Neutrophil Extracellular Trap Induced Dendritic Cell Activation Leads to Th1 Polarization in Type 1 Diabetes

Identification of Molecular Subtype and Prognostic Signature for Prostate Adenocarcinoma based on Neutrophil Extracellular Traps

Background: Prostate adenocarcinoma (PRAD) is one of the most common cancers in male. Increasing evidences pointed out that Neutrophil Extracellular Traps (NETs) play an important role in tumor angiogenesis, tumor metastasis and drug resistance. However, limited systematic studies regarding the role of NETs in PRAD have been performed. Identification of biomarkers based on NETs might facilitate risk stratification which help optimizing the clinical strategies. Methods: NETs-related genes with differential expressions were identified between PRAD and adjacent normal tissues in TCGA-PRAD dataset. Consensus cluster analysis was performed to determine the PRAD subtypes based on the different-expressed NETs-related genes. The difference of pathway enrichment, infiltrating immune cell and genomic mutation were also evaluated between subtypes. LASSO cox regression analysis was conducted to construct a NETs-related prognostic signature. Result: We identified 19 NETs related genes with differential expressions between PRAD and adjacent normal tissue in TCGA-PRAD dataset. Two significant subtypes were identified based on these 19 genes by consensus cluster analysis, namely subtype 1 and subtype 2. Significant differences in prognosis, immune infiltration and tumor mutation burden were observed in subtypes. LASSO Cox regression analysis identified a NETs-associated prognostic signature including 13 genes, and this signature had a good performance in predicting the progression-free survival of PRAD patients. Further integrated analysis indicated that MMP9 mostly expressed in Mono/Macrophage cells might play a role in regulating NETs formation via neutrophil activation in PRAD. Conclusion: To sum up, the current study identified two NETs-related molecular subtypes and based on which constructed a prognostic signature for PRAD.

The Role and Mechanism of Metformin in Inflammatory Diseases

Metformin is a classical drug used to treat type 2 diabetes. With the development of research on metformin, it has been found that metformin also has several advantages aside from its hypoglycemic effect, such as anti-inflammatory, anti-aging, anti-cancer, improving intestinal flora, and other effects. The prevention of inflammation is critical because chronic inflammation is associated with numerous diseases of considerable public health. Therefore, there has been growing interest in the role of metformin in treating various inflammatory conditions. However, the precise anti-inflammatory mechanisms of metformin were inconsistent in the reported studies. Thus, this review aims to summarize various currently known possible mechanisms of metformin involved in inflammatory diseases and provide references for the clinical application of metformin.

Neutrophils in STAT1 Gain-Of-Function Have a Pro-inflammatory Signature Which Is Not Rescued by JAK Inhibition

STAT1 gain-of-function (GOF) mutations cause an inborn error of immunity with diverse phenotype ranging from chronic mucocutaneous candidiasis (CMC) to various non-infectious manifestations, the most precarious of which are autoimmunity and vascular complications. The pathogenesis centers around Th17 failure but is far from being understood. We hypothesized that neutrophils, whose functions have not been explored in the context of STAT1 GOF CMC yet, might be involved in the associated immunodysregulatory and vascular pathology. In a cohort of ten patients, we demonstrate that STAT1 GOF human ex-vivo peripheral blood neutrophils are immature and highly activated; have strong propensity for degranulation, NETosis, and platelet-neutrophil aggregation; and display marked inflammatory bias. STAT1 GOF neutrophils exhibit increased basal STAT1 phosphorylation and expression of IFN stimulated genes, but contrary to other immune cells, STAT1 GOF neutrophils do not display hyperphosphorylation of STAT1 molecule upon stimulation with IFNs. The patient treatment with JAKinib ruxolitinib does not ameliorate the observed neutrophil aberrations. To our knowledge, this is the first work describing features of peripheral neutrophils in STAT1 GOF CMC. The presented data suggest that neutrophils may contribute to the immune pathophysiology of the STAT1 GOF CMC.

