A Novel Peptidylarginine Deiminase 4 (PAD4) Inhibitor BMS-P5 Blocks Formation of Neutrophil Extracellular Traps and Delays Progression of Multiple Myeloma

Neutrophil Extracellular Traps: A Crucial Factor in Post-Surgical Abdominal Adhesion Formation

Post-surgical abdominal adhesions, although poorly understood, are highly prevalent. The molecular processes underlying their formation remain elusive. This review aims to assess the relationship between neutrophil extracellular traps (NETs) and the generation of postoperative peritoneal adhesions and to discuss methods for mitigating peritoneal adhesions. A keyword or medical subject heading (MeSH) search for all original articles and reviews was performed in PubMed and Google Scholar. It included studies assessing peritoneal adhesion reformation after abdominal surgery from 2003 to 2023. After assessing for eligibility, the selected articles were evaluated using the Critical Appraisal Skills Programme checklist for qualitative research. The search yielded 127 full-text articles for assessment of eligibility, of which 7 studies met our criteria and were subjected to a detailed quality review using the Critical Appraisal Skills Programme (CASP) checklist. The selected studies offer a comprehensive analysis of adhesion pathogenesis with a special focus on the role of neutrophil extracellular traps (NETs) in the development of peritoneal adhesions. Current interventional strategies are examined, including the use of mechanical barriers, advances in regenerative medicine, and targeted molecular therapies. In particular, this review emphasizes the potential of NET-targeted interventions as promising strategies to mitigate postoperative adhesion development. Evidence suggests that in addition to their role in innate defense against infections and autoimmune diseases, NETs also play a crucial role in the formation of peritoneal adhesions after surgery. Therefore, therapeutic strategies that target NETs are emerging as significant considerations for researchers. Continued research is vital to fully elucidate the relationship between NETs and post-surgical adhesion formation to develop effective treatments.

naRNA-LL37 composite DAMPs define sterile NETs as self-propagating drivers of inflammation

Neutrophil extracellular traps (NETs) are a key antimicrobial feature of cellular innate immunity mediated by polymorphonuclear neutrophils (PMNs). NETs counteract microbes but are also linked to inflammation in atherosclerosis, arthritis, or psoriasis by unknown mechanisms. Here, we report that NET-associated RNA (naRNA) stimulates further NET formation in naive PMNs via a unique TLR8-NLRP3 inflammasome-dependent pathway. Keratinocytes respond to naRNA with expression of psoriasis-related genes (e.g., IL17, IL36) via atypical NOD2-RIPK signaling. In vivo, naRNA drives temporary skin inflammation, which is drastically ameliorated by genetic ablation of RNA sensing. Unexpectedly, the naRNA-LL37 'composite damage-associated molecular pattern (DAMP)' is pre-stored in resting neutrophil granules, defining sterile NETs as inflammatory webs that amplify neutrophil activation. However, the activity of the naRNA-LL37 DAMP is transient and hence supposedly self-limiting under physiological conditions. Collectively, upon dysregulated NET release like in psoriasis, naRNA sensing may represent both a potential cause of disease and a new intervention target.

NETs: an extracellular DNA network structure with implication for cardiovascular disease and cancer

Cardiovascular (CV) diseases and tumors are best known for its high morbidity and mortality worldwide. There is a growing recognition of the association between CV diseases and tumorigenesis. In addition to CV damage caused by anti-tumor drugs and tumor-induced organ dysfunction, CV events themselves and their treatment may also have a role in promoting tumorigenesis. Therefore, Therefore, the diagnosis and treatment of the two kinds of diseases have entered the era of clinical convergence. Emerging evidence indicates significant biologic overlap between cancer and CV diseases, with the recognition of shared biologic mechanisms. Neutrophil extracellular traps (NETs) represent an immune mechanism of neutrophils promoting the development of tumors and their metastasis. It has been recently demonstrated that NETs exist in various stages of hypertension and heart failure, exacerbating disease progression. At present, most studies focus on the biological role of NETs in CV diseases and tumor respectively, and there are relatively few studies on the specific regulatory mechanisms and effects of NETs in cardiovascular diseases associated with tumors. In this narrative review, we summarize some recent basic and clinical findings on how NETs are involved in the pathogenesis of cardiovascular diseases associated with tumors. We also highlight that the development of treatments targeting NETs may be one of the effective ways to prevent and treat cardiovascular diseases associated with tumors.

Cyclic guanosine monophosphate-adenosine monophosphate synthetase/stimulator of interferon genes signaling aggravated corneal allograft rejection through neutrophil extracellular traps

The activation of innate immunity following transplantation has been identified as a crucial factor in allograft inflammation and rejection. However, the role of cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)/stimulator of interferon genes (STING) signaling-mediated innate immunity in the pathogenesis of allograft rejection remains unclear. Utilizing a well-established murine model of corneal transplantation, we demonstrated increased expression of cGAS and STING in rejected-corneal allografts compared with syngeneic (Syn) and normal (Nor) corneas, along with significant activation of the cGAS/STING pathway, as evidenced by the enhanced phosphorylation of TANK-binding kinase 1and interferon regulatory factor 3. Pharmacological and genetic inhibition of cGAS/STING signaling markedly delayed corneal transplantation rejection, resulting in prolonged survival time and reduced inflammatory infiltration. Furthermore, we observed an increase in the formation of neutrophil extracellular traps (NETs) in rejected allografts, and the inhibition of NET formation through targeting peptidylarginine deiminase 4 and DNase I treatment significantly alleviated immune rejection and reduced cGAS/STING signaling activity. Conversely, subconjunctival injection of NETs accelerated corneal transplantation rejection and enhanced the activation of the cGAS/STING pathway. Collectively, these findings demonstrate that NETs contribute to the exacerbation of allograft rejection via cGAS/STING signaling, highlighting the targeting of the NETs/cGAS/STING signaling pathway as a potential strategy for prolonging allograft survival.

Targeting neutrophil extracellular traps: A novel strategy in hematologic malignancies

Neutrophil extracellular traps (NETs) have emerged as a critical factor in malignant hematologic disease pathogenesis. These structures, comprising DNA, histones, and cytoplasmic proteins, were initially recognized for their role in immune defense against microbial threats. Growing evidence suggests that NETs contribute to malignant cell progression and dissemination, representing a double-edged sword. However, there is a paucity of reports on its involvement in hematological disorders. A comprehensive understanding of the intricate relationship between malignant cells and NETs is necessary to explore effective therapeutic strategies. This review highlights NET formation and mechanisms underlying disease pathogenesis. Moreover, we discuss recent advancements in targeted inhibitor development for selective NET disruption, empowering precise design and efficacious therapeutic interventions for malignant hematologic diseases.

