Neutrophil Extracellular Trap Density Increases With Increasing Histopathological Severity of Crohn's Disease

Evaluating the anti-inflammatory and antioxidant efficacy of complementary and alternative medicines (CAM) used for management of inflammatory bowel disease: a comprehensive review

Inflammatory bowel disease (IBD) is a chronic autoimmune condition whose pathogenesis has not been fully elucidated, and current treatments are not definitive and often carry several side effects. The Complementary and Alternative Medicine (CAM) offers a new approach to conventional medicine. However, their clinical application and mechanisms remain limited.Objective: The aim of this review is to evaluate the anti-inflammatory, impact on microbiota and antioxidant efficacy of currently available CAM for IBD.Methods: The literature collection was obtained from Google Scholar, MEDLINE, PubMed and Web of Science (WOS). Studies in both human and animal models, published in English language between 2018 and 2024, were selected. Sixty-seven studies were included in the current review after inclusion and exclusion screening processes.Results: Mostly, studies showed significant anti-inflammatory, gut microbiota restoring, antioxidant effects of polyphenols, polysaccharides, emodin, short-chain fatty acids (SCFA; including butyrate, propionate and acetate), and probiotics although some contrasting results were noted. Current evidence shows that polyphenols exhibit the most consistent result in alleviating IBD pathophysiology, primarily due to their significant SCFA-elevating effect.Discussion: Future studies may focus on human studies, narrowing down on individual factors which may change natural product's metabolism. Further research studies are also essential to obtain therapeutic recommendations.

Engineered Metal-Organic Frameworks for Targeted CRISPR/Cas9 Gene Editing

The development of precise and efficient delivery systems is pivotal for advancing CRISPR/Cas9 gene-editing technologies, particularly for therapeutic applications. Engineered metal-organic frameworks (MOFs) have emerged as a promising class of inorganic nonviral vectors, offering unique advantages such as tunable porosity, high cargo-loading capacity, and biocompatibility. This review explores the design and application of MOF-based nanoplatforms tailored for the targeted delivery of CRISPR/Cas9 components, aiming to enhance gene-editing precision and efficiency. By incorporating stimuli-responsive linkers and bioactive ligands, these MOFs enable controlled release of CRISPR/Cas9 payloads at the target site. Comparative discussions demonstrate superior performance of MOFs over conventional nonviral systems in terms of stability, transfection efficiency, and reduced off-target effects. Additionally, the intracellular trafficking mechanisms and the therapeutic potential of these platforms in preclinical models are discussed. These findings highlight the transformative potential of MOF-based delivery systems in overcoming the challenges associated with gene-editing technologies, such as immunogenicity and cytotoxicity, paving the way for their application in precision medicine. This review provides a blueprint for the integration of nanotechnology and genome editing, advancing the frontier of nonviral therapeutic delivery systems.

The crucial role of neutrophil extracellular traps and IL-17 signaling in indomethacin-induced gastric injury in mice

The homeostasis of gastric mucosa is extremely delicate. Neutrophils, the most abundant immune cells in human circulation, are regarded crutial in the regulation of gastric mucosal immune response. Non-steroidal anti-inflammatory drugs (NSAIDs) induced gastric injury is the second major reason for gastric ulcers. The relations between neutrophils and Indomethacin-induced gastric injury are not fully understood. A mouse model of gastric injury was established using Indomethacin, followed by proteomic analysis (raw data are available via ProteomeXchange with identifier PXD058482). GO functional annotations and KEGG pathway enrichment analysis were conducted on significant differential proteins. The formation of neutrophil extracellular traps (NETs) was observed using ELISA and immunofluorescence. TEM, Western blot and Real-time PCR were applied to observe programmed death of gastric epithelial cells (GECs), and ELISA was conducted to measure levels of TNF-α and IL-1β in the gastric tissue. Deoxyribonuclease 1 (DNase 1), a NETs inhibitor, was administered intraperitoneally to inhibit NETs formation. In vitro, neutrophils were isolated from peripheral blood of mice and co-cultured with mouse GECs cell line, different dosage of Indomethacin were added to the culture dish, the levels of inflammatory factors, formation of NETs and GECs programmed death were assessed in vitro. Poly morphonuclear neutrophils (PMN) were extracted from mouse peripheral blood and single-cell RNA-sequencing (scRNA-seq) was further applied (raw data are available via Genome Sequence Archive with identifier CRA020950) to explore the intracellular mechanism of NETs formation. ELISA and immunofluorescence were performed to validate expression of IL-17 signaling pathway. After Indomethacin gavage, obvious gastric injury was observed. Proteomic analysis indicated that NETs formation played a crucial role in Indomethacin-induced gastric injury. Compared to control group, Indomethacin treatment resulted in NETs formation, elevated levels of TNF-α and IL-1β and GECs programmed death. Inhibition of NETs significantly reduced inflammatory factor levels and mitigated gastric injury caused by indomethacin. In vitro, 200 µL, 400 µL and 600 µL of Indomethacin caused excessive NETs formation in neutrophils. Besides, Indomethacin-induced NETs formation led to GECs programmed death in vitro. scRNA-seq revealed that neutrophils enrichment in the peripheral blood of Indomethacin-induced gastric injury and IL-17 signaling might be the key intracellular of NETs formation. Expressions of neutrophil IL-17R and concentration of IL-17 were significantly higher in model group. NETs formation is pivotal in Indomethacin-induced gastric injury, contributing to programmed cell death of GECs and inflammation; IL-17 signaling might be the key intracellular mechanism of NETs formation.

