying mechanisms are not fully understood. Here, we show that the immunoreceptor tyrosine-based activation motif-coupled immunoglobulin-like platelet receptor, glycoprotein VI (GPVI), plays a key role in the early phase of pulmonary thrombo-inflammation in a model of lipopolysaccharide (LPS)-induced ALI in mice. In wild-type (WT) control mice, intranasal LPS application triggered severe pulmonary and blood neutrophilia, hypothermia, and increased blood lactate levels. In contrast, GPVI-deficient mice as well as anti-GPVI-treated WT mice were markedly protected from pulmonary and systemic compromises and showed no increased pulmonary bleeding. High-resolution multicolor microscopy of lung sections and intravital confocal microcopy of the ventilated lung revealed that anti-GPVI treatment resulted in less stable platelet interactions with neutrophils and overall reduced platelet-neutrophil complex (PNC) formation. Anti-GPVI treatment also reduced neutrophil crawling and adhesion on endothelial cells, resulting in reduced neutrophil transmigration and alveolar infiltrates. Remarkably, neutrophil activation was also diminished in anti-GPVI-treated animals, associated with strongly reduced formation of PNC clusters and neutrophil extracellular traps (NETs) compared with that in control mice. These results establish GPVI as a key mediator of neutrophil recruitment, PNC formation, and NET formation (ie, NETosis) in experimental ALI. Thus, GPVI inhibition might be a promising strategy to reduce the acute pulmonary inflammation that causes ALI/ARDS.

LHQK is a patented Traditional Chinese Medicine (TCM) which is clinically used for acute tracheobronchitis, cough, and other respiratory diseases. Recent studies have proved that LHQK exhibits excellent clinical efficacy in the treatment of acute lung injury (ALI). However, the corresponding mechanisms remain largely unexplored. In this study, we investigated the effects and the underlying mechanisms of LHQK on lipopolysaccharide (LPS)-induced ALI in mice. The pathological examination, inflammatory cytokines assessments, and mucus secretion evaluation indicated that administration of LHQK ameliorated LPS-induced lung injury, and suppressed the secretion of Muc5AC and pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β) in plasma and BALF. Furthermore, the results of cell-free DNA level showed that LHQK significantly inhibited LPS-induced NETs formation. Western blot revealed that LHQK effectively inhibited LPS-triggered pyroptosis in the lung. In addition, RNA-Seq data analysis, relatively bioinformatic analysis, and network pharmacology analysis revealed that LHQK and relative components may play multiple protective functions in LPS-induced ALI/acute respiratory distress syndrome (ARDS) by regulating multiple targets directly or indirectly related to NETs and pyroptosis. In conclusion, LHQK can effectively attenuate lung injury and reduce lung inflammation by inhibiting LPS-induced NETs formation and pyroptosis, which may be regulated directly or indirectly by active compounds of LHQK.

Post-acute COVID-19 sequelae, commonly known as long COVID, encompasses a range of systemic symptoms experienced by a significant number of COVID-19 survivors. The underlying pathophysiology of long COVID has become a topic of intense research discussion. While chronic inflammation in long COVID has received considerable attention, the role of neutrophils, which are the most abundant of all immune cells and primary responders to inflammation, has been unfortunately overlooked, perhaps due to their short lifespan. In this review, we discuss the emerging role of neutrophil extracellular traps (NETs) in the persistent inflammatory response observed in long COVID patients. We present early evidence linking the persistence of NETs to pulmonary fibrosis, cardiovascular abnormalities, and neurological dysfunction in long COVID. Several uncertainties require investigation in future studies. These include the mechanisms by which SARS-CoV-2 brings about sustained neutrophil activation phenotypes after infection resolution; whether the heterogeneity of neutrophils seen in acute SARS-CoV-2 infection persists into the chronic phase; whether the presence of autoantibodies in long COVID can induce NETs and protect them from degradation; whether NETs exert differential, organ-specific effects; specifically which NET components contribute to organ-specific pathologies, such as pulmonary fibrosis; and whether senescent cells can drive NET formation through their pro-inflammatory secretome in long COVID. Answering these questions may pave the way for the development of clinically applicable strategies targeting NETs, providing relief for this emerging health crisis.