Matrimeres are systemic nanoscale mediators of tissue integrity and function

Tissue barriers must be rapidly restored after injury to promote regeneration. However, the mechanism behind this process is unclear, particularly in cases where the underlying extracellular matrix is still compromised. Here, we report the discovery of matrimeres as constitutive nanoscale mediators of tissue integrity and function. We define matrimeres as non-vesicular nanoparticles secreted by cells, distinguished by a primary composition comprising at least one matrix protein and DNA molecules serving as scaffolds. Mesenchymal stromal cells assemble matrimeres from fibronectin and DNA within acidic intracellular compartments. Drawing inspiration from this biological process, we have achieved the successful reconstitution of matrimeres without cells. This was accomplished by using purified matrix proteins, including fibronectin and vitronectin, and DNA molecules under optimal acidic pH conditions, guided by the heparin-binding domain and phosphate backbone, respectively. Plasma fibronectin matrimeres circulate in the blood at homeostasis but exhibit a 10-fold decrease during systemic inflammatory injury in vivo . Exogenous matrimeres rapidly restore vascular integrity by actively reannealing endothelial cells post-injury and remain persistent in the host tissue matrix. The scalable production of matrimeres holds promise as a biologically inspired platform for regenerative nanomedicine.

4-(Phenylselanyl)-2H-chromen-2-one-Loaded Nanocapsule Suspension-A Promising Breakthrough in Pain Management: Comprehensive Molecular Docking, Formulation Design, and Toxicological and Pharmacological Assessments in Mice

Therapies for the treatment of pain and inflammation continue to pose a global challenge, emphasizing the significant impact of pain on patients' quality of life. Therefore, this study aimed to investigate the effects of 4-(Phenylselanyl)-2H-chromen-2-one (4-PSCO) on pain-associated proteins through computational molecular docking tests. A new pharmaceutical formulation based on polymeric nanocapsules was developed and characterized. The potential toxicity of 4-PSCO was assessed using Caenorhabditis elegans and Swiss mice, and its pharmacological actions through acute nociception and inflammation tests were also assessed. Our results demonstrated that 4-PSCO, in its free form, exhibited high affinity for the selected receptors, including p38 MAP kinase, peptidyl arginine deiminase type 4, phosphoinositide 3-kinase, Janus kinase 2, toll-like receptor 4, and nuclear factor-kappa β. Both free and nanoencapsulated 4-PSCO showed no toxicity in nematodes and mice. Parameters related to oxidative stress and plasma markers showed no significant change. Both treatments demonstrated antinociceptive and anti-edematogenic effects in the glutamate and hot plate tests. The nanoencapsulated form exhibited a more prolonged effect, reducing mechanical hypersensitivity in an inflammatory pain model. These findings underscore the promising potential of 4-PSCO as an alternative for the development of more effective and safer drugs for the treatment of pain and inflammation.

hRpn13 shapes the proteome and transcriptome through epigenetic factors HDAC8, PADI4, and transcription factor NF-κB p50

The anti-cancer target hRpn13 is a proteasome substrate receptor. However, hRpn13-targeting molecules do not impair its interaction with proteasomes or ubiquitin, suggesting other critical cellular activities. We find that hRpn13 depletion causes correlated proteomic and transcriptomic changes, with pronounced effects in myeloma cells for cytoskeletal and immune response proteins and bone-marrow-specific arginine deiminase PADI4. Moreover, a PROTAC against hRpn13 co-depletes PADI4, histone deacetylase HDAC8, and DNA methyltransferase MGMT. PADI4 binds and citrullinates hRpn13 and proteasomes, and proteasomes from PADI4-inhibited myeloma cells exhibit reduced peptidase activity. When off proteasomes, hRpn13 can bind HDAC8, and this interaction inhibits HDAC8 activity. Further linking hRpn13 to transcription, its loss reduces nuclear factor κB (NF-κB) transcription factor p50, which proteasomes generate by cleaving its precursor protein. NF-κB inhibition depletes hRpn13 interactors PADI4 and HDAC8. Altogether, we find that hRpn13 acts dually in protein degradation and expression and that proteasome constituency and, in turn, regulation varies by cell type.

A neutrophil extracellular trap-related risk score predicts prognosis and characterizes the tumor microenvironment in multiple myeloma

Multiple myeloma (MM) is a distinguished hematologic malignancy, with existing studies elucidating its interaction with neutrophil extracellular traps (NETs), which may potentially facilitate tumor growth. However, systematic investigations into the role of NETs in MM remain limited. Utilizing the single-cell dataset GSE223060, we discerned active NET cell subgroups, namely neutrophils, monocytes, and macrophages. A transcriptional trajectory was subsequently constructed to comprehend the progression of MM. Following this, an analysis of cellular communication in MM was conducted with a particular emphasis on neutrophils, revealing an augmentation in interactions albeit with diminished strength, alongside abnormal communication links between neutrophils and NK cells within MM samples. Through the intersection of differentially expressed genes (DEGs) between NET active/inactive cells and MM versus healthy samples, a total of 316 genes were identified. This led to the development of a 13-gene risk model for prognostic prediction based on overall survival, utilizing transcriptomics dataset GSE136337. The high-risk group manifested altered immune infiltration and heightened sensitivity to chemotherapy. A constructed nomogram for predicting survival probabilities demonstrated encouraging AUCs for 1, 3, and 5-year survival predictions. Collectively, our findings unveil a novel NET-related prognostic signature for MM, thereby providing a potential avenue for therapeutic exploration.

A variety of death modes of neutrophils and their role in the etiology of autoimmune diseases

Neutrophils are important in the context of innate immunity and actively contribute to the progression of diverse autoimmune disorders. Distinct death mechanisms of neutrophils may exhibit specific and pivotal roles in autoimmune diseases and disease pathogenesis through the orchestration of immune homeostasis, the facilitation of autoantibody production, the induction of tissue and organ damage, and the incitement of pathological alterations. In recent years, more studies have provided in-depth examination of various neutrophil death modes, revealing nuances that challenge conventional understanding and underscoring their potential clinical utility in diagnosis and treatment. This review explores the multifaceted processes and characteristics of neutrophil death, with a focus on tailored investigations within various autoimmune diseases. It also highlights the potential interplay between neutrophil death and the landscape of autoimmune disorders. The review encapsulates the pertinent pathways implicated in various neutrophil death mechanisms across diverse autoimmune diseases while also charts possible avenues for future research.