Mendelian randomization study of circulating leukocytes counts reveals causal associations with inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic recurrent IBD, whose cause involves the interaction between genetic and environmental factors. Although there is a recognized link between immune response and IBD, the causal relationship between circulating immune cell counts and IBD remains controversial. This study aimed to elucidate the causal relationship between genetically predicted circulating immune cell counts and IBD. We conducted a bidirectional 2-sample Mendelian randomization (MR) study using aggregated statistics from genome-wide association studies. The causal relationship between 5 circulating leukocytes cells (monocytes, lymphocytes, eosinophils, basophils and neutrophils) counts and IBD, including ulcerative colitis (UC) and Crohn disease (CD) was analyzed. Horizontal pleiotropy test and heterogeneity test were used to ensure the stability of the results. Our findings indicated that monocytes, lymphocytes, eosinophils, and basophils count were not significantly associated with IBD, however, elevated circulating neutrophils count was significantly associated with higher risk of IBD [odds ratio (OR) = 1.0017; 95% confidence interval (CI) = 1.0004-1.003; P = .009] and UC [OR = 2.465; 95% CI = 1.236-4.916; P = .01]. In addition, we also found that IBD [OR: 12.07; 95% CI = 1.909-76.316; P = .008] and CD [OR = 1.014; 95% CI = 1.004-1.023; P = .005] were significantly associated with higher circulating neutrophils count in reverse MR. This MR study provides genetic evidence for the causal relationship between the genetically predicted increase in circulating neutrophils count and the risk of IBD (UC and CD). This finding stresses the need for further exploring physiological functions of neutrophils in order to develop effective strategies against IBD.

Advances in Extracellular Matrix-Associated Diagnostics and Therapeutics

The extracellular matrix (ECM) is the common denominator of more than 50 chronic diseases. Some of these chronic pathologies lead to enhanced tissue formation and deposition, whereas others are associated with increased tissue degradation, and some exhibit a combination of both, leading to severe tissue alterations. To develop effective therapies for diseases affecting the lung, liver, kidney, skin, intestine, musculoskeletal system, heart, and solid tumors, we need to modulate the ECM's composition to restore its organization and function. Across diverse organ diseases, there are common denominators and distinguishing factors in this fibroinflammatory axis, which may be used to foster new insights into drug development across disease indications. The 2nd Extracellular Matrix Pharmacology Congress took place in Copenhagen, Denmark, from 17 to 19 June 2024 and was hosted by the International Society of Extracellular Matrix Pharmacology. The event was attended by 450 participants from 35 countries, among whom were prominent scientists who brought together state-of-the-art research on organ diseases and asked important questions to facilitate drug development. We highlight key aspects of the ECM in the liver, kidney, skin, intestine, musculoskeletal system, lungs, and solid tumors to advance our understanding of the ECM and its central targets in drug development. We also highlight key advances in the tools and technology that enable this drug development, thereby supporting the ECM.

Microbial and Transcriptomic Landscape Associated With Neutrophil Extracellular Traps in Perianal Fistulizing Crohn's Disease

BACKGROUND

Perianal fistulizing Crohn's disease (pfCD) poses significant healing challenges, closely associated with neutrophil extracellular traps (NETs). This study aimed to investigate the microbe-host interactions influencing NETs in pfCD.

METHODS

From January 2019 to July 2022, patients with pfCD were screened at Ren Ji Hospital. Patients in remission following comprehensive treatment were recruited. We documented clinical characteristics, medication regimens, healing outcomes, and infliximab levels in fistula tissues. NET positivity was confirmed by positive results in citrullinated histone H3 (CitH3) enzyme-linked immunosorbent assay (ELISA) and dual immunofluorescence staining for myeloperoxidase and CitH3. Microbial and transcriptomic profiles from fistula tissues, obtained during surgery, were analyzed using 16S rRNA gene sequencing and RNA sequencing. Differences in microbiome and transcriptomic profiles were evaluated, and their relationships were assessed using Mantel's and Spearman's coefficients.

RESULTS

Significant differences in microbial communities were found between groups (P = .007). Representatively differential microbes such as Prevotella bivia, Streptococcus gordonii, and Bacteroides dorei were enriched in NETs-positive fistulas (P < .05). Functional analysis of microbes revealed reduced ubiquinol biosynthesis and butanoate production in NETs-negative fistulas (P < .05). Transcriptomic analysis indicated increased neutrophil and monocyte infiltration in NETs-positive fistulas, associated with pathways involving bacterial response, neutrophil chemotaxis, secretory processes, and peptidase activity (P < .05). Species prevalent in NETs-positive fistulas correlated positively with immune responses and wound healing pathways, whereas bacteria in NETs-negative fistulas correlated negatively. NETs were negatively associated with tissue infliximab levels (P = .001) and healing outcomes (P = .025).

CONCLUSIONS

Our findings reveal unique microbial and transcriptomic signatures associated with NETs in pfCD, highlighting their profound influence on clinical outcomes.

