Targeted regulation of neutrophils is an effective approach for treating neutrophil-driven inflammatory diseases, but challenges remain in minimizing off-target effects and extending drug half-life. A DNA-based nanorobot was developed to target neutrophils by using an N-acetyl Pro-Gly-Pro (Ac-PGP) peptide to specifically bind to the C-X-C motif of chemokine receptor 2 (CXCR2) on neutrophil membranes. This robot (a tetrahedral framework nucleic acid modified with Ac-PGP, APT) identified and hitchhiked neutrophils to accumulate at inflammatory sites and prolong its half-lives, whilst also was internalized to influence the neutrophil cell cycle and maturation process to regulate oxidative stress, inflammation, migration, and recruitment in both in vivo and in vitro inflammation experiments. Consequently, the tissue damage caused by sepsis was greatly reduced. This novel neutrophil-based nanorobot highlights the high precision of targeting and regulating neutrophils, and presents a potential strategy for treating multiple neutrophil-driven diseases.

The need to understand key players driving pulmonary inflammation and fibrosis in COVID-19 patients leading to effective preventive strategies is imminent. Excessive neutrophil activation, including extracellular trap (NET) formation, is associated with severe COVID-19 and long-term sequelae. However, the clinical applications of neutrophil-targeting therapies are challenging due to short bioavailability and lack of cell-type specificity. This study presents a lipid nanoparticle (LNP) platform designed to deliver two established NET inhibitors, DNase I and Sivelestat (Siv) referred to as DPNLNPs, specifically to lung neutrophils. In vitro and in vivo experiments demonstrate that DPNLNPs preferentially accumulate in the lung neutrophils and degrade NETs as efficiently as the free DNase I and Siv. Additionally, administration of DPNLNPs in K18-hACE2 mice significantly inhibited SARS-CoV-2-induced NETs at a much lower dose than the free drugs and correlated with reduced lung and systemic inflammation, lung epithelium injury, and collagen deposition. Importantly, DPNLNP treatment only during the symptomatic phase of infection improved SARS-CoV-2 outcome revealing the complex role of NETs in COVID-19 pathogenesis. Together, this study serves as a proof-of-concept for adapting the LNP platform to deliver more than one immunomodulatory drug in a cell-specific manner to manage NET-associated complications in COVID-19 and other respiratory diseases.

NETosis, the process through which neutrophils release neutrophil extracellular traps (NETs), has emerged as a crucial mechanism in host defense and the pathogenesis of autoimmune responses. During the SARS-CoV-2 pandemic, this process received significant attention due to the central role of neutrophil recruitment and activation in infection control. However, elevated neutrophil levels and dysregulated NET formation have been linked to coagulopathy and endothelial damage, correlating with disease severity and poor prognosis in COVID-19. Moreover, it is known that SARS-CoV-2 can induce persistent low-grade systemic inflammation, known as long COVID, although the underlying causes remain unclear. It has been increasingly acknowledged that excessive NETosis and NET generation contribute to further pathophysiological abnormalities following SARS-CoV-2 infection. This review provides an updated overview of the role of NETosis in autoimmune diseases, but also the relationship between COVID-19 and long COVID with autoimmunity (e.g., latent and overt autoimmunity, molecular mimicry, epitope spreading) and NETosis (e.g., immune responses, NET markers). Finally, we discuss potential therapeutic strategies targeting dysregulated NETosis to mitigate the severe complications of COVID-19 and long COVID.

COVID-19 patients face an increased risk of thromboembolic complications, yet the exact pathophysiological role of platelets in the disease remains unclear. Considering the multifaceted nature of COVID-19 symptoms, including platelet hyperactivation and inflammation, the development of compounds that simultaneously target both represents a promising therapeutic strategy. The monoterpene 1.8-cineole (CNL-1976) is known for its anti-inflammatory and anti-aggregatory effects. Thus, understanding the mechanism behind platelet hyperactivation and the effect of 1.8-cineole during COVID-19 is crucial when aiming for a reduction of disease severity. In this study, we investigated the mechanism of platelet activation triggered by the SARS-CoV-2 S1 spike protein (S1). Utilizing S1-coupled beads, we discovered that platelet activation and aggregation were dependent on plasma components, particularly S1-specific IgG antibodies. The formation of immune complexes through IgG binding to S1 facilitated the crosslinking of the platelet expressed FcγRIIa receptor, initiating platelet activation and aggregation, as well as formation of platelet-leukocyte aggregates (PLAs). Importantly, treatment with 1.8-cineole significantly inhibited S1-bead-induced platelet activity and PLA formation. These findings strongly suggest that antibody-mediated platelet activation via FcγRIIa directly contributes to the well-recognized prothrombotic environment during COVID-19. Moreover, our data indicate that 1.8-cineole can serve as a potential therapeutic compound, alleviating platelet-driven thromboinflammatory complications associated with COVID-19 and post-acute sequelae of SARS-CoV-2 (PASC).

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.

Neutrophil extracellular traps (NETs) are a vital part of the innate immune response, while excessive NET formation can cause tissue damage. H3.1 nucleosomes, a component of NETs, have emerged as a potential biomarker. This study aimed to evaluate H3.1 nucleosomes in critical illness, assessing their relationship with sepsis, organ failure, inflammatory subphenotypes and outcomes.

The MARS cohort was used, comprising of consecutive Intensive Care Unit patients, with plasma samples collected on days 0, 2 and 4. H3.1 nucleosome concentrations were measured using the Nu.Q® NETs Immunoassay. H3.1 nucleosome concentrations were compared across sepsis presence and organ failure, both at baseline and longitudinally. The relationship between H3.1 nucleosome concentrations and clinical outcomes was investigated.