Neutrophil extracellular traps regulating tumorimmunity in hepatocellular carcinoma

As a component of the innate immune system, there is emerging evidence to suggest that neutrophils may play a critical role in the initiation and progression of hepatocellular carcinoma (HCC). Neutrophil extracellular traps (NETs) are web-like chromatin structures that protrude from the membranes during neutrophil activation. Recent research has shown that NETs, which are at the forefront of the renewed interest in neutrophil studies, are increasingly intertwined with HCC. By exploring the mechanisms of NETs in HCC, we aim to improve our understanding of the role of NETs and gain deeper insights into neutrophil biology. Therefore, this article provides a summary of key findings and discusses the emerging field of NETs in HCC.

Chitosan nanomedicine containing RGD peptide and PAD4 inhibitor based on phenyl boronate coupling inhibition of primary tumor growth and lung metastasis

Stimulus-responsive nanodrugs have been extensively studied and their structural changes in the cells are important for controlled intracellular drug release. Histone citrullination of peptidylarginine deiminase 4 (PAD4) regulates the expression of tumor suppressor genes. In our previous study, compounds such as YW3-56 (356) were developed as potent PAD4 inhibitors with excellent anti-tumor activity in vitro and in vivo. To enhance the antitumor activity and improve the bioavailability, we further optimized the structure by modifying the phenylboronic acid moiety to the PAD4 inhibitor (4B). Taking advantage of the oxidative stress responsiveness of the phenylboronic acid moiety, in this study, we covalently attached 4B to RGD sequence peptide modified chitosan (K-CRGDV) to construct this new oxidative stress responsive nanodrug (K-CRGDV-4B). The modification of RGD sequence peptide conferred the nanodrug the ability to actively target tumors. The release mechanism was verified by UV-Vis spectroscopy, NMR. The anti-tumor and anti-metastatic properties of K-CRGDV-4B were demonstrated by in vitro cytotoxicity assay and in vivo mouse Lewis lung cancer metastasis model. In addition, K-CRGDV-4B modulates the ratio of immune cells in LLC tumor-bearing mice. Immunosuppressive proteins such as PD1 were inhibited, while IFN-γ and IFN-β, which are stimulators of tumor immune responses, were upregulated. Overall, K-CRGDV-4B is a stimulus-responsive nanodrug that responds to the tumor microenvironment by inhibiting PAD4 activity, blocking the formation of neutrophil extracellular traps (NETs), and improving the tumor immune microenvironment.

Protein citrullination: inhibition, identification and insertion

Protein citrullination is a post-translational modification (PTM) that is catalysed by the protein arginine deiminase (PAD) family of enzymes. This PTM involves the transformation of an arginine residue into citrulline. Protein citrullination is associated with several physiological processes, including the epigenetic regulation of gene expression, neutrophil extracellular trap formation and DNA damage-induced apoptosis. Aberrant protein citrullination is relevant to several autoimmune and neurodegenerative diseases and certain forms of cancer. PAD inhibitors have shown remarkable efficacy in a range of diseases including rheumatoid arthritis (RA), lupus, atherosclerosis and ulcerative colitis. In RA, anti-citrullinated protein antibodies can be detected prior to disease onset and are thus a valuable diagnostic tool for RA. Notably, citrullinated proteins may serve more generally as biomarkers of specific disease states; however, the identification of citrullinated protein residues remains challenging owing to the small 1 Da mass change that occurs upon citrullination. Herein, we highlight the progress made so far in the development of pan-PAD and isozyme selective inhibitors as well as the identification of citrullinated proteins and the site-specific incorporation of citrulline into proteins. This article is part of the Theo Murphy meeting issue 'The virtues and vices of protein citrullination'.

Role of Peptidylarginine Deiminase 4 in Central Nervous System Diseases

The deimination or citrullination of arginine residues in the polypeptide chain by peptidylarginine deiminase 4 alters the charge state of the polypeptide chain and affects the function of proteins. It is one of the main ways of protein post-translational modifications to regulate its function. Peptidylarginine deiminase 4 is widely expressed in multiple tissues and organs of the body, especially the central nervous system, and regulates the normal development of organisms. The abnormal expression and activation of peptidylarginine deiminase 4 is an important pathological mechanism for the occurrence and development of central nervous system diseases such as multiple sclerosis, Alzheimer's disease, cerebral ischemia reperfusion injury, and glioblastoma.

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.

Diabetes-associated neutrophil NETosis: pathogenesis and interventional target of diabetic complications

Neutrophil extracellular traps (NETs) are known as extracellular fibers networks consisting of antimicrobial proteins and decondensated chromatin DNA released by activated neutrophils. NETosis is a NETs-induced neutrophilic cell death which is unique from necrosis or apoptosis. Besides its neutralizing pathogen, NETosis plays a crucial role in diabetes and diabetes-related complications. In patients with diabetes, NETs-releasing products are significantly elevated in blood, and these findings confirm the association of NETosis and diabetic complications, including diabetic wound healing, diabetic retinopathy, and atherosclerosis. This article briefly summarizes the mechanisms of NETosis and discusses its contribution to the pathogenesis of diabetes-related complications and suggests new therapeutic targets by some small molecule compounds.

Current insights into the role of citrullination in thrombosis

Protein citrullination is a post-translational modification of arginine that controls a diverse array of cellular processes, including gene regulation, protein stability, and neutrophil extracellular trap (NET) formation. Histone citrullination promotes chromatin decondensation and NET formation, a pro-inflammatory form of cell death that is aberrantly increased in numerous immune disorders. This review will provide insights into NETosis and how this novel form of cell death contributes to inflammatory diseases, with a particular emphasis on its role in thrombosis. We will also discuss recent efforts to develop PAD-specific inhibitors.

Immune Checkpoint Inhibitors, Small-Molecule Immunotherapies and the Emerging Role of Neutrophil Extracellular Traps in Therapeutic Strategies for Head and Neck Cancer

Immune checkpoint inhibitor (ICI) therapy has revolutionized the treatment of many cancer types, including head and neck cancers (HNC). When checkpoint and partner proteins bind, these send an "off" signal to T cells, which prevents the immune system from destroying tumor cells. However, in HNC, and indeed many other cancers, more people do not respond and/or suffer from toxic effects than those who do respond. Hence, newer, more effective approaches are needed. The challenge to durable therapy lies in a deeper understanding of the complex interactions between immune cells, tumor cells and the tumor microenvironment. This will help develop therapies that promote lasting tumorlysis by overcoming T-cell exhaustion. Here we explore the strengths and limitations of current ICI therapy in head and neck squamous cell carcinoma (HNSCC). We also review emerging small-molecule immunotherapies and the growing promise of neutrophil extracellular traps in controlling tumor progression and metastasis.