Neutrophils: From Inflammatory Bowel Disease to Colitis-Associated Colorectal Cancer

Inflammatory bowel disease (IBD) is a non-specific inflammatory disease of digestive tract, primarily manifesting as ulcerative colitis (UC) and Crohn's disease (CD). The precise etiology of IBD remains elusive. The interplay of genetic factors, environmental influences, and intestinal microbiota contributes to the establishment of an uncontrolled immune environment within the intestine, which can progressively lead to atypical hyperplasia and ultimately to malignancy over a long period. This colorectal malignant tumor that arises from chronic IBD is referred to as colitis-associated colorectal cancer (CAC). Dysregulation in the quantity and functionality of neutrophils plays a significant role in the onset, progression, and recurrence of IBD, as well as in the transition from IBD to CAC. Neutrophils affect the pathophysiology of IBD through various mechanisms, including the production of reactive oxygen species (ROS), degranulation, the release of inflammatory mediators and chemokines, and the formation of neutrophil extracellular traps (NETs). These processes can induce DNA mutations, thereby facilitating the development of colon cancer. Given the incomplete understanding of the disease mechanisms underlying IBD and CAC, effective treatment and prevention strategies remain challenging. Consequently, a comprehensive review of the functional roles of neutrophils in IBD and CAC is essential for advancing our understanding of IBD pathogenesis and identifying potential therapeutic targets.

Advancing Inflammatory Bowel Disease Treatment by Targeting the Innate Immune System and Precision Drug Delivery

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, involves chronic inflammation of the gastrointestinal tract. Current immune-modulating therapies are insufficient for 30-50% of patients or cause significant side effects, emphasizing the need for new treatments. Targeting the innate immune system and enhancing drug delivery to inflamed gut regions are promising strategies. Neutrophils play a central role in IBD by releasing reactive oxygen species (ROS) and neutrophil extracellular traps (NETs) -DNA-based structures with cytotoxic proteins-that contribute to mucosal damage and inflammation. Recent studies linking ROS production, DNA repair, and NET formation have identified NETs as potential therapeutic targets, with preclinical models showing positive outcomes from NET inhibition. Innovative oral drug delivery systems designed to target gut inflammation directly-without systemic absorption-could improve treatment precision and reduce side effects. Advanced formulations utilize properties such as particle size, surface modifications, and ROS-triggered release to selectively target the distal ileum and colon. A dual strategy that combines a deeper understanding of IBD pathophysiology to identify inflammation-related therapeutic targets with advanced drug delivery systems may offer significant promise. For instance, pairing NET inhibition with ROS-responsive nanocarriers could enhance treatment efficacy, though further research is needed. This synergistic approach has the potential to greatly improve outcomes for IBD patients.

The role of neutrophil extracellular traps in Crohn's disease

Crohn's disease (CD) is an idiopathic and chronic inflammation of the gastrointestinal (GI) tract. The underlying pathogenesis of CD is multifaceted, with complex interactions between genetic predisposition, environmental triggers, and abnormalities within the immune system. Neutrophil extracellular traps (NETs) have gained significant attention as a novel component in the pathogenesis of CD. NETs are intricate structures fashioned from DNA, histones, and granule proteins, and are actively released by neutrophils to entangle and eliminate pathogenic microbes. This review article delves into the intricate role of NETs in the pathogenesis of CD. We examine how NETs may serve as a pivotal mechanism for the recruitment of immune cells to the site of inflammation. NETs are known to influence the function of epithelial cells, which line the GI tract, potentially contributing to the structural integrity and barrier dysfunction observed in CD. NETs stimulate inflammation, a hallmark of the disease, by releasing pro-inflammatory molecules and activating immune cells. We also investigate the promising therapeutic potential of targeting NETs in CD. By intercepting the formation or function of NETs, it may be possible to mitigate the chronic inflammation, reduce tissue damage, and alleviate the symptoms associated with CD. Strategies to inhibit NET formation, such as the use of DNase I and approaches to disrupt NET-mediated signaling pathways, are discussed in CD therapeutics. Understanding the detailed mechanisms of NETs is crucial for the development of targeted treatments that could potentially revolutionize the management of CD.

Decreased NETosis-related regulators in neuromyelitis optica spectrum disorders after plasma exchange

OBJECTIVES

To investigate the impact of plasma exchange (PLEX) on NETosis-related regulators and their correlation with neurological improvement in NMOSD patients.

METHODS

Twelve aquaporin-4 antibodies seropositive NMOSD patients were enrolled. NETosis-related regulators (myeloperoxidase [MPO], citrullinated histone H3 [CIT-H3], peptidyl arginine deiminase 4 [PAD4], neutrophil elastase [NE], CD64), pro-inflammatory cytokines (IL-1, IL-6, IL-12, TNF-α) and anti-inflammatory cytokines (IL-10, TGF-β1) were quantitatively assessed before and after PLEX treatment. Clinical assessments included expanded disability status scale (EDSS) and visual outcome scale (VOS) scores.