Specialized pro-resolving mediators (SPMs) and especially Resolvin E1 (RvE1) can actively terminate inflammation and promote healing during lung diseases such as acute respiratory distress syndrome (ARDS). Although ARDS primarily affects the lung, many ARDS patients also develop neurocognitive impairments. To investigate the connection between the lung and brain during ARDS and the therapeutic potential of SPMs and its derivatives, fat-1 mice were crossbred with RvE1 receptor knockout mice. ARDS was induced in these mice by intratracheal application of lipopolysaccharide (LPS, 10 µg). Mice were sacrificed at 0 h, 4 h, 24 h, 72 h, and 120 h post inflammation, and effects on the lung, liver, and brain were assessed by RT-PCR, multiplex, immunohistochemistry, Western blot, and LC-MS/MS. Protein and mRNA analyses of the lung, liver, and hypothalamus revealed LPS-induced lung inflammation increased inflammatory signaling in the hypothalamus despite low signaling in the periphery. Neutrophil recruitment in different brain structures was determined by immunohistochemical staining. Overall, we showed that immune cell trafficking to the brain contributed to immune-to-brain communication during ARDS rather than cytokines. Deficiency in RvE1 receptors and enhanced omega-3 polyunsaturated fatty acid levels (fat-1 mice) affect lung-brain interaction during ARDS by altering profiles of several inflammatory and lipid mediators and glial activity markers.

Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury characterized by diffuse alveolar damage. The period prevalence of ARDS was 10.4% of ICU admissions in 50 countries. Although great progress has been made in supportive care, the hospital mortality rate of severe ARDS is still up to 46.1%. Moreover, up to now, there is no effective pharmacotherapy for ARDS and most clinical trials focusing on consistently effective drugs have met disappointing results. Mesenchymal stem cells (MSCs) and their derived extracellular vesicles (EVs) have spawned intense interest of a wide range of researchers and clinicians due to their robust anti-inflammatory, anti-apoptotic and tissue regeneration properties. A growing body of evidence from preclinical studies confirmed the promising therapeutic potential of MSCs and their EVs in the treatment of ARDS. Based on the inspiring experimental results, clinical trials have been designed to evaluate safety and efficacy of MSCs and their EVs in ARDS patients. Moreover, trials exploring their optimal time window and regimen of drug administration are ongoing. Therefore, this review aims to present an overview of the characteristics of mesenchymal stem cells and their derived EVs, therapeutic mechanisms for ARDS and research progress that has been made over the past 5 years.

Neutrophil granulocytes predominate in the lungs of patients infected with Mycobacterium tuberculosis (Mtb) in earlier stages of the disease. During infection, neutrophils release neutrophil extracellular traps (NETs), an antimicrobial mechanism by which a DNA-backbone spiked with antimicrobial components traps the mycobacteria. However, the specific mycobacterial factors driving NET formation remain unclear. Proteins from the proline-glutamic acid (PE)/proline-proline-glutamic acid (PPE) family are critical to Mtb pathophysiology and virulence.

Here, we investigated NET induction by PE18, PPE26, and PE31 in primary human blood-derived neutrophils. Neutrophils were stimulated with the respective proteins for 3h, and NET formation was subsequently assessed using confocal fluorescence microscopy. Intracellular ROS levels and cell necrosis were estimated by flow cytometry. Additionally, the influence of phorbol-12-myristate-13-acetate (PMA), a known NADPH oxidase enhancer, on NET formation was examined. Neutrophil integrity following incubation with the PE/PPE proteins was evaluated using transmission electron microscopy.