An African-Specific Variant of TP53 Reveals PADI4 as a Regulator of p53-Mediated Tumor Suppression

TP53 is the most frequently mutated gene in cancer, yet key target genes for p53-mediated tumor suppression remain unidentified. Here, we characterize a rare, African-specific germline variant of TP53 in the DNA-binding domain Tyr107His (Y107H). Nuclear magnetic resonance and crystal structures reveal that Y107H is structurally similar to wild-type p53. Consistent with this, we find that Y107H can suppress tumor colony formation and is impaired for the transactivation of only a small subset of p53 target genes; this includes the epigenetic modifier PADI4, which deiminates arginine to the nonnatural amino acid citrulline. Surprisingly, we show that Y107H mice develop spontaneous cancers and metastases and that Y107H shows impaired tumor suppression in two other models. We show that PADI4 is itself tumor suppressive and that it requires an intact immune system for tumor suppression. We identify a p53-PADI4 gene signature that is predictive of survival and the efficacy of immune-checkpoint inhibitors.

SIGNIFICANCE

We analyze the African-centric Y107H hypomorphic variant and show that it confers increased cancer risk; we use Y107H in order to identify PADI4 as a key tumor-suppressive p53 target gene that contributes to an immune modulation signature and that is predictive of cancer survival and the success of immunotherapy. See related commentary by Bhatta and Cooks, p. 1518. This article is highlighted in the In This Issue feature, p. 1501.

Deciphering the role of NETosis-related signatures in the prognosis and immunotherapy of soft-tissue sarcoma using machine learning

Background: Soft-tissue sarcomas (STSs) are a rare type of cancer, accounting for about 1% of all adult cancers. Treatments for STSs can be difficult to implement because of their diverse histological and molecular features, which lead to variations in tumor behavior and response to therapy. Despite the growing importance of NETosis in cancer diagnosis and treatment, researches on its role in STSs remain limited compared to other cancer types. Methods: The study thoroughly investigated NETosis-related genes (NRGs) in STSs using large cohorts from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis and Support Vector Machine Recursive Feature Elimination (SVM-RFE) were employed for screening NRGs. Utilizing single-cell RNA-seq (scRNA-seq) dataset, we elucidated the expression profiles of NRGs within distinct cellular subpopulations. Several NRGs were validated by quantitative PCR (qPCR) and our proprietary sequencing data. To ascertain the impact of NRGs on the sarcoma phenotype, we conducted a series of in vitro experimental investigations. Employing unsupervised consensus clustering analysis, we established the NETosis clusters and respective NETosis subtypes. By analyzing DEGs between NETosis clusters, an NETosis scoring system was developed. Results: By comparing the outcomes obtained from LASSO regression analysis and SVM-RFE, 17 common NRGs were identified. The expression levels of the majority of NRGs exhibited notable dissimilarities between STS and normal tissues. The correlation with immune cell infiltration were demonstrated by the network comprising 17 NRGs. Patients within various NETosis clusters and subtypes exhibited different clinical and biological features. The prognostic and immune cell infiltration predictive capabilities of the scoring system were deemed efficient. Furthermore, the scoring system demonstrated potential for predicting immunotherapy response. Conclusion: The current study presents a systematic analysis of NETosis-related gene patterns in STS. The results of our study highlight the critical role NRGs play in tumor biology and the potential for personalized therapeutic approaches through the application of the NETosis score model in STS patients.

Neutrophil sub-types in maintaining immune homeostasis during steady state, infections and sterile inflammation

INTRODUCTION

Neutrophils are component of innate immune system and a) eliminate pathogens b) maintain immune homeostasis by regulating other immune cells and c) contribute to the resolution of inflammation. Neutrophil mediated inflammation has been described in pathogenesis of various diseases. This indicates neutrophils do not represent homogeneous population but perform multiple functions through confined subsets. Hence, in the present review we summarize various studies describing the heterogeneous nature of neutrophils and associated functions during steady state and pathological conditions.

METHODOLOGY

We performed extensive literature review with key words 'Neutrophil subpopulations' 'Neutrophil subsets', Neutrophil and infections', 'Neutrophil and metabolic disorders', 'Neutrophil heterogeneity' in PUBMED.

RESULTS

Neutrophil subtypes are characterized based on buoyancy, cell surface markers, localization and maturity. Recent advances in high throughput technologies indicate the existence of functionally diverse subsets of neutrophils in bone marrow, blood and tissues in both steady state and pathological conditions. Further, we found proportions of these subsets significantly vary in pathological conditions. Interestingly, stimulus specific activation of signalling pathways in neutrophils have been demonstrated.

CONCLUSION

Neutrophil sub-populations differ among diseases and hence, mechanisms regulating formation, sustenance, proportions and functions of these sub-types vary between physiological and pathological conditions. Hence, mechanistic insights of neutrophil subsets in disease specific manner may facilitate development of neutrophil-targeted therapies.

Leveraging histone glycation for cancer diagnostics and therapeutics

Cancer cells undergo metabolic reprogramming to rely mostly on aerobic glycolysis (the Warburg effect). The increased glycolytic intake enhances the intracellular levels of reactive sugars and sugar metabolites. These reactive species can covalently modify macromolecules in a process termed glycation. Histones are particularly susceptible to glycation, resulting in substantial alterations to chromatin structure, function, and transcriptional output. Growing evidence suggests a link between dysregulated metabolism of tumors and cancer proliferation through epigenetic changes. This review discusses recent advances in the understanding of histone glycation, its impact on the epigenetic landscape and cellular fate, and its role in cancer. In addition, we investigate the possibility of using histone glycation as biomarkers and targets for anticancer therapeutics.