RESULTS

Following PLEX, all patients showed symptom improvement, with 66.7 % achieving marked-to-moderate improvement (MMI) at 3 months. Key regulators, such as MPO, CIT-H3, PAD4, NE, and pro-inflammatory cytokines such as IL-1, IL-6, IL-12, and TNF-α, exhibited a statistically significant decrease immediately after the initial PLEX session (P < 0.05). Furthermore, CD64 levels demonstrated a substantial decline after the second PLEX session (P < 0.05). Conversely, the levels of anti-inflammatory cytokines, including IL-10 and TGF-β1, displayed an ascending trend post-PLEX. In clinical relevance analysis, among patients who reached MMI, the reductions in MPO, IL-1, and IL-6 exhibited statistically significant differences when compared to patients in the mild-to-no improvement group (P < 0.05). Pearson correlation analysis revealed that the percentage reduction in IL-6 levels after PLEX was positively correlated with the percentage reduction in patient EDSS/VOS scores (r = 0.638, P < 0.05).

CONCLUSIONS

This study highlights that reduced levels of NETosis-related regulators after PLEX contribute to clinical improvement, suggesting the potential involvement of NETosis in the acute neurological impairment observed in NMOSD.

Unraveling the intricacies of neutrophil extracellular traps in inflammatory bowel disease: Pathways, biomarkers, and promising therapies

The development of inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, involves various factors and is characterized by persistent inflammation of the mucosal lining. However, the role of neutrophils in this process remains controversial. Neutrophil extracellular traps (NETs), which consist of chromatin, antimicrobial proteins, and oxidative enzymes, are released by neutrophils to trap pathogens. They are also involved in various immune-mediated and vascular diseases. NETs act as a vital defense mechanisms at the gut-mucosal interface and are frequently exposed to bacterial, viral, and fungal threats. However, they can also contribute to inflammation and worsen imbalances in the gut bacteria. Recent studies have suggested that NETs have a significant impact on IBD development. Previous studies have shown increased levels of NETs in tissue and blood samples from patients with IBD, as well as in experimental colitis mouse models. Therefore, this review discusses how NETs are formed and their role in the pathophysiology of IBD. It discusses how NETs may lead to tissue damage and contribute to IBD-associated complications. Moreover, non-invasive biomarkers are needed to replace invasive procedures such as endoscopy to better evaluate the disease status. Given the crucial role of NETs in IBD progression, this review focuses on potential NET biomarkers that can help predict the evolution of IBD. Furthermore, this review identifies potential therapeutic targets for regulating NET production, which could expand the range of available treatment options for IBD.

The role of neutrophils in autoimmune diseases

Historically, neutrophils have been primarily regarded as short-lived immune cells that act as initial responders to antibacterial immunity by swiftly neutralizing pathogens and facilitating the activation of adaptive immunity. However, recent evidence indicates that their roles are considerably more complex than previously recognized. Neutrophils comprise distinct subpopulations and can interact with various immune cells, release granular proteins, and form neutrophil extracellular traps. These functions are increasingly recognized as contributing factors to tissue damage in autoimmune diseases. This review comprehensively examines the physiological functions and heterogeneity of neutrophils, their interactions with other immune cells, and their significance in autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid syndrome, antineutrophil cytoplasmic antibody-associated vasculitis, multiple sclerosis, and others. This review aims to provide a deeper understanding of the function of neutrophils in the development and progression of autoimmune disorders.

The emerging role of neutrophil extracellular traps in ulcerative colitis

Ulcerative colitis (UC) is characterized by chronic non-recessive inflammation of the intestinal mucosa involving both innate and adaptive immune responses. Currently, new targeted therapies are urgently needed for UC, and neutrophil extracellular traps (NETs) are new therapeutic options. NETs are DNA-based networks released from neutrophils into the extracellular space after stimulation, in which a variety of granule proteins, proteolytic enzymes, antibacterial peptides, histones, and other network structures are embedded. With the deepening of the studies on NETs, their regulatory role in the development of autoimmune and autoinflammatory diseases has received extensive attention in recent years. Increasing evidence indicates that excess NETs exacerbate the inflammatory response in UC, disrupting the structure and function of the intestinal mucosal barrier and increasing the risk of thrombosis. Although NETs are usually assigned a deleterious role in promoting the pathological process of UC, they also appear to have a protective role in some models. Despite such progress, comprehensive reviews describing the therapeutic promise of NETs in UC remain limited. In this review, we discuss the latest evidence for the formation and degradation of NETs, focusing on their double-edged role in UC. Finally, the potential implications of NETs as therapeutic targets for UC will be discussed. This review aims to provide novel insights into the pathogenesis and therapeutic options for UC.