1713 critically ill patients were included, with a total of 3671 plasma samples. Baseline H3.1 nucleosome concentrations differed between sepsis confirmed by clinical adjudication (740 ng/mL), sepsis unconfirmed by clinical adjudication (416 ng/mL) and non-sepsis (463 ng/mL, P < 0.001). H3.1 concentrations were associated with SOFA score (r = 0.40) and were higher in patients with disseminated intravascular coagulation, acute kidney injury and hyperinflammatory sepsis. H3.1 concentration was highly predictive for the need of renal replacement therapy (hazard ratio 2.00 per log10 increase), correcting for mortality.

Sepsis and organ failure were closely associated with plasma H3.1 nucleosome concentrations. While individual diagnostic performance for sepsis and organ failure remained low, H3.1 levels predicted the need for renal replacement therapy and disseminated intravascular coagulation, revealing unique insights into the innate immune response.

ClinicalTrials.gov identifier NCT01905033; IRB number 10-056C, registered June 16, 2010.

Despite vaccines, rapidly mutating viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to threaten human health due to an impaired immunoregulatory pathway and a hyperactive immune response. Our understanding of the local immune mechanisms used by tissue-resident macrophages to safeguard the host from excessive inflammation during SARS-CoV-2 infection remains limited. Here, we found that nerve- and airway-associated interstitial macrophages (NAMs) are required to control mouse-adapted SARS-CoV-2 (MA-10) infection. Control mice restricted lung viral distribution and survived infection, whereas NAM depletion enhanced viral spread and inflammation and led to 100% mortality. Mechanistically, type I interferon receptor (IFNAR) signaling by NAMs was critical for limiting inflammation and viral spread, and IFNAR deficiency in CD169+ macrophages mirrored NAM-depleted outcomes and abrogated their expansion. These findings highlight the essential protective role of NAMs in regulating viral spread and inflammation, offering insights into SARS-CoV-2 pathogenesis and underscoring the importance of NAMs in mediating host immunity and disease tolerance.

It has been thought that neutrophil extracellular traps (NETs) and thrombosis exacerbate COVID-19, but, on the other hand, NETs are an important player in innate immunity. The precise roles of NETs and thrombosis in the course of COVID-19 have not been fully elucidated.

The roles were investigated in the literature and a new theory was formulated. When neutrophils encounter SARS-CoV-2 in the lung tissue, they undergo NETosis and capture the virus. This capture is triggered by electrostatic interaction between histones in NETs and SARS-CoV-2; histones are highly positively charged, and viruses, including SARS-CoV-2, have a net negative charge under physiological pH. NETs that capture SARS-CoV-2 fall into alveolar capillaries through the collapsed endothelium to spare the lung tissue from the toxicity of NETs. NETs in the microvessels cause microthrombosis; positively charged histones induce the aggregation of negatively charged platelets, which leads to microthrombi. Microthrombi engulfing SARS-CoV-2 are consolidated into fibrin clots, which are eventually degraded by increased fibrinolysis and eliminated from the circulation.

This novel theory suggests that NETosis and microthrombosis are phenomena inevitably elicited in COVID-19, and in combination they are a system newly termed "NETombosis". Undegraded fibrin clots remaining in the microcirculation may be the cause of the sequelae, because they cause long-lasting circulatory failure in various organs.

The soluble variant of the ectopeptidase CD13 (sCD13), released from the cell surface by matrix metalloproteinase 14 (MMP14), is a potent pro-inflammatory mediator, displaying chemotactic, angiogenic, and arthritogenic properties through bradykinin receptor B1 (B1R). We revealed a link between sCD13 and amplified neutrophil-mediated inflammatory responses in SARS-CoV-2 infection. sCD13 was markedly elevated in patients with COVID-19 and correlated with disease severity and variants, ethnicity, inflammation markers, and neutrophil extracellular trap formation (NETosis). Neutrophils treated with sCD13 showed heightened NETosis and chemotaxis, which were inhibited by sCD13 receptor blockade. Meanwhile sCD13 did not induce platelet aggregation. Single-cell analysis of COVID-19 lungs revealed coexpression of CD13 and MMP14 by various cell types, and higher CD13 expression compared with controls. Neutrophils with high CD13 mRNA were enriched for genes associated with immaturity, though CD13 protein expression was lower. Histological examination of COVID-19 lungs revealed CD13-positive leukocytes trapped in vessels with fibrin thrombi. Flow cytometry verified the presence of B1R and a second sCD13 receptor, protease-activated receptor 4, on monocytes and neutrophils. These findings identify sCD13 as a potential instigator of COVID-19-associated NETosis, potentiating vascular stress and thromboembolic complications. The potent pro-inflammatory effects of sCD13 may contribute to severe COVID-19, suggesting that sCD13 and its receptors might be therapeutic targets.

Inflammation and thrombosis are traditionally considered two separate entities of acute host responses to barrier breaks. While inciting inflammatory responses is a prerequisite to fighting invading pathogens and subsequent restoration of tissue homeostasis, thrombus formation is a crucial step of the hemostatic response to prevent blood loss following vascular injury. Though originally designed to protect the host, excessive induction of either inflammatory signaling or thrombus formation and their reciprocal activation contribute to a plethora of disorders, including cardiovascular, autoimmune, and malignant diseases. In this state-of-the-art review, we summarize recent insights into the intricate interplay of inflammation and thrombosis. We focus on the protective aspects of immunothrombosis as well as evidence of detrimental sequelae of thromboinflammation, specifically regarding recent studies that elucidate its pathophysiology beyond coronavirus disease 2019 (COVID-19). We introduce recently identified molecular aspects of key cellular players like neutrophils, monocytes, and platelets that contribute to both immunothrombosis and thromboinflammation. Further, we describe the underlying mechanisms of activation involving circulating plasma proteins and immune complexes. We then illustrate how these factors skew the inflammatory state toward detrimental thromboinflammation across cardiovascular as well as septic and autoimmune inflammatory diseases. Finally, we discuss how the advent of new technologies and the integration with clinical data have been used to investigate the mechanisms and signaling cascades underlying immunothrombosis and thromboinflammation. This review highlights open questions that will need to be addressed by the field to translate our mechanistic understanding into clinically meaningful therapeutic targeting.