NETs-Induced Thrombosis Impacts on Cardiovascular and Chronic Kidney Disease

Arterial and venous thrombosis constitute a major source of morbidity and mortality worldwide. Association between thrombotic complications and cardiovascular and other chronic inflammatory diseases are well described. Inflammation and subsequent initiation of thrombotic events, termed immunothrombosis, also receive growing attention but are still incompletely understood. Nevertheless, the clinical relevance of aberrant immunothrombosis, referred to as thromboinflammation, is evident by an increased risk of thrombosis and cardiovascular events in patients with inflammatory or infectious diseases. Proinflammatory mediators released from platelets, complement activation, and the formation of NETs (neutrophil extracellular traps) initiate and foster immunothrombosis. In this review, we highlight and discuss prominent and emerging interrelationships and functions between NETs and other mediators in immunothrombosis in cardiovascular disease. Also, with patients with chronic kidney disease suffering from increased cardiovascular and thrombotic risk, we summarize current knowledge on neutrophil phenotype, function, and NET formation in chronic kidney disease. In addition, we elaborate on therapeutic targeting of NETs-induced immunothrombosis. A better understanding of the functional relevance of antithrombotic mediators which do not increase bleeding risk may provide opportunities for successful therapeutic interventions to reduce thrombotic risk beyond current treatment options.

Anti-Citrullinated Protein Antibody Reactivity towards Neutrophil-Derived Antigens: Clonal Diversity and Inter-Individual Variation

Background: Why the adaptive immune system turns against citrullinated antigens in rheumatoid arthritis (RA) and whether anti-citrullinated protein antibodies (ACPAs) contribute to pathogenesis are questions that have triggered intense research, but still are not fully answered. Neutrophils may be crucial in this context, both as sources of citrullinated antigens and also as targets of ACPAs. To better understand how ACPAs and neutrophils contribute to RA, we studied the reactivity of a broad spectrum of RA patient-derived ACPA clones to activated or resting neutrophils, and we also compared neutrophil binding using polyclonal ACPAs from different patients. Methods: Neutrophils were activated by Ca2+ ionophore, PMA, nigericin, zymosan or IL-8, and ACPA binding was studied using flow cytometry and confocal microscopy. The roles of PAD2 and PAD4 were studied using PAD-deficient mice or the PAD4 inhibitor BMS-P5. Results: ACPAs broadly targeted NET-like structures, but did not bind to intact cells or influence NETosis. We observed high clonal diversity in ACPA binding to neutrophil-derived antigens. PAD2 was dispensable, but most ACPA clones required PAD4 for neutrophil binding. Using ACPA preparations from different patients, we observed high patient-to-patient variability in targeting neutrophil-derived antigens and similarly in another cellular effect of ACPAs, the stimulation of osteoclast differentiation. Conclusions: Neutrophils can be important sources of citrullinated antigens under conditions that lead to PAD4 activation, NETosis and the extrusion of intracellular material. A substantial clonal diversity in targeting neutrophils and a high variability among individuals in neutrophil binding and osteoclast stimulation suggest that ACPAs may influence RA-related symptoms with high patient-to-patient variability.

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.

Molecular Mechanisms of Neutrophil Extracellular Trap (NETs) Degradation

Although many studies have been exploring the mechanisms driving NETs formation, much less attention has been paid to the degradation and elimination of these structures. The NETs clearance and the effective removal of extracellular DNA, enzymatic proteins (neutrophil elastase, proteinase 3, myeloperoxidase) or histones are necessary to maintain tissue homeostasis, to prevent inflammation and to avoid the presentation of self-antigens. The persistence and overabundance of DNA fibers in the circulation and tissues may have dramatic consequences for a host leading to the development of various systemic and local damage. NETs are cleaved by a concerted action of extracellular and secreted deoxyribonucleases (DNases) followed by intracellular degradation by macrophages. NETs accumulation depends on the ability of DNase I and DNAse II to hydrolyze DNA. Furthermore, the macrophages actively engulf NETs and this event is facilitated by the preprocessing of NETs by DNase I. The purpose of this review is to present and discuss the current knowledge about the mechanisms of NETs degradation and its role in the pathogenesis of thrombosis, autoimmune diseases, cancer and severe infections, as well as to discuss the possibilities for potential therapeutic interventions. Several anti-NETs approaches had therapeutic effects in animal models of cancer and autoimmune diseases; nevertheless, the development of new drugs for patients needs further study for an effective development of clinical compounds that are able to target NETs.

Neutrophil extracellular traps primed intercellular communication in cancer progression as a promising therapeutic target

In addition to the anti-infection response, neutrophils are linked to tumor progression through the secretion of inflammation components and neutrophil extracellular traps (NETs) formation. NET is a web-like structure constituted by a chromatin scaffold coated with specific nuclear and cytoplasmic proteins, such as histone and granule peptides. Increasing evidence has demonstrated that NETs are favorable factors to promote tumor growth, invasion, migration, and immunosuppression. However, the cell-cell interaction between NETs and other cells (tumor cells and immune cells) is complicated and poorly studied. This work is the first review to focus on the intercellular communication mediated by NETs in cancer. We summarized the complex cell-cell interaction between NETs and other cells in the tumor microenvironment. We also address the significance of NETs as both prognostic/predictive biomarkers and molecular targets for cancer therapy. Moreover, we presented a comprehensive landscape of cancer immunity, improving the therapeutic efficacy for advanced cancer in the future.

Alleviation of arthritis through prevention of neutrophil extracellular traps by an orally available inhibitor of protein arginine deiminase 4

Protein arginine deiminases (PAD) 4 is an enzyme that catalyzes citrullination of protein and its role in autoimmune diseases has been established through clinical genetics and gene knock out studies in mice. Further, studies with PAD4 - deficient mice have shown that PAD4 deficiency does not lead to increased infection or immune suppression, which makes PAD4 an attractive therapeutic target for auto-immune and inflammatory diseases. PAD4 has critical enzymatic role of promoting chromatin decondensation and neutrophil extracellular traps (NETs) formation that is associated with a number of immune-mediated pathological conditions. Here, we present a non-covalent PAD4 inhibitor JBI-589 with high PAD4 isoform selectivity and delineated its binding mode at 2.88 Å resolution by X-ray crystallography. We confirmed its effectiveness in inhibiting NET formation in vitro. Additionally, by using two mouse arthritis models for human rheumatoid arthritis (RA), the well-known disease associated with PAD4 clinically, we established its efficacy in vivo. These results suggest that JBI-589 would be beneficial for both PAD4 and NET-associated pathological conditions.