Analysis of neutrophil extracellular trap-related genes in Crohn's disease based on bioinformatics

Crohn's disease (CD) presents with diverse clinical phenotypes due to persistent inflammation of the gastrointestinal tract. Its global incidence is on the rise. Neutrophil extracellular traps (NETs) are networks released by neutrophils that capture microbicidal proteins and oxidases targeting pathogens. Research has shown that NETs are implicated in the pathogenesis of several immune-mediated diseases such as rheumatoid arthritis, systemic lupus erythematosus and inflammatory bowel disease. The goal of this study was to identify a panel of NET-related genes to construct a diagnostic and therapeutic model for CD. Through analysis of the GEO database, we identified 1950 differentially expressed genes (DEGs) associated with CD. Gene enrichment and immune cell infiltration analyses indicate that neutrophil infiltrates and chemokine-related pathways are predominantly involved in CD, with other immune cells such as CD4 and M1 macrophages also playing a role in disease progression. Utilizing weighted gene co-expression network analysis (WGCNA) and protein-protein interaction (PPI) networks, we identified six hub genes (SPP1, SOCS3, TIMP1, IRF1, CXCL2 and CD274). To validate the accuracy of our model, we performed external validation with statistical differences(p < 0.05). Additionally, immunohistochemical experiments demonstrated higher protein expression of the hub genes in colonic tissues from CD patients compared to healthy subjects (p < 0.05). In summary, we identified six effective hub genes associated with NETs as potential diagnostic markers for CD. These markers not only offer targets for future research but also hold promise for the development of novel therapeutic interventions for CD.

Myeloperoxidase Gene Deletion Causes Drastic Microbiome Shifts in Mice and Does Not Mitigate Dextran Sodium Sulphate-Induced Colitis

Neutrophil-myeloperoxidase (MPO) is a heme-containing peroxidase which produces excess amounts of hypochlorous acid during inflammation. While pharmacological MPO inhibition mitigates all indices of experimental colitis, no studies have corroborated the role of MPO using knockout (KO) models. Therefore, we investigated MPO deficient mice in a murine model of colitis. Wild type (Wt) and MPO-deficient mice were treated with dextran sodium sulphate (DSS) in a chronic model of experimental colitis with three acute cycles of DSS-induced colitis over 63 days, emulating IBD relapse and remission cycles. Mice were immunologically profiled at the gut muscoa and the faecal microbiome was assessed via 16S rRNA amplicon sequencing. Contrary to previous pharmacological antagonist studies targeting MPO, MPO-deficient mice showed no protection from experimental colitis during cyclical DSS-challenge. We are the first to report drastic faecal microbiota shifts in MPO-deficient mice, showing a significantly different microbiome profile on Day 1 of treatment, with a similar shift and distinction on Day 29 (half-way point), via qualitative and quantitative descriptions of phylogenetic distances. Herein, we provide the first evidence of substantial microbiome shifts in MPO-deficiency, which may influence disease progression. Our findings have significant implications for the utility of MPO-KO mice in investigating disease models.

Polymeric DNase-I nanozymes targeting neutrophil extracellular traps for the treatment of bowel inflammation

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a family of chronic disorders along the gastrointestinal tract. Because of its idiopathic nature, IBD does not have a fundamental cure; current available therapies for IBD are limited to prolonged doses of immunomodulatory agents. While these treatments may reduce inflammation, limited therapeutic efficacy, inconsistency across patients, and adverse side effects from aggressive medications remain as major drawbacks. Recently, excessive production and accumulation of neutrophil extracellular traps (NETs) also known as NETosis have been identified to exacerbate inflammatory responses and induce further tissue damage in IBD. Such discovery invited many researchers to investigate NETs as a potential therapeutic target. DNase-I is a natural agent that can effectively destroy NETs and, therefore, potentially reduce NETs-induced inflammations even without the use of aggressive drugs. However, low stability and rapid clearance of DNase-I remain as major limitations for further therapeutic applications. In this research, polymeric nanozymes were fabricated to increase the delivery and therapeutic efficacy of DNase-I. DNase-I was immobilized on the surface of polymeric nanoparticles to maintain its enzymatic properties while extending its activity in the colon. Delivery of DNase-I using this platform allowed enhanced stability and prolonged activity of DNase-I with minimal toxicity. When administered to animal models of IBD, DNase-I nanozymes successfully alleviated various pathophysiological symptoms of IBD. More importantly, DNase-I nanozyme administration successfully attenuated neutrophil infiltration and NETosis in the colon compared to free DNase-I or mesalamine.

Thymopentin ameliorates experimental colitis via inhibiting neutrophil extracellular traps

BACKGROUND

The long-term prognosis of Crohn's disease (CD) remains unsatisfactory. Therefore, we assessed the therapeutic effect of thymopentin (TP5) in a mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis, which mimics CD, and analyzed its impact on neutrophil extracellular traps (NETs).

METHODS

NET markers, including myeloperoxidase (MPO), neutrophil elastase (NE), citrullinated histone H3 (CitH3), peptidyl arginine deiminase IV (PAD4), and double-stranded DNA (dsDNA) were assessed by immunostaining and enzyme-linked immunosorbent assay. NET formation was evaluated in vitro. Neoseptin 3, a specific NET agonist, was used to reverse the effect of TP5 on TNBS-induced colitis. The action mechanism of TP5 was investigated using RNA-seq.

RESULTS

TP5 ameliorated weight loss (P < 0.001), disease activity index (DAI) (P = 0.05), colon shrinkage (P = 0.04), and elevated levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, and neutrophils in the TNBS group. The TNBS group exhibited increased MPO, NE, CitH3, PAD4, dsDNA and MPO-DNA levels (all P < 0.001), which decreased after TP5 administration (P = 0.01, P < 0.001, P < 0.001, P < 0.001, P = 0.02, and P = 0.02 respectively). Tissue CitH3 levels were positively correlated with DAI and TNF-α levels (P < 0.05). Furthermore, phorbol 12-myristate 13-acetate-stimulated NET formation increased by 1.8-, 2.8-, and 2.3-fold in vitro in the control, TNBS + saline, and TNBS + TP5 groups, respectively. Neoseptin 3 significantly reversed the effect of TP5. RNA-seq revealed potential pathways underlying the effect of TP5.