Lung injury in COVID-19 is characterized by neutrophil invasion and the release of neutrophil extracellular traps (NETs). An aberrant NET formation may induce local inflammation and increase sputum viscosity. Inhalation of DNase I (dornase alfa) is a treatment option that degrades NETs in the airways. Previous case series have indicated positive clinical effects of inhaled dornase alfa.

Patients admitted to the hospital with acute COVID-19 and hypoxia (oxygen saturation <90%) were randomly assigned to receive aerosolized dornase alfa twice daily for 5 days or a placebo in addition to standard of care. The primary outcome was discharge from the hospital or an oxygen saturation >93% without respiratory support.

In total, 76 patients were randomized. The study was stopped when the Omicron virus variant appeared. The clinical response rate did not differ between patients receiving the active substance and placebo. Secondary outcomes were similar across groups, such as mortality, a new episode of hypoxia, length of stay in the hospital, and adverse events. A subanalysis of patients older or younger than 65 years showed no differences in primary or secondary outcomes.

Aerosolized dornase alfa failed to improve hypoxia in hospitalized patients with acute COVID-19. The study was conducted during a time of heterogeneity in viral variants and vaccination status of participants. Whether dornase alfa affects the outcomes in other respiratory infections requires further study.

Oxidative stress has been associated with COVID-19-related thrombotic complications. No investigations have explored nitric oxide (NO) and radical oxygen species (ROS) production by platelets. Indeed, activated platelets generate both NO and ROS which in turn regulate platelet function. The aim of the present study was to measure platelet NO and ROS production in COVID-19 patients, to assess whether they correlate with disease outcome and to clarify the mechanisms of platelet NO/ROS imbalance in COVID-19.Hospitalized mild and severe COVID-19 patients, age- and sex-matched healthy controls, and patients hospitalized in intensive care units for reasons different from COVID-19 were enrolled. Platelet NO and ROS production was assessed by flow cytometry. The oxidant and antioxidant capacity of COVID-19 plasma was assessed using lipid peroxidation and ORAC assays. The effect of COVID-19 plasma on platelet NO production and the impact of antioxidants on it were studied by flow cytometry.Platelets from COVID-19 patients displayed an altered NO/ROS balance, with defective NO and increased ROS production. Platelet NO production was significantly lower in patients who developed thrombotic events during hospitalization. COVID-19 patients showed significantly increased plasma lipid peroxidation and reduced antioxidant capacity compared with healthy controls. Concordantly, plasma from COVID-19 patients impaired NO production by healthy control species platelets, which was restored by the antioxidant agent Hydroxy-TEMPO.Our findings suggest that the unbalanced platelet NO/ROS production in COVID-19 plays a role in the thrombotic complications of SARS-CoV-2 infection. The restoration of platelet NO production may represent a therapeutic target for the prevention of thrombotic events in COVID-19 patients.

Neutrophil extracellular traps (NETs) are web-like structures released by neutrophils to trap and kill microbes. While NETs are crucial in host defense, excessive formation can lead to autoimmune diseases. Currently, no specific drugs target NETs directly; however, some medications can indirectly modulate their formation. The secretory leukocyte protease inhibitor (SLPI) is a small protein that inhibits the activity of neutrophil elastase (NE), an enzyme essential for NETs formation. By inhibiting NE activity, SLPI prevents the chromatin from decondensing, which is necessary for NETs to form; this suggests that SLPI may protect by preventing excessive NETs development. However, evidence indicates that NE can inactivate SLPI by cleaving its N-terminus. This action can create a protease/antiprotease imbalance, potentially leading to detrimental consequences for the host. In this study, we produced a recombinant variant of SLPI (SLPI-S15G-A16G: rSLPIv) using recombinant DNA technology, expressed in Escherichia coli SHuffle T7. The protein was tagged with the small metal-binding protein (SmbP) to facilitate its expression and purification through immobilized metal-affinity chromatography. Our results demonstrated that rSLPIv exhibited immunomodulatory activity at a concentration of 10 nM in neutrophils that had been prestimulated with PMA. It reduced NETs formation by 30 % and maintained this effect for up to 6 h. Confocal microscopy confirmed these findings, revealing a rSLPIv-dependent reduction in neutrophil nuclear expansion. Thus, rSLPIv shows significant suppressive activity on NETs formation at low concentrations, making it a potential candidate as an immunotherapeutic agent.

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.

Understanding the interplay among clinical variables-such as demographics, symptoms, and laboratory results-and their relationships with disease outcomes is critical for advancing diagnostics and understanding mechanisms in complex diseases. Existing methods fail to capture indirect or directional relationships, while existing Bayesian network learning methods are computationally expensive and only infer general associations without focusing on disease outcomes. Here we introduce random walk- and genetic algorithm-based network inference (RAMEN), a method for Bayesian network inference that uses absorbing random walks to prioritize outcome-relevant variables and a genetic algorithm for efficient network refinement. Applied to COVID-19 (Biobanque québécoise de la COVID-19), intensive care unit (ICU) septicemia (MIMIC-III), and COPD (CanCOLD) datasets, RAMEN reconstructs networks linking clinical markers to disease outcomes, such as elevated lactate levels in ICU patients. RAMEN demonstrates advantages in computational efficiency and scalability compared to existing methods. By modeling outcome-specific relationships, RAMEN provides a robust tool for uncovering critical disease mechanisms, advancing diagnostics, and enabling personalized treatment strategies.