Monoclonal Gammopathy of Thrombotic Significance

The current review provides an overview of the thrombotic risk observed in patients with MG who do not otherwise require treatment. We discuss clinical and biomarker studies that highlight the heterogenous hemostatic profile observed in these patients and how knowledge has evolved over the past 20 years. Biomarker studies suggest shared biologic features between multiple myeloma and monoclonal gammopathy of undetermined significance (MGUS), which involves both hypercoagulability and platelet activation. Hemostatic abnormalities identified in MGUS patients cannot be translated into clinical practice as they lack correlation to clinical events. The prothrombotic phenotype of MGUS patients has not been ascertained yet, but novel data on coagulation markers are promising. We also review rare conditions associated with the thrombogenic properties of the monoclonal protein that predispose to arterial, venous or microthrombotic events and demonstrate that the M-protein can be linked to clinically significant thrombotic events. Cryoglobulinemia, cryofibrinogenemia, cryo-crystaloglobulinemia and MG-related antiphospholipid syndrome are reviewed. We propose the new umbrella term "monoclonal gammopathy of thrombotic significance" (MGTS) to refer to significant, recurrent thrombotic events in patients with MGUS that provide a rationale for targeting the underlying plasma cell clone. Identifying MGUS patients at high risk for thrombotic events is currently a challenge.

Anti-citrullinated histone monoclonal antibody CIT-013, a dual action therapeutic for neutrophil extracellular trap-associated autoimmune diseases

Neutrophil extracellular traps (NETs) contribute to the pathophysiology of multiple inflammatory and autoimmune diseases. Targeting the NETosis pathway has demonstrated significant therapeutic potency in various disease models. Here, we describe a first-in-class monoclonal antibody (CIT-013) with high affinity for citrullinated histones H2A and H4, which inhibits NETosis and reduces tissue NET burden in vivo with significant anti-inflammatory consequences. We provide a detailed understanding of the epitope selectivity of CIT-013. Detection of CIT-013 epitopes in rheumatoid arthritis (RA) synovium provides evidence that RA is an autoimmune disease with excessive citrullinated NETs that can be targeted by CIT-013. We show that CIT-013 acts upon the final stage of NETosis, binding to its chromatin epitopes when plasma membrane integrity is compromised to prevent NET release. Bivalency of CIT-013 is necessary for NETosis inhibition. In addition, we show that CIT-013 binding to NETs and netting neutrophils enhance their phagocytosis by macrophages in an Fc-dependent manner. This is confirmed using a murine neutrophilic airway inflammation model where a mouse variant of CIT-013 reduced tissue NET burden with significant anti-inflammatory consequences. CIT-013's therapeutic activity provides new insights for the development of NET antagonists and indicates the importance of a new emerging therapy for NET-driven diseases with unmet therapeutic needs.

The emerging role of neutrophil extracellular traps in cancer: from lab to ward

Neutrophil extracellular traps (NETs) are web-like structures derived from neutrophils, which typically consist of DNA, released from the nucleus or mitochondria, and decorated with histones and granule proteins. They are well known as an important structure in innate immunity to eliminate pathogenic bacteria, similar to neutrophils. Initially, NETs are reported to take part in the progression of inflammatory diseases; now, they have also been implicated in the progression of sterile inflammation such as autoimmune disease, diabetes, and cancer. In this review, we will describe the recent studies which have investigated the role of NETs in the development of cancer, especially metastasis. We also prescribe the strategies for targeting NETs in the multiple cancer types, which suggest that NETs are a promising treatment for cancer patients.

Role of the PADI family in inflammatory autoimmune diseases and cancers: A systematic review

The peptidyl arginine deiminase (PADI) family is a calcium ion-dependent group of isozymes with sequence similarity that catalyze the citrullination of proteins. Histones can serve as the target substrate of PADI family isozymes, and therefore, the PADI family is involved in NETosis and the secretion of inflammatory cytokines. Thus, the PADI family is associated with the development of inflammatory autoimmune diseases and cancer, reproductive development, and other related diseases. In this review, we systematically discuss the role of the PADI family in the pathogenesis of various diseases based on studies from the past decade to provide a reference for future research.

CAR-T cell therapy in multiple myeloma: Current limitations and potential strategies

Over the last decade, the survival outcome of patients with multiple myeloma (MM) has been substantially improved with the emergence of novel therapeutic agents, such as proteasome inhibitors, immunomodulatory drugs, anti-CD38 monoclonal antibodies, selective inhibitors of nuclear export (SINEs), and T cell redirecting bispecific antibodies. However, MM remains an incurable neoplastic plasma cell disorder, and almost all MM patients inevitably relapse due to drug resistance. Encouragingly, B cell maturation antigen (BCMA)-targeted chimeric antigen receptor T (CAR-T) cell therapy has achieved impressive success in the treatment of relapsed/refractory (R/R) MM and brought new hopes for R/R MM patients in recent years. Due to antigen escape, the poor persistence of CAR-T cells, and the complicated tumor microenvironment, a significant population of MM patients still experience relapse after anti-BCMA CAR-T cell therapy. Additionally, the high manufacturing costs and time-consuming manufacturing processes caused by the personalized manufacturing procedures also limit the broad clinical application of CAR-T cell therapy. Therefore, in this review, we discuss current limitations of CAR-T cell therapy in MM, such as the resistance to CAR-T cell therapy and the limited accessibility of CAR-T cell therapy, and summarize some optimization strategies to overcome these challenges, including optimizing CAR structure, such as utilizing dual-targeted/multi-targeted CAR-T cells and armored CAR-T cells, optimizing manufacturing processes, combing CAR-T cell therapy with existing or emerging therapeutic approaches, and performing subsequent anti-myeloma therapy after CAR-T cell therapy as salvage therapy or maintenance/consolidation therapy.

The coming of age of neutrophil extracellular traps in thrombosis: Where are we now and where are we headed?

Thrombosis remains a major problem in our society, manifesting across multiple demographic groups and with high associated morbidity and mortality. Thrombus development is the result of a complex mechanism in which multiple cell types and soluble factors play a crucial role. One cell that has gained the most attention in recent years is the neutrophil. This key member of the innate immune system can form neutrophil extracellular traps (NETs) in response to activating stimuli in circulation. NETs form a scaffold for thrombus formation, both initiating the process and stabilizing the final product. As the first responders of the host immune system, neutrophils have the flexibility to recognize a variety of molecules and can quickly interact with a range of different cell types. This trait makes them sensitive to exogenous stimuli. NET formation in response to pathogens is well established, leading to immune-mediated thrombus formation or immunothrombosis. NETs can also be formed during sterile inflammation through the activation of neutrophils by fellow immune cells including platelets, or activated endothelium. In chronic inflammatory settings, NETs can ultimately promote the development of tissue fibrosis, with organ failure as an end-stage outcome. In this review, we discuss the different pathways through which neutrophils can be activated toward NET formation and how these processes can result in a shared outcome: thrombus formation. Finally, we evaluate these different interactions and mechanisms for their potential as therapeutic targets, with neutrophil-targeted therapies providing a future approach to treating thrombosis. In contrast to current practices, such treatment could result in reduced pathogenic blood clot formation without increasing the risk of bleeding.