CONCLUSION

TP5 effectively ameliorated colitis by suppressing NETs in the experimental CD model.

"Out of the box" new therapeutic strategies for Crohn´s disease: moving beyond biologics

New treatment options beyond immunosuppression have emerged in recent years for patients with Crohn´s disease (CD), a chronic systemic condition affecting primarily the gut with great impact in the quality of life. The cause of CD is largely unknown, and a curative treatment is not yet available. In addition, despite the growing therapeutic armamentarium in recent years almost half of the patients don´t achieve a sustained response over time. Thus, new therapeutic strategies are urgently needed. In this review, we discuss the current state of promising new "out of the box" possibilities to control chronic inflammation beyond current pharmacological treatments, including: exclusive enteral nutrition, specific diets, cell therapies using T regs, hyperbaric oxygen, fecal microbiota transplantation, phage therapy, helminths, cannabis and vagal nerve stimulation. The exploration of original and novel therapeutic modalities is key to address their potential as main or complementary treatments in selected CD populations in order to increase efficacy, minimize side effects and improve quality of life of patients.

Macrophage-Derived Extracellular Vesicles-Coated Palladium Nanoformulations Modulate Inflammatory and Immune Homeostasis for Targeting Therapy of Ulcerative Colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease mainly involving the colon and rectum, which features recurrent mucosal inflammation. The excessive production of reactive oxygen species (ROS) is a trigger for pathological changes such as cell apoptosis and disordered immune microenvironments, which are crucial for the progression of UC and can be a promising therapeutic target. Nowadays, the development of targeted therapeutic strategies for UC is still in its infancy. Thus, developing effective therapies based on ROS scavenging and elucidating their molecular pathways are urgently needed. Herein, a biomimetic nanoformulation (Pd@M) with cubic palladium (Pd) as the core and macrophage-derived extracellular vesicles (MEVs) as the shell is synthesized for the treatment of UC. These Pd@M nanoformulations exhibit multienzyme-like activities for effective ROS scavenging, excellent targeting ability as well as good biocompatibility. It is verified that Pd@M can regulate the polarization state of macrophages by inhibiting glycolysis, and decrease neutrophil infiltration and recruitment. In this way, the colonic inflammatory and immune microenvironment is remodeled, and apoptosis is prevented, ultimately improving colonic mucosal barrier function and alleviating colitis in the mouse model. This finding provides a promising alternative option for the treatment of UC patients.

Advances in proteomics: characterization of the innate immune system after birth and during inflammation

Proteomics is the characterization of the protein composition, the proteome, of a biological sample. It involves the large-scale identification and quantification of proteins, peptides, and post-translational modifications. This review focuses on recent developments in mass spectrometry-based proteomics and provides an overview of available methods for sample preparation to study the innate immune system. Recent advancements in the proteomics workflows, including sample preparation, have significantly improved the sensitivity and proteome coverage of biological samples including the technically difficult blood plasma. Proteomics is often applied in immunology and has been used to characterize the levels of innate immune system components after perturbations such as birth or during chronic inflammatory diseases like rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). In cancers, the tumor microenvironment may generate chronic inflammation and release cytokines to the circulation. In these situations, the innate immune system undergoes profound and long-lasting changes, the large-scale characterization of which may increase our biological understanding and help identify components with translational potential for guiding diagnosis and treatment decisions. With the ongoing technical development, proteomics will likely continue to provide increasing insights into complex biological processes and their implications for health and disease. Integrating proteomics with other omics data and utilizing multi-omics approaches have been demonstrated to give additional valuable insights into biological systems.

Role and Therapeutic Targeting Strategies of Neutrophil Extracellular Traps in Inflammation

Neutrophil extracellular traps (NETs) are large DNA reticular structures secreted by neutrophils and decorated with histones and antimicrobial proteins. As a key mechanism for neutrophils to resist microbial invasion, NETs play an important role in the killing of microorganisms (bacteria, fungi, and viruses). Although NETs are mostly known for mediating microbial killing, increasing evidence suggests that excessive NETs induced by stimulation of physical and chemical components, microorganisms, and pathological factors can exacerbate inflammation and organ damage. This review summarizes the induction and role of NETs in inflammation and focuses on the strategies of inhibiting NETosis and the mechanisms involved in pathogen evasion of NETs. Furthermore, herbal medicine inhibitors and nanodelivery strategies improve the efficiency of inhibition of excessive levels of NETs.

Myeloperoxidase in Health and Disease

Innate and adaptive immune responses comprise a complex network of protein-protein and protein-cell interactions that regulates commensal flora and protects organisms from foreign pathogens and transformed (proliferating) host cells under physiological conditions such as pregnancy, growth and development as well as formulating a response pathological challenge [...].