For the first time, we report that stimulation of primary human blood-derived neutrophils with Mtb proteins PE18, PPE26, and PE31 resulted in the formation of NETs, which correlated with an increase in intracellular ROS levels. Notably, the presence of PMA further amplified this effect. Following incubation with the PE/PPE proteins, neutrophils were found to remain viable and structurally intact, as verified through transmission electron microscopy, indicating the occurrence of vital NET formation.

These findings offer valuable insights that contribute to a better understanding of host-pathogen interactions during Mtb infection. Moreover, they underscore the significance of these particular Mtb antigens in triggering NET formation, representing a distinctive and previously unrecognized function of PE/PPE antigens.

Antibody-dependent enhancement (ADE) is a phenomenon where virus-specific antibodies paradoxically cause enhanced viral replication and/or excessive immune responses, leading to infection exacerbation, tissue damage, and multiple organ failure. ADE has been observed in many viral infections and is supposed to complicate the course of COVID-19. However, the evidence is insufficient. Since no specific laboratory markers have been described, the prediction and confirmation of ADE are very challenging. The only possible predictor is the presence of already existing (after previous infection) antibodies that can bind to viral epitopes and promote the disease enhancement. At the same time, the virus-specific antibodies are also a part of immune response against a pathogen. These opposite effects of antibodies make ADE research controversial. The assignment of immunoglobulins to ADE-associated or virus neutralizing is based on their affinity, avidity, and content in blood. However, these criteria are not clearly defined. Another debatable issue (rather terminological, but no less important) is that in most publications about ADE, all immunoglobulins produced by the immune system against pathogens are qualified as pre-existing antibodies, thus ignoring the conventional use of this term for natural antibodies produced without any stimulation by pathogens. Anti-glycan antibodies (AGA) make up a significant part of the natural immunoglobulins pool, and there is some evidence of their antiviral effect, particularly in COVID-19. AGA have been shown to be involved in ADE in bacterial infections, but their role in the development of ADE in viral infections has not been studied. This review focuses on pros and cons for AGA as an ADE trigger. We also present the results of our pilot studies, suggesting that AGAs, which bind to complex epitopes (glycan plus something else in tight proximity), may be involved in the development of the ADE phenomenon.

Acute lung injury is significantly associated with the aberrant activation and pyroptosis of alveolar macrophages. Targeting the GPR18 receptor presents a potential therapeutic approach to mitigate inflammation. Verbenalin, a prominent component of Verbena in Xuanfeibaidu (XFBD) granules, is recommended for treating COVID-19. In this study, we demonstrate the therapeutic effect of verbenalin on lung injury through direct binding to the GPR18 receptor. Verbenalin inhibits the activation of inflammatory signaling pathways induced by lipopolysaccharide (LPS) and IgG immune complex (IgG IC) via GPR18 receptor activation. The structural basis for verbenalin's effect on GPR18 activation is elucidated through molecular docking and molecular dynamics simulations. Furthermore, we establish that IgG IC induces macrophage pyroptosis by upregulating the expression of GSDME and GSDMD through CEBP-δ activation, while verbenalin inhibits this process. Additionally, we provide the first evidence that IgG IC promotes the formation of neutrophil extracellular traps (NETs), and verbenalin suppresses NETs formation. Collectively, our findings indicate that verbenalin functions as a "phytoresolvin" to promote inflammation regression and suggests that targeting the C/EBP-δ/GSDMD/GSDME axis to inhibit macrophage pyroptosis may represent a novel strategy for treating acute lung injury and sepsis.

Acute coronary syndrome (ACS) is a group of clinical syndromes caused by acute myocardial ischemia, which can cause heart failure, arrhythmia and even sudden death. It is the major cause of disability and death worldwide. Neutrophil extracellular traps (NETs) are reticular structures released by neutrophils activation and have various biological functions. NETs are closely related to the occurrence and development of ACS and also the subsequent damage after myocardial infarction. The mechanisms are complex and interdependent on various pathways, which require further exploration. This article reviewed the role and mechanism of NETs in ACS, thereby providing a valuable reference for the diagnosis and clinical treatment of ACS.