Approach to Contemporary Risk Assessment, Prevention and Management of Thrombotic Complications in Multiple Myeloma

Multiple myeloma (MM) is associated with an increased risk of thrombotic complications, which remains substantial despite the implementation of thromboprophylaxis. The procoagulant state that characterizes the disease is multifactorial, and a greater understanding of the underlying pathophysiology is required to inform appropriate thrombosis prevention. Currently, there is a shift towards using direct oral anticoagulants (DOACs) in this setting; head-to-head comparisons in the context of controlled clinical trials between class agents are still missing. MM-specific VTE risk assessment scores have been developed to optimize management and minimize the associated mortality/morbidity. Their clinical utility remains to be evaluated. The value of adding biomarkers to clinical scores to optimize their performance and increase their discriminatory power is also under assessment.

Diverse Neutrophil Functions in Cancer and Promising Neutrophil-Based Cancer Therapies

Neutrophils represent the most abundant cell type of leukocytes in the human blood and have been considered a vital player in the innate immune system and the first line of defense against invading pathogens. Recently, several studies showed that neutrophils play an active role in the immune response during cancer development. They exhibited both pro-oncogenic and anti-tumor activities under the influence of various mediators in the tumor microenvironment. Neutrophils can be divided into several subpopulations, thus contradicting the traditional concept of neutrophils as a homogeneous population with a specific function in the innate immunity and opening new horizons for cancer therapy. Despite the promising achievements in this field, a full understanding of tumor-neutrophil interplay is currently lacking. In this review, we try to summarize the current view on neutrophil heterogeneity in cancer, discuss the different communication pathways between tumors and neutrophils, and focus on the implementation of these new findings to develop promising neutrophil-based cancer therapies.

Huang Qin Decoction inhibits the initiation of experimental colitis associated carcinogenesis by controlling the PAD4 dependent NETs

BACKGROUND

Colorectal cancer is associated with ulcerative colitis (UC). The infiltration of neutrophils is the main cause of DNA damage produced by inflammation in the intestinal epithelium. Under the action of peptidyl arginine deaminase 4 (PAD4), neutrophils dissociate chromatin and form neutrophil extracellular traps (NETs), which can aggravate tissue inflammation and encourage tumor development. Although Huang Qin Decoction (HQD) was found to be useful in treating UC and was used to gradually prevent and treat digestive tract cancers, the underlying reasons were unclear.

METHODS

To demonstrate HQD could inhibits the initiation of colitis associated carcinogenesis by controlling NETs related inflammation, we first performed an AOM/DSS-generated colitis-associated carcinogenesis model to assess the efficacy of HQD in reducing neutrophil infiltration and anti-tumor activity. Then, using network pharmacology research, we investigated the potential mechanisms underlying those medicinal effects, as demonstrated by the detection of NETs aggregation and PAD4 expression changes in the colon.

RESULTS

HQD substantially reduced the number of colon cancers and the expression of Ki67, restored the level of intestinal tight junction protein occludin and ZO-1, and relieved the intestinal inflammation caused by TNF-α, IL-1β. At the same time, it inhibited neutrophil infiltration in the colon and improved the immunosurveillance of CD8⁺T cells. The potential mechanisms of HQD intervention against UC and UC with neoplasia (UCN) were studied using network pharmacology, and 156 conjunct genes as well as numerous inflammation-related pathways were identified. Protein-protein interaction (PPI) analysis indicated that HQD inhibition of intestinal tumors might be related to the deactivation of PAD4, which was verified by the down-regulation of NETs, MPO-DNA complex levels, and PAD4 expression after HQD treatment.

CONCLUSION

Huang Qin Decoction inhibits the initiation of colitis associated carcinogenesis by controlling PAD4-dependent neutrophil extracellular traps.

Neutrophil extracellular traps and complications of liver transplantation

Many end-stage liver disease etiologies are attributed to robust inflammatory cell recruitment. Neutrophils play an important role in inflammatory infiltration and neutrophil phagocytosis, oxidative burst, and degranulation. It has also been suggested that neutrophils may release neutrophil extracellular traps (NETs) to kill pathogens. It has been proven that neutrophil infiltration within the liver contributes to an inflammatory microenvironment and immune cell activation. Growing evidence implies that NETs are involved in the progression of numerous complications of liver transplantation, including ischemia-reperfusion injury, acute rejection, thrombosis, and hepatocellular carcinoma recurrence. NETs are discussed in this comprehensive review, focusing on their effects on liver transplantation complications. Furthermore, we discuss NETs as potential targets for liver transplantation therapy.

Hotspots and trends in multiple myeloma bone diseases: A bibliometric visualization analysis

Objective: This study aims to explore the research hotspots and trends of multiple myeloma bone disease in the past 20 years by bibliometric visualization analysis.

Methods: With the Web of Science Core Collection database as the data source, the relevant publications of multiple myeloma bone disease from 2002 to 2021 are retrieved. These data are analyzed using software CiteSpace 5.8.R3 and Scimago Graphica 1.0.24, together with the Online Analysis Platform of Literature Metrology.

Results: A total of 6,168 published research papers, including 4668 articles and 1500 review papers, are included in this study. Generally speaking, annual publications and citations are on the rise, especially in recent 2 years. The majority of these papers are published in the United States, with Mayo Clinic being the greatest contributor. The most productive journal and author are Blood and Terpos E, respectively, while the most frequently co-cited reference, author and journal are Rajkumar et al., 2014, Lancet Oncol, Kyle RA and Blood, respectively. The major research subject categories are oncology and hematology. The “disease diagnosis”, “prognosis evaluation”, “pathogenesis”, “imaging technology” and “targeted therapy” are recent research frontiers. The burst keywords “transplantation”, “progression”, “activation”, “lenalidomide”, “flow cytometry”, “drug resistance”, “management” and “mesenchymal stem cell” reflect the latest research hotspots.

Conclusion: This study reveals the research hotspots and trends of multiple myeloma bone disease through bibliometric visualization analysis, and provides a valuable reference for further research.