Neutrophil extracellular traps in tumor progression and immunotherapy

Tumor immunity is a growing field of research that involves immune cells within the tumor microenvironment. Neutrophil extracellular traps (NETs) are neutrophil-derived extracellular web-like chromatin structures that are composed of histones and granule proteins. Initially discovered as the predominant host defense against pathogens, NETs have attracted increasing attention due to they have also been tightly associated with tumor. Excessive NET formation has been linked to increased tumor growth, metastasis, and drug resistance. Moreover, through direct and/or indirect effects on immune cells, an abnormal increase in NETs benefits immune exclusion and inhibits T-cell mediated antitumor immune responses. In this review, we summarize the recent but rapid progress in understanding the pivotal roles of NETs in tumor and anti-tumor immunity, highlighting the most relevant challenges in the field. We believe that NETs may be a promising therapeutic target for tumor immunotherapy.

Dysregulated haemostasis in thrombo-inflammatory disease

Inflammatory disease is often associated with an increased incidence of venous thromboembolism in affected patients, although in most instances, the mechanistic basis for this increased thrombogenicity remains poorly understood. Acute infection, as exemplified by sepsis, malaria and most recently, COVID-19, drives 'immunothrombosis', where the immune defence response to capture and neutralise invading pathogens causes concurrent activation of deleterious prothrombotic cellular and biological responses. Moreover, dysregulated innate and adaptive immune responses in patients with chronic inflammatory conditions, such as inflammatory bowel disease, allergies, and neurodegenerative disorders, are now recognised to occur in parallel with activation of coagulation. In this review, we describe the detailed cellular and biochemical mechanisms that cause inflammation-driven haemostatic dysregulation, including aberrant contact pathway activation, increased tissue factor activity and release, innate immune cell activation and programmed cell death, and T cell-mediated changes in thrombus resolution. In addition, we consider how lifestyle changes increasingly associated with modern life, such as circadian rhythm disruption, chronic stress and old age, are increasingly implicated in unbalancing haemostasis. Finally, we describe the emergence of potential therapies with broad-ranging immunothrombotic functions, and how drug development in this area is challenged by our nascent understanding of the key molecular and cellular parameters that control the shared nodes of proinflammatory and procoagulant pathways. Despite the increasing recognition and understanding of the prothrombotic nature of inflammatory disease, significant challenges remain in effectively managing affected patients, and new therapeutic approaches to curtail the key pathogenic steps in immune response-driven thrombosis are urgently required.

Association of neutrophil extracellular traps with fistula healing in patients with complex perianal fistulising Crohn's disease

BACKGROUND AND AIMS

Perianal fistulising Crohn's disease (pfCD) is a disabling phenotype of Crohn's disease (CD) with suboptimal outcomes. We assessed neutrophil extracellular traps (NETs) in perianal fistulas and implicated their roles in pfCD healing.

METHODS

Patients with complex pfCD who developed preplaced seton drainage were recruited during the verified maintenance of remission in CD. Fistula tracts were sampled during definitive surgery plus seton removal. Patient demographics, CD classification, medication strategy, and healing of pfCD were recorded. RNA sequencing was applied for transcriptomic profile analysis. NETs components, including myeloperoxidase (MPO), neutrophil elastase (NE), and citrullinated histone H3 (CitH3), were identified using immunofluorescence. Serum infliximab (IFX), anti-IFX antibodies, and tissue levels of IFX, adalimumab (ADA), MPO and CitH3 were determined using enzyme-linked immunosorbent assays. Peptidyl arginine deiminase IV (PAD4), tumour necrosis factor (TNF)-α, and NE were detected using immunohistochemistry. Gene expression levels of PAD family members were assessed with qPCR.

RESULTS

Twenty-one patients were included, 15 of whom adopted IFX as maintenance treatment. RNA-seq revealed difference in neutrophil associated pathways between unhealed and healed fistulas. NETs components (MPO/NE/CitH3) were detectable in the fistulas and were parallel with the PAD4 levels. Eleven of 21 (52%) patients experienced complete healing of the pfCD 108 weeks post-operatively. Fistula NETs were significantly increased in patients with unhealed pfCD. Increased NETs were associated with abundant TNF-α production and the absence of IFX in fistulas.

CONCLUSIONS

NETs exist in pfCD fistulas, which are associated with unhealed post-operative fistulas in pfCD, suggesting their prognostic roles in pfCD.

Non-Canonical Functions of Myeloperoxidase in Immune Regulation, Tissue Inflammation and Cancer

Myeloperoxidase (MPO) is one of the most abundantly expressed proteins in neutrophils. It serves as a critical component of the antimicrobial defense system, facilitating microbial killing via generation of reactive oxygen species (ROS). Interestingly, emerging evidence indicates that in addition to the well-recognized canonical antimicrobial function of MPO, it can directly or indirectly impact immune cells and tissue responses in homeostatic and disease states. Here, we highlight the emerging non-canonical functions of MPO, including its impact on neutrophil longevity, activation and trafficking in inflammation, its interactions with other immune cells, and how these interactions shape disease outcomes. We further discuss MPO interactions with barrier forming endothelial and epithelial cells, specialized cells of the central nervous system (CNS) and its involvement in cancer progression. Such diverse function and the MPO association with numerous inflammatory disorders make it an attractive target for therapies aimed at resolving inflammation and limiting inflammation-associated tissue damage. However, while considering MPO inhibition as a potential therapy, one must account for the diverse impact of MPO activity on various cellular compartments both in health and disease.