Cytokine storm (CS) is a severe systemic inflammatory syndrome characterized by the excessive activation of immune cells and a significant increase in circulating levels of cytokines. This pathological process is implicated in the development of life-threatening conditions such as fulminant myocarditis (FM), acute respiratory distress syndrome (ARDS), primary or secondary hemophagocytic lymphohistiocytosis (HLH), cytokine release syndrome (CRS) associated with chimeric antigen receptor-modified T (CAR-T) therapy, and grade III to IV acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation. The significant involvement of the JAK-STAT pathway, Toll-like receptors, neutrophil extracellular traps, NLRP3 inflammasome, and other signaling pathways has been recognized in the pathogenesis of CS. Therapies targeting these pathways have been developed or are currently being investigated. While novel drugs have demonstrated promising therapeutic efficacy in mitigating CS, the overall mortality rate of CS resulting from underlying diseases remains high. In the clinical setting, the management of CS typically necessitates a multidisciplinary team strategy encompassing the removal of abnormal inflammatory or immune system activation, the preservation of vital organ function, the treatment of the underlying disease, and the provision of life supportive therapy. This review provides a comprehensive overview of the key signaling pathways and associated cytokines implicated in CS, elucidates the impact of dysregulated immune cell activation, and delineates the resultant organ injury associated with CS. In addition, we offer insights and current literature on the management of CS in cases of FM, ARDS, systemic inflammatory response syndrome, treatment-induced CRS, HLH, and other related conditions.

Extracellular DNA (eDNA) is crucial for the structural integrity of bacterial biofilms as they undergo transformation from B-DNA to Z-DNA as the biofilm matures. This transition to Z-DNA increases biofilm rigidity and prevents binding by canonical B-DNA-binding proteins, including nucleases. One of the primary defenses against bacterial infections are Neutrophil Extracellular Traps (NETs), wherein neutrophils release their own eDNA to trap and kill bacteria. Here we show that H-NS, a bacterial nucleoid associated protein (NAP) that is also released during biofilm development, is able to incapacitate NETs. Indeed, when exposed to human derived neutrophils, H-NS prevented the formation of NETs and lead to NET eDNA retraction in previously formed NETs. NETs that were exposed to H-NS also lost their ability to kill free-living bacteria which made H-NS an attractive therapeutic candidate for the control of NET-related human diseases. A model of H-NS release from biofilms and NET incapacitation is discussed.

Previous studies have indicated an association between neutrophil extracellular traps (NETs) and acute respiratory distress syndrome (ARDS). This study aimed to investigate the potential causal effects of NETs and NETs-related biomarkers on ARDS or vice-versa. A two-sample Mendelian randomization (MR) utilizing genome-wide association studies (GWAS) data was employed to analyze the causality. The primary analysis was conducted using inverse-variance weighted (IVW) methods; weighted median, MR-Egger, and weighted model methods were used to validate the results. Horizontal pleiotropy and outlier detection were assessed via MR-Egger and MR pleiotropy residual sum and outlier (MR-PRESSO), respectively; Cochran's Q test evaluated heterogeneity, while Leave-one-out analyses were used to evaluate the presence of predominant instrumental variables (IVs). IVW method suggested causal associations between genetically predicted IL-13 and a higher risk of ARDS [OR (95%CI) = 1.52 (1.03-2.23), P = 0.047], while there was no causal effect of other factors on ARDS (all P > 0.05). Also, ARDS had no effect on NETs and NETs-related biomarkers (all P > 0.05). Cochran's Q confirmed no significant heterogeneity. MR-Egger regression ruled out horizontal pleiotropy's influence, and MR-PRESSO analysis identified no outliers, reinforcing the study's findings. This MR study established a causal relationship between IL-13 and ARDS, suggesting its potential role as a therapeutic target and biomarker of ARDS. Future work should delve into the underlying mechanisms and clinical applications.

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious adverse reaction to chemotherapy with limited treatment options. Research has indicated that neutrophil extracellular traps (NETs) are critical for the pathogenesis of CIPN. LPS/HMGB1 serve as important inducers of NETs. Here, we aimed to target the inhibition of NET formation (NETosis) to alleviate CIPN.

Oxaliplatin (L-OHP) was used to establish a CIPN model. The mice were pretreated with fucoidan to investigate the therapeutic effect. SR-A1-/- mice were used to examine the role of scavenger receptor A1 (SR-A1) in CIPN. Bone marrow-derived macrophages (BMDMs) isolated from SR-A1-/- mice and WT mice were used to investigate the mechanism by which macrophage phagocytosis of NETs alleviates CIPN.

Clinically, we found that the contents of LPS, HMGB1 and NETs in the plasma of CIPN patients were significantly increased and positively correlated with the VAS score. Fucoidan decreased the LPS/HMGB1/NET contents and relieved CIPN in mice. Mechanistically, fucoidan upregulated SR-A1 expression and promoted the phagocytosis of LPS/HMGB1 by BMDMs. Fucoidan also facilitated the engulfment of NETs by BMDMs via the recognition and localization of SR-A1 and HMGB1. The therapeutic effects of fucoidan were abolished by SR-A1 knockout. RNA-seq analysis revealed that fucoidan increased sqstm1 (p62) gene expression. Fucoidan promoted the competitive binding of sqstm1 and Nrf2 to Keap1, increasing Nrf2 nuclear translocation and SR-A1 transcription. Additionally, the sequencing analysis (16 S) of microbial diversity revealed that fucoidan increased the gut microbiota diversity and abundance and increased the Bacteroides/Firmicutes ratio.

Altogether, fucoidan promotes the SR-A1-mediated phagocytosis of LPS/HMGB1/NETs and maintains gut microbial homeostasis, which may provide a potential therapeutic strategy for CIPN.

Immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cells are novel therapeutic strategies that enhance anticancer immunity by activating or engineering cancer-targeting T cells. The resulting hyperinflammation carries several side effects, ranging from autoimmune-like symptoms to cytokine release syndrome (CRS), with potentially severe consequences. Recent findings indicate that ICIs increase the risk of venous and arterial thromboembolic adverse events. Patients with prior VTE might be at higher risk of developing new events under ICI while other risk factors vary across studies. So far, data on CAR T-linked coagulopathies are limited. Hypofibrinogenemia in the presence of CRS is the most commonly observed dysregulation of hemostatic parameters. A rare but particularly severe adverse event is the development of disseminated intravascular coagulation activation, which can occur in the setting of CRS and may be linked to immune effector cell-associated hemophagocytic lymphohistiocytosis. While the increasing number of studies on thromboembolic complications and coagulation alterations under ICIs and CAR T therapies are concerning, these results might be influenced by the retrospective study design and the heterogeneous patient populations. Importantly, numerous promising new T cell-based immunotherapies are currently under investigation for various cancers and are expected to become very prominent therapy options in the near future. Therefore, coagulopathies and thrombosis under T cell-directed immuno- and anti-cancer therapies is important. Our review provides an overview of the current understanding of ICI- and CAR T-associated thromboembolism. We discuss pathogenic mechanisms of inflammation-associated coagulation activation and explore potential biomarkers for VTE.

COVID-19 patients may have residual pulmonary alterations after the acute disease, with fibrotic-like alterations. Since metalloproteinases (MMP) and their regulators may be involved in inflammation and abnormal repair processing, we aimed to investigate the correlations between MMP-9, a tissue inhibitor of metalloproteinases (TIMP-1) and chest CT abnormalities in acute phase and mid-term follow-up.

COVID-19 patients with plasma analyses and CT scans performed at acute onset and 3 months after discharge (T post) were evaluated. MMP-9, TIMP-1, and MMP-9/TIMP-1 ratio were analyzed. CT extents of COVID-19 pneumonia and fibrotic-like alterations were visually scored (score range 0-25). Spearman rank correlation analysis (p-value <.05) was computed between acute and mid-term plasma analyses and CT scores.

39 patients were enrolled. At hospital admission, MMP-9, TIMP-1, and MMP-9/TIMP-1 had a median of 240.5 ng/mL, 258.8 ng/mL, and 0.9. The median CT global and fibrotic-like scores were 9 and 6. At T post, MMP-9 and TIMP-1 were not statistically different (p-value <.05). There was a reduction of CT global score (p-value = .00007). A significant correlation was found between MMP-9 and CT global score at hospital admission (ρ = 0.456, p-value = .003) and between MMP-9/TIMP-1 ratio and CT global score at hospital admission (ρ = 0.406, p-value = .009). No other significant correlations were found between plasma enzymes and CT alterations, both in acute and mid-term follow-up.

MMP-9 plasma levels and MMP-9/TIMP-1 ratio correlate with lung involvement during the acute phase. None of the levels of MMP-9, TIMP-1, and MMP-9/TIMP-1 ratio may be adopted as predictors of residual pulmonary alterations in mid-term follow-up.

In this study, systemic and localized immunity induced by SARS-CoV-2 variants of concern or interest (VOC/VOI) was investigated. For that, serum and tracheal aspirate soluble chemokines, pro-inflammatory/regulatory cytokines, and growth factors were measured in severe COVID-19 patients under mechanical ventilation upon infection with different SARS-CoV-2 variants, namely Alpha, Gamma, Zeta, Delta and Omicron. Increased levels of soluble mediators were observed in serum from severe COVID-19 patients regardless of the variant. In tracheal aspirate samples, the patients infected with the Gamma, Zeta, Delta, and Omicron variants exhibited reduced levels of inflammatory cytokines when compared to those infected with the Alpha variant. The trend of lower cytokine levels was also observed in the serum of patients across these variants, except for the Delta variant. By using network analysis and cytokine storm signatures, the data confirmed that severe COVID-19 induced by different variants have a completely divergent pattern of connectivity in serum samples as well as tracheal aspirates. Patients infected with variants at later time points in the pandemic such as Omicron exhibited networks of weak central architecture in serum samples as compared to tracheal aspirates, with lower number of neighborhood connections and clusters of pro-inflammatory and regulatory cytokines. By and large, this study points out to important systemic and local divergences and to loss of airway localized immunity in severe COVID-19 patients infected with SARS-CoV-2 variants, which brings insight into understanding host responses and viral escape vis-à-vis the virus mutations and evolution.

A subset of coronavirus disease 2019 (COVID-19) patients develops severe symptoms, characterized by acute lung injury, endothelial dysfunction and microthrombosis. Viral infection and immune cell activation contribute to this phenotype. It is known that systemic inflammation, evidenced by circulating inflammatory factors in patient plasma, is also likely to be involved in the pathophysiology of severe COVID-19. Here, we evaluate whether systemic inflammatory factors can induce endothelial dysfunction and subsequent thromboinflammation. We use a microfluidic Vessel-on-Chip model lined by human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs), stimulate it with plasma from hospitalized COVID-19 patients and perfuse it with human whole blood. COVID-19 plasma exhibited elevated levels of inflammatory cytokines compared to plasma from healthy controls. Incubation of hiPSC-ECs with COVID-19 plasma showed an activated endothelial phenotype, characterized by upregulation of inflammatory markers and transcriptomic patterns of host defense against viral infection. Treatment with COVID-19 plasma induced increased platelet aggregation in the Vessel-on-Chip, which was associated partially with formation of neutrophil extracellular traps (NETosis). Our study demonstrates that factors in the plasma play a causative role in thromboinflammation in the context of COVID-19. The presented Vessel-on-Chip can enable future studies on diagnosis, prevention and treatment of severe COVID-19.