Neutrophils: Musketeers against immunotherapy

Neutrophils, the most copious leukocytes in human blood, play a critical role in tumorigenesis, cancer progression, and immune suppression. Recently, neutrophils have attracted the attention of researchers, immunologists, and oncologists because of their potential role in orchestrating immune evasion in human diseases including cancer, which has led to a hot debate redefining the contribution of neutrophils in tumor progression and immunity. To make this debate fruitful, this review seeks to provide a recent update about the contribution of neutrophils in immune suppression and tumor progression. Here, we first described the molecular pathways through which neutrophils aid in cancer progression and orchestrate immune suppression/evasion. Later, we summarized the underlying molecular mechanisms of neutrophil-mediated therapy resistance and highlighted various approaches through which neutrophil antagonism may heighten the efficacy of the immune checkpoint blockade therapy. Finally, we have highlighted several unsolved questions and hope that answering these questions will provide a new avenue toward immunotherapy revolution.

Neutrophil extracellular traps: New players in cancer research

NETs are chromatin-derived webs extruded from neutrophils as a result of either infection or sterile stimulation using chemicals, cytokines, or microbes. In addition to the classical role that NETs play in innate immunity against infection and injuries, NETs have been implicated extensively in cancer progression, metastatic dissemination, and therapy resistance. The purpose of this review is to describe recent investigations into NETs and the roles they play in tumor biology and to explore their potential as therapeutic targets in cancer treatment.

A Pilot Study on Peptidylarginine Deiminases and Protein Deimination in Animal Cancers across Vertebrate Species

PADs are a group of calcium-dependent enzymes that play key roles in inflammatory pathologies and have diverse roles in cancers. PADs cause irreversible post-translational modification of arginine to citrulline, leading to changes in protein function in different cellular compartments. PAD isozyme diversity differs throughout phylogeny in chordates, with five PAD isozymes in mammals, three in birds, and one in fish. While the roles for PADs in various human cancers are mounting (both in regards to cancer progression and epigenetic regulation), investigations into animal cancers are scarce. The current pilot-study therefore aimed at assessing PAD isozymes in a range of animal cancers across the phylogeny tree. In addition, the tissue samples were assessed for total protein deimination and histone H3 deimination (CitH3), which is strongly associated with human cancers and also indicative of gene regulatory changes and neutrophil extracellular trap formation (NETosis). Cancers were selected from a range of vertebrate species: horse, cow, reindeer, sheep, pig, dog, cat, rabbit, mink, hamster, parrot, and duck. The cancers chosen included lymphoma, kidney, lung, testicular, neuroendocrine, anaplastic, papilloma, and granulosa cell tumour. Immunohistochemical analysis revealed that CitH3 was strongly detected in all of the cancers assessed, while pan-deimination detection was overall low. Both PAD2 and PAD3 were the most predominantly expressed PADs across all of the cancers assessed, while PAD1, PAD4, and PAD6 were overall expressed at lower, albeit varying, levels. The findings from this pilot study provide novel insights into PAD-mediated roles in different cancers across a range of vertebrate species and may aid in the understanding of cancer heterogeneity and cancer evolution.

Recent progress in the mechanistic understanding of NET formation in neutrophils

Neutrophils are the most abundant circulating white blood cells and one of the major cell types of the innate immune system. Neutrophil extracellular traps (NETs) are a result of the extracellular release of nuclear chromatin from the ruptured nuclear envelope and plasma membrane. The externalized chromatin is an ancient defense weapon for animals to entrap and kill microorganisms in the extracellular milieu, thus protecting animals ranging from lower invertebrates to higher vertebrates. Although the externalized chromatin has the advantage of acting as anti-infective to protect against infections, extracellular chromatin might be problematic in higher vertebrate animals as they have an adaptive immune system that can trigger further immune or autoimmune responses. NETs and their associated nuclear and/or cytoplasmic components may induce sterile inflammation, immune, and autoimmune responses, leading to various human diseases. Though important in human pathophysiology, the cellular and molecular mechanisms of NET formation (also called NETosis) are not well understood. Given that nuclear chromatin forms the backbone of NETs, the nucleus is the root of the nuclear DNA extracellular traps. Thus, nuclear chromatin decondensation, along with the rupture of nuclear envelope and plasma membrane, is required for nuclear chromatin extracellular release and NET formation. So far, most of the literature focuses on certain signaling pathways, which are involved in NET formation but without explanation of cellular events and morphological changes described above. Here, we have summarized emerging evidence and discuss new mechanistic understanding, with our perspectives, in NET formation in neutrophils.

The Significance of Neutrophil Extracellular Traps in Colorectal Cancer and Beyond: From Bench to Bedside

Neutrophil extracellular traps (NETs), products of neutrophil death when exposed to certain stimuli, were first proposed as a type of response to bacterial infection in infectious diseases. Since then, extensive studies have discovered its involvement in other non-infectious inflammatory diseases including thromboembolism, autoimmune diseases, and cancer. Colorectal cancer (CRC) is one of the most common malignancies in the world. NET formation is closely associated with tumorigenesis, progression, and metastasis in CRC. Therefore, the application of NETs in clinical practice as diagnostic biomarkers, therapeutic targets, and prognostic predictors has a promising prospect. In addition, therapeutics targeting NETs are significantly efficient in halting tumor progression in preclinical cancer models, which further indicates its potential clinical utility in cancer treatment. This review focuses on the stimuli of NETosis, its pro-tumorigenic activity, and prospective clinical utility primarily in but not limited to CRC.

Citrullination of glucokinase is linked to autoimmune diabetes

Inflammation, including reactive oxygen species and inflammatory cytokines in tissues amplify various post-translational modifications of self-proteins. A number of post-translational modifications have been identified as autoimmune biomarkers in the initiation and progression of Type 1 diabetes. Here we show the citrullination of pancreatic glucokinase as a result of inflammation, triggering autoimmunity and affecting glucokinase biological functions. Glucokinase is expressed in hepatocytes to regulate glycogen synthesis, and in pancreatic beta cells as a glucose sensor to initiate glycolysis and insulin signaling. We identify autoantibodies and autoreactive CD4+ T cells to glucokinase epitopes in the circulation of Type 1 diabetes patients and NOD mice. Finally, citrullination alters glucokinase biologic activity and suppresses glucose-stimulated insulin secretion. Our study define glucokinase as a Type 1 diabetes biomarker, providing new insights of how inflammation drives post-translational modifications to create both neoautoantigens and affect beta cell metabolism.