Role of neutrophil extracellular trap and immune infiltration in atherosclerotic plaque instability: Novel insight from bioinformatics analysis and machine learning

The instability of atherosclerotic plaques increases the risk of acute coronary syndrome. Neutrophil extracellular traps (NETs), mesh-like complexes consisting of extracellular DNA adorned with various protein substances, have been recently discovered to play an essential role in atherosclerotic plaque formation and development. This study aimed to investigate novel diagnostic biomarkers that can identify unstable plaques for early distinction and prevention of plaque erosion or disruption. Differential expression analysis was used to identify the differentially expressed NET-related genes, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed. We filtered the characteristic genes using machine learning and estimated diagnostic efficacy using receiver operating characteristic curves. Immune infiltration was detected using single-sample gene set enrichment analysis and the biological signaling pathways involved in characteristic genes utilizing gene set enrichment analysis were explored. Finally, miRNAs- and transcription factors-target genes networks were established. We identified 8 differentially expressed NET-related genes primarily involved in immune-related pathways. Four were identified as capable of distinguishing unstable plaques. More immune cells infiltrated unstable plaques than stable plaques, and these cells were predominantly positively related to characteristic genes. These 4 diagnostic genes are involved in immune responses and the modulation of smooth muscle contractility. Several miRNAs and transcription factors were predicted as upstream regulatory factors, providing further information on the identification and prevention of atherosclerotic plaques rupture. We identified several promising NET-related genes (AQP9, C5AR1, FPR3, and SIGLEC9) and immune cell subsets that may identify unstable atherosclerotic plaques at an early stage and prevent various complications of plaque disruption.

NET-targeted therapy: effects, limitations, and potential strategies to enhance treatment efficacy

Neutrophil extracellular traps (NETs) are complex structures released by activated neutrophils during inflammatory responses. Due to their unique potential for causing tissue damage and modulating immune responses, there is increasing interest in studying these structures as potential targets for the treatment of infectious diseases, autoimmune diseases, and cancer. However, therapeutic targeting of NETs might trigger deleterious effects that may limit treatment efficacy. NET disruption may increase the microbial load in infection; in autoimmunity, NET targeting might impair peripheral tolerance, but it might reduce adaptive immune responses in cancer. In this review, we explore the therapeutic and deleterious effects of NET-targeted therapy while shedding light on novel strategies to overcome treatment-related limitations and enhance treatment efficacy.

A secreted sirtuin from Campylobacter jejuni contributes to neutrophil activation and intestinal inflammation during infection

Histone modifications control numerous processes in eukaryotes, including inflammation. Some bacterial pathogens alter the activity or expression of host-derived factors, including sirtuins, to modify histones and induce responses that promote infection. In this study, we identified a deacetylase encoded by Campylobacter jejuni which has sirtuin activities and contributes to activation of human neutrophils by the pathogen. This sirtuin is secreted from the bacterium into neutrophils, where it associates with and deacetylates host histones to promote neutrophil activation and extracellular trap production. Using the murine model of campylobacteriosis, we found that a mutant of this bacterial sirtuin efficiently colonized the gastrointestinal tract but was unable to induce cytokine production, gastrointestinal inflammation, and tissue pathology. In conclusion, these results suggest that secreted bacterial sirtuins represent a previously unreported class of bacterial effector and that bacterial-mediated modification of host histones is responsible for the inflammation and pathology that occurs during campylobacteriosis.

Neutrophil extracellular traps (NET): not only antimicrobial but also modulators of innate and adaptive immunities in inflammatory autoimmune diseases

Polymorphonuclear neutrophils (PMN) represent one of the first lines of defence against invading pathogens and are the most abundant leucocytes in the circulation. Generally described as pro-inflammatory cells, recent data suggest that PMN also have immunomodulatory capacities. In response to certain stimuli, activated PMN expel neutrophil extracellular traps (NET), structures made of DNA and associated proteins. Although originally described as an innate immune mechanism fighting bacterial infection, NET formation (or probably rather an excess of NET together with impaired clearance of NET) may be deleterious. Indeed, NET have been implicated in the development of several inflammatory and autoimmune diseases as rheumatoid arthritis or systemic lupus erythematosus, as well as fibrosis or cancer. They have been suggested as a source of (neo)autoantigens or regulatory proteins like proteases or to act as a physical barrier. Different mechanisms of NET formation have been described, leading to PMN death or not, depending on the stimulus. Interestingly, NET may be both pro-inflammatory and anti-inflammatory and this probably partly depends on the mechanism, and thus the stimuli, triggering NET formation. Within this review, we will describe the pro-inflammatory and anti-inflammatory activities of NET and especially how NET may modulate immune responses.