A previously healthy man in his 50s was admitted with severe COVID-19 pneumonia requiring extracorporeal membrane oxygenation (ECMO) support. He was found to have persistent eosinophilia, with a peak level of 7.5×109/L. He had received multiple courses of steroids, including dexamethasone and methylprednisolone, with no improvement. On day 47, hydrocortisone was initiated for the treatment of septic shock. This resulted in the normalisation of the eosinophil count, which correlated with radiographic and clinical improvement. The patient was transitioned off ECMO and eventually weaned off mechanical ventilation. Studies conducted using the patient's serum identified circulating autoantibodies, which induced neutrophil extracellular traps (NETosis) and eosinophil extracellular traps (EETosis). A varying response of the eosinophils to different corticosteroids was observed in vivo that corresponded with the ex vivo experiments. This case highlights an unrecognised phenomenon of differential response to corticosteroids in severe COVID-19. Furthermore, this is the first reported case of EETosis in COVID-19.

Nucleic acids from both self- and non-self-sources act as vital danger signals that trigger immune responses. Critical illnesses such as acute respiratory distress syndrome, sepsis, trauma and ischemia lead to the aberrant cytosolic accumulation and massive release of nucleic acids that are detected by antiviral innate immune receptors in the endosome or cytosol. Activation of receptors for deoxyribonucleic acids and ribonucleic acids triggers inflammation, a major contributor to morbidity and mortality in critically ill patients. In the past decade, there has been growing recognition of the therapeutic potential of targeting nucleic acid sensing in critical care. This review summarizes current knowledge of nucleic acid sensing in acute respiratory distress syndrome, sepsis, trauma and ischemia. Given the extensive research on nucleic acid sensing in common pathological conditions like cancer, autoimmune disorders, metabolic disorders and aging, we provide a comprehensive summary of nucleic acid sensing beyond critical illness to offer insights that may inform its role in critical conditions. Additionally, we discuss potential therapeutic strategies that specifically target nucleic acid sensing. By examining nucleic acid sources, sensor activation and function, as well as the impact of regulating these pathways across various acute diseases, we highlight the driving role of nucleic acid sensing in critical illness.

Neutrophils, conventionally regarded as a homogeneous immune cell population, have emerged as a heterogeneous group of cells with distinct gene profiles and immune properties. Activated neutrophils release a spectrum of bioactive substances, including cytokines, chemokines, proteolytic enzymes, reactive oxygen species and neutrophil extracellular traps (NETs), which are composed of decondensed DNA and antimicrobial proteins. NETs have a pivotal role in innate immunity, including in preventing the ascent of uropathogenic bacteria into the kidneys, as they efficiently trap pathogenic microorganisms. However, although indispensable for defence against pathogens, NETs also pose risks of self-damage owing to their cytotoxicity, thrombogenicity and autoantigenicity. Accordingly, neutrophils and NETs have been implicated in the pathogenesis of various disorders that affect the kidneys, including acute kidney injury, vasculitis, systemic lupus erythematosus, thrombotic microangiopathy and in various aetiologies of chronic kidney disease. Pathological alterations in the glomerular vascular wall can promote the infiltration of neutrophils, which can cause tissue damage and inflammation through their interactions with kidney-resident cells, including mesangial cells and podocytes, leading to local cell death. Targeting neutrophil activation and NET formation might therefore represent a new therapeutic strategy for these conditions.

Neutrophil extracellular traps (NETs) are promising promoters in venous thromboembolism (VTE). In the present study, we have investigated the potential thrombogenic role of NETs in colorectal cancer (CRC). A total of 583 patients with gastrointestinal malignancies who were diagnosed with or without VTE by extremities arteriovenous ultrasound and computed tomography were enrolled. The incidence of VTE in CRC was as high as 17.53%. In serological ELISA experiments, Cit-H3, myeloperoxidase, and cfDNA were significantly overexpressed in CRC patients with VTE compared with CRC patients without VTE and healthy individuals. Neutrophils from CRC patients with VTE produced appreciable amounts of NETs after stimulation with phorbol-12-myristate-13-acetate, which were lacking in CRC patients without VTE and healthy individuals. CfDNA was positively correlated with plasmin-α2-antiplasmin complex and tissue plasmin activator inhibitor-1 complex, and Cit-H3 was positively correlated with plasmin-α2-antiplasmin complex, suggesting that NETs are associated with increased fibrinolytic activity. We screened some NETs-related genes by analyzing several high-throughput sequencing datasets of VTE and NETs. FCGR1A was identified as the optimal target gene by pan-cancer expression analysis and survival analysis. FCGR1A was significantly overexpressed in the peripheral blood of CRC patients without VTE compared with healthy individuals and showed a positive correlation with cfDNA. Neutrophil-derived NETs were significantly reduced by FCGR1A inhibitor exposure. These findings indicate that NETs are actively involved in VTE in CRC. NETs are promising thrombotic marker and therapeutic target in CRC to prevent the thrombotic consequences of cancer.

Jing-Yin-Gu-Biao formula (JYGBF) is a Chinese medicine derived from Yupingfeng power, Huoxiangzhengqi powder and Yinqiao powder, and has been widely used to treat acute respiratory infections. This study aims to observe the effects of JYGBF against postinfluenza Staphylococcus aureus (S. aureus) infection.

A mouse model of secondary S. aureus infection following PR8 infection was established to evaluate the protective effects of JYGBF against postinfluenza Staphylococcus aureus (S. aureus) infection and related mechanisms were validated in vivo and in vitro.