Neutrophils in Intestinal Inflammation: What We Know and What We Could Expect for the Near Future

Neutrophils are short-lived cells that play a crucial role in inflammation. As in other tissues, these polymorphonuclear phagocytes are involved in the intestinal inflammatory response, on the one hand, contributing to the activation and recruitment of other immune cells, but on the other hand, facilitating intestinal mucosa repair by releasing mediators that aid in the resolution of inflammation. Even though these responses are helpful in physiological conditions, excessive recruitment of activated neutrophils in the gut correlates with increased mucosal damage and severe symptoms in patients with inflammatory bowel disease (IBD) and pre-clinical models of colitis. Thus, there is growing interest in controlling their biology to generate novel therapeutic approaches capable of reducing exacerbated intestinal inflammation. However, the beneficial and harmful effects of neutrophils on intestinal inflammation are still controversial. With this review, we summarise and discuss the most updated literature showing how neutrophils (and neutrophil extracellular traps) contribute to developing and resolving intestinal inflammation and their putative use as therapeutic targets.

Neutrophil extracellular traps accelerate vascular smooth muscle cell proliferation via Akt/CDKN1b/TK1 accompanying with the occurrence of hypertension

OBJECTIVE

Neutrophil extracellular traps (NETs) can trigger pathological changes in vascular cells or vessel wall components, which are vascular pathological changes of hypertension. Therefore, we hypothesized that NETs would be associated with the occurrence of hypertension.

METHODS

To evaluate the relationship between NETs and hypertension, we evaluated both the NETs formation in spontaneously hypertensive rats (SHRs) and the blood pressure of mice injected phorbol-12-myristate-13-acetate (PMA) via the tail vein to induce NETs formation in arterial wall. Meanwhile, proliferation and cell cycle of vascular smooth muscle cells (VSMCs), which were co-cultured with NETs were assessed. In addition, the role of exosomes from VSMCs co-cultured with NETs on proliferation signaling delivery was assessed.

RESULTS

Formation of NETs increased in the arteries of SHR. PMA resulted in up-regulation expression of citrullinated Histone H3 (cit Histone H3, a NETs marker) in the arteries of mice accompanied with increasing of blood pressure. NET treatment significantly increased VSMCs count and accelerated G1/S transition in vitro . Cyclin-dependent kinase inhibitor 1b (CDKN1b) was down-regulated and Thymidine kinase 1 (TK1) was up-regulated in VSMCs. Exosomes from VSMCs co-cultured with NETs significantly accelerated the proliferation of VSMCs. TK1 was up-regulated in the exosomes from VSMCs co-cultured with NETs and in both the arterial wall and serum of mice with PMA.

CONCLUSION

NETs promote VSMCs proliferation via Akt/CDKN1b/TK1 and is related to hypertension development. Exosomes from VSMCs co-cultured with NETs participate in transferring the proliferation signal. These results support the role of NETs in the development of hypertension.

Metabolic Reprogramming of Innate Immune Cells as a Possible Source of New Therapeutic Approaches in Autoimmunity

Immune cells undergo different metabolic pathways or immunometabolisms to interact with various antigens. Immunometabolism links immunological and metabolic processes and is critical for innate and adaptive immunity. Although metabolic reprogramming is necessary for cell differentiation and proliferation, it may mediate the imbalance of immune homeostasis, leading to the pathogenesis and development of some diseases, such as autoimmune diseases. Here, we discuss the effects of metabolic changes in autoimmune diseases, exerted by the leading actors of innate immunity, and their role in autoimmunity pathogenesis, suggesting many immunotherapeutic approaches.

Biomimetic MOF Nanoparticles Delivery of C-Dot Nanozyme and CRISPR/Cas9 System for Site-Specific Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) of unknown etiology affecting the colon and rectum. Previous studies have found that reactive oxygen species (ROS) overproduction and transmembrane glycoprotein CD98 (encoded by SLC3A2) upregulation played important roles in the initiation and progression of UC. On the basis of this, a biomimetic pH-responsive metal organic framework (MOF) carrier was constructed to deliver carbon nanodot-SOD nanozyme and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) system for site-specific treatment of UC. In this system, carbon nanodots (C-dots) and CD98 CRISPR/Cas9 plasmid were successfully encapsulated into MOF carrier (ZIF-8 nanoparticles) by a one-pot approach (formed as CCZ), and then camouflaged with macrophage membrane (formed as CCZM). It was worth noting that the C-dot nanozyme showed excellent superoxide dismutase (SOD) enzymatic activity, which could scavenge ROS effectively. As expected, this biomimetic system exhibited pH-responsive, immune escape, and inflammation targeting capability simultaneously. In vitro experiments showed that ROS was significantly eliminated, and CD98 was downregulated by CCZM. In the dextran sulfate sodium salt (DSS)-induced UC model, administration of CCZM significantly ameliorated the inflammation symptoms of mice, including the colon length and pathological parameters such as epithelium integrity and inflammation infiltration. In addition, both in vitro and in vivo results demonstrated that biomimetic nanoparticles effectively reduced the expression of pro-inflammatory cytokines. Overall, this study would provide a promising approach for the precise treatment of UC.