The administration of JYGBF significantly ameliorated acute lung injury (ALI) and inhibited overactivated inflammatory response (MIP-2, IL-6, etc.) in mice with postinfluenza S. aureus infection. Single cell RNA-sequencing (scRNA-seq) data indicated that neutrophils had the highest cytokine score in lungs and JYGBF inhibited neutrophil chemotaxis, reactive oxygen species (ROS) biosynthesis and ERK1/2 cascades in neutrophils. Meanwhile, JYGBF inhibited the formation of neutrophil extracellular traps (NETs) in lungs, which is characterized by the production of ROS, peptidyl arginine deiminase 4 (PAD4), citrullinated histone H3 (CitH3), myeloperoxidase (MPO), neutrophil elastase (NE), S100A8/A9 and MPO-CitH3 colocalization. Moreover, JYGBF decreased platelet counts and the expression of its activated markers (CD62P and αIIbβ3) accompanied by the drop of fibrinogen (FIB) and fibrin degradation product (FDP), accounting for alleviating hypercoagulable state. JYGBF inhibited ERK1/2 phosphorylation in neutrophils and in lungs of infected mice. Acacetin, a critical compound from JYGBF, inhibited NET formation via downregulating ERK/ROS axis.

These results indicated that JYGBF inhibited NET formation and overactivated inflammatory response by suppressing ERK/ROS axis in neutrophils, thereby mitigating ALI and improving the hypercoagulable state during postinfluenza S. aureus infection. JYGBF could be considered a potent therapeutic agent for the prevention and treatment of postinfluenza bacterial infection.

The global impact of SARS-CoV-2 and its associated coronavirus disease (COVID-19) has necessitated urgent characterization of prognostic biomarkers. This study aimed to delineate the epidemiological and clinical predictors of mortality among hospitalized COVID-19 patients.

A retrospective cohort study was conducted on 123 patients with laboratory-confirmed COVID-19 admitted to Huoshenshan Hospital (Wuhan, China) from 1 February 2020 to 30 April 2020. Kaplan-Meier curve and multivariate Cox regression were used to assess the independent factors with survival time. Statistical significance was set at a p-value of <0.05.

The cohort exhibited a mortality rate of 49.6% (61/123), with the critical clinical type (HR = 7.970, p = 0.009), leukocytosis (HR = 3.408, p = 0.006), and lymphopenia (HR = 0.817, p = 0.038) emerging as independent predictors of reduced survival. Critical-type patients demonstrated significantly elevated inflammatory markers (neutrophils: 10.41 ± 6.23 × 109/L; CRP: 104.47 ± 29.18 mg/L) and coagulopathy (D-dimer: 5.21 ± 2.34 μg/ml) compared to non-critical cases. Deceased patients exhibited pronounced metabolic derangements, including hyperglycemia (9.81 ± 2.07 mmol/L) and hepatic dysfunction (ALP: 174.03 ± 30.13 U/L).

We revealed the epidemiological and clinical features of different clinical types of SARS-CoV-2 as summarized in this paper. We found that critical type, leukocyte, and lymphocyte are risk factors that affect survival time, which could be an early and helpful marker to improve management of COVID-19 patients.

In recent years, the incidence of acute respiratory distress syndrome (ARDS) has been gradually increasing. Despite advances in supportive care, ARDS remains a significant cause of morbidity and mortality in critically ill patients. ARDS is characterized by acute hypoxaemic respiratory failure with diffuse pulmonary inflammation and bilateral edema due to excessive alveolocapillary permeability in patients with non-cardiogenic pulmonary diseases. Over the past seven decades, our understanding of the pathology and clinical characteristics of ARDS has evolved significantly, yet it remains an area of active research and discovery. ARDS is highly heterogeneous, including diverse pathological causes, clinical presentations, and treatment responses, presenting a significant challenge for clinicians and researchers. In this review, we comprehensively discuss the latest advancements in ARDS research, focusing on its heterogeneity, pathophysiological mechanisms, and emerging therapeutic approaches, such as cellular therapy, immunotherapy, and targeted therapy. Moreover, we also examine the pathological characteristics of COVID-19-related ARDS and discuss the corresponding therapeutic approaches. In the face of challenges posed by ARDS heterogeneity, recent advancements offer hope for improved patient outcomes. Further research is essential to translate these findings into effective clinical interventions and personalized treatment approaches for ARDS, ultimately leading to better outcomes for patients suffering from ARDS.

The COVID-19 pandemic has significantly impacted global healthcare systems, revealed vulnerabilities and prompted a re-evaluation of medical practices. Acute complications from the virus, including cardiovascular and neurological issues, have underscored the necessity for timely medical interventions. Advances in diagnostic methods and personalized therapies have been pivotal in mitigating severe outcomes. Additionally, Long COVID has emerged as a complex challenge, affecting various body systems and leading to respiratory, cardiovascular, neurological, psychological, and musculoskeletal problems. This broad spectrum of complications highlights the importance of multidisciplinary management approaches that prioritize therapy, rehabilitation, and patient-centered care. Vulnerable populations such as paediatric patients, pregnant women, and immunocompromised individuals face unique risks and complications, necessitating continuous monitoring and tailored management strategies to reduce morbidity and mortality associated with COVID-19.

Neutrophils are the first line of defense against pathogens, most effectively by forming Neutrophil Extracellular Traps (NETs). Neutrophiles are further classified into several subpopulations during their development, eliminating pathogens through various mechanisms. However, due to the chaotic and uncontrolled immune response, NETs are often severely resulting in tissue damage and lung infections. The uncontrolled and poorly acknowledged host response regarding the cytokine storm is one of the major causes of severe COVID-19 conditions. Specifically, the increased formation of low-density neutrophils (LDNs), together with neutrophil extracellular traps (NETs) is closely linked with the severity and poor prognosis in patients with COVID-19. In this review, we discuss in detail the ontogeny of neutrophils at different stages and their recruitment and activation after infections, focusing on SARS-CoV-2. In addition, this chapter summarized the research progress on potential targeted drugs (NETs and Cytokine inhibitors) for neutrophil medical therapy and hoped to provide reference for the development of related therapeutic drugs for critically ill COVID-19 patients.

Although rare, vaccine-induced thrombotic thrombocytopenia (VITT) following adenoviral vector COVID-19 vaccination is a concerning and often severe adverse effect of vaccination. The generation of high antiplatelet factor 4 antibody titers promotes the formation of immune complexes capable of activating platelets and neutrophils through FcγRIIa.

Given that platelet-leukocyte aggregate formation and inflammasome activation are common features of thromboinflammatory diseases, we aimed to evaluate if these are also features of VITT.

Samples from a cohort of 57 postvaccination thrombosis patients and 28 age- and sex-matched unvaccinated individuals were used for ex vivo investigation of platelet-leukocyte aggregate formation and inflammasome activation.

Patients with clinical features of VITT presented elevated levels of activated caspase-1, interleukin-18, and interleukin-1β in the plasma. We also found that soluble factors in the plasma of VITT patients induce the formation of platelet-neutrophil aggregates but not platelet-monocyte or platelet T-cell aggregates, which are associated with increased caspase-1 activation in neutrophils ex vivo. Platelet-neutrophil aggregate formation was prevented through blockage of FcγRIIa with the neutralizing antibody IV.3 and through blockage of P-selectin or integrin αIIbβ3, also inhibiting caspase-1 activation. Additionally, MCC950, an NLRP3 inflammasome inhibitor, blocked caspase-1 activation.

Taken together, these data show that VITT plasma induces platelet-neutrophil aggregate formation in a FcγRIIa-dependent manner and that platelet-neutrophil interactions may contribute to thromboinflammation in VITT patients by supporting NLRP3 inflammasome activation. These data shed light on novel immunopathological events associated with inflammation and thrombosis in VITT patients.

Peptidyl arginine deiminases (PADs) and citrullinated H3 histone (H3Cit) play a crucial role in the inflammatory response. These components determine various clinical situations in COVID-2019 associated pneumonia. Single nucleotide polymorphisms (SNPs) in the genes PADI2 and PADI4 may influence the outcome of poorer patient outcomes. We analyze the association of circulating levels NETs biomarkers (PAD2, PAD4, and H3Cit) and the SNPs on PADI2 (rs1005753 and rs2235926) and PADI4 (rs11203366, rs11203367, and rs874881) in hospitalized patients with severe acute respiratory distress syndrome (ARDs) by SARS-CoV-2 pneumonia.

A cross-sectional study in 160 hospitalized patients with ARDs by SARS-CoV-2 pneumonia. The plasma levels of PAD2, PAD4, and H3Cit were determined by ELISA method. The SNPs were determined by qPCR using TaqMan probes. Logistic regression models and receiver operating characteristics (ROC) curve were used to assess the association and predictive value of PAD2, PAD4, and H3Cit plasma levels in outcome by ARDs by SARS-CoV-2 pneumonia.

PAD2, PAD4, and H3Cit concentrations were predictors of invasive mechanical ventilation (IMV) requirement and non-survival. PAD2 were associated with non-survival, while PAD4 and H3Cit were associated with requirement IMV. In addition, PAD2 and PAD4 concentrations were related with inflammation markers such as NLR, MLR, dNLR, SII, SIRI, AISI, and NHL. In the carriers of TT genotype of rs1005753 of PADI2 were associated with increased of H3Cit, while, the carriers of GTG/GTG haplotype of PADI4 was related to the presence of increased of PAD4 circulating levels.

SNPs in PADI2 and PADI4 have a significant influence on concentrations of PAD2, PAD4, and H3Cit, which are predictor markers of requirement IMV and non-survival in severe ARDS by SARS-CoV-2 pneumonia.

The coagulation and immune system, both essential physiological systems in the human body, are intricately interconnected and play a critical role in determining the overall health of patients. These systems collaborate via various shared regulatory pathways, such as the Tissue Factor (TF) Pathway. Immunological cells that express TF and generate pro-inflammatory cytokines have the ability to affect coagulation. Conversely, coagulation factors and processes have a reciprocal effect on immunological responses by stimulating immune cells and regulating their functions. These interconnected pathways play a role in both preserving well-being and contributing to a range of pathological disorders. The close relationship between blood clotting and inflammation in the development of vascular disease has become a central focus of clinical study. This research specifically examines the crucial elements of this interaction within the contexts of cardiovascular disease and acute coronary syndrome. Tissue factor, the primary trigger of the extrinsic coagulation pathway, has a crucial function by inducing a proinflammatory reaction through the activation of coagulation factors. This, in turn, initiates coagulation and subsequent cellular signalling pathways. Protease-activated receptors establish the molecular connection between coagulation and inflammation by interacting with activated clotting factors II, X, and VII. Thrombosis, a condition characterised by the formation of blood clots, is the most dreaded consequence of cardiovascular disorders and a leading cause of death globally. Consequently, it poses a significant challenge to healthcare systems. Antithrombotic treatments efficiently target platelets and the coagulation cascade, but they come with the inherent danger of causing bleeding. Furthermore, antithrombotics are unable to fully eliminate thrombotic events, highlighting a treatment deficiency caused by a third mechanism that has not yet been sufficiently addressed, namely inflammation. Understanding these connections may aid in the development of novel approaches to mitigate the harmful mutual exacerbation of inflammation and coagulation. Gaining a comprehensive understanding of the intricate interaction among these systems is crucial for the management of diseases and the creation of efficacious remedies. Through the examination of these prevalent regulatory systems, we can discover novel therapeutic approaches that specifically target these complex illnesses. This paper provides a thorough examination of the reciprocal relationship between the coagulation and immune systems, emphasising its importance in maintaining health and understanding disease processes. This review examines the interplay between inflammation and thrombosis and its role in the development of thrombotic disorders.