Neutrophil extracellular traps in acute coronary syndrome

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

NET Proteome in Established Type 1 Diabetes Is Enriched in Metabolic Proteins

BACKGROUND AND AIMS

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by a T-cell-mediated destruction of the pancreatic insulin-producing beta cells. A growing body of evidence suggests that abnormalities in neutrophils and neutrophil extracellular trap (NET) formation (NETosis) are associated with T1D pathophysiology. However, little information is available on whether these changes are primary neutrophil defects or related to the environmental signals encountered during active disease.

METHODS

In the present work, the NET proteome (NETome) of phorbol 12-myristate 13-acetate (PMA)- and ionomycin-stimulated neutrophils from people with established T1D compared to healthy controls (HC) was studied by proteomic analysis.

RESULTS

Levels of NETosis, in addition to plasma levels of pro-inflammatory cytokines and NET markers, were comparable between T1D and HC subjects. However, the T1D NETome was distinct from that of HC in response to both stimuli. Quantitative analysis revealed that the T1D NETome was enriched in proteins belonging to metabolic pathways (i.e., phosphoglycerate kinase, glyceraldehyde-3-phosphate dehydrogenase, and UTP-glucose-1-phosphate uridylyltransferase). Complementary metabolic profiling revealed that the rate of extracellular acidification, an approximate measure for glycolysis, and mitochondrial respiration were similar between T1D and HC neutrophils in response to both stimuli.

CONCLUSION

The NETome of people with established T1D was enriched in metabolic proteins without an apparent alteration in the bio-energetic profile or dysregulated NETosis. This may reflect an adaptation mechanism employed by activated T1D neutrophils to avoid impaired glycolysis and consequently excessive or suboptimal NETosis, pivotal in innate immune defence and the resolution of inflammation.

The Association Between Insulin Use and Asthma: An Epidemiological Observational Analysis and Mendelian Randomization Study

BACKGROUND

Asthma is a common respiratory disease caused by genetic and environmental factors, but the contribution of insulin use to the risk of asthma remains unclear. This study aimed to investigate the association between insulin use and asthma in a large population-based cohort, and further explore their causal relationship by Mendelian randomization (MR) analysis.

METHODS

An epidemiological study including 85,887 participants from the National Health and Nutrition Examination Survey (NHANES) 2001-2018 was performed to evaluate the association between insulin use and asthma. Based on the inverse-variance weighted approach, MR analysis were conducted to estimate the causal effect of insulin use on asthma from the UKB and FinnGen datasets, respectively.

RESULTS

In the NHANES cohort, we found that insulin use was associated with an increased risk of asthma [odd ratio (OR) 1.38; 95% CI 1.16-1.64; p < 0.001]. For the MR analysis, we found a causal relationship between insulin use and a higher risk of asthma in both Finn (OR 1.10; p < 0.001) and UK Biobank cohorts (OR 1.18; p < 0.001). Meanwhile, there was no causal association between diabetes and asthma. After multivariable adjustment for diabetes in UKB cohort, the insulin use remained significantly associated with an increased risk of asthma (OR 1.17, p < 0.001).

CONCLUSIONS

An association between insulin use and an increased risk of asthma was found via the real-world data from the NHANES. In addition, the current study identified a causal effect and provided a genetic evidence of insulin use and asthma. More studies are needed to elucidate the mechanisms underlying the association between insulin use and asthma.

Neutrophil Heterogeneity and its Roles in the Inflammatory Network after Ischemic Stroke

As the first peripheral immune cells to enter the brain after ischemic stroke, neutrophils are important participants in stroke-related neuroinflammation. Neutrophils are quickly mobilized from the periphery in response to a stroke episode and cross the blood-brain barrier to reach the ischemic brain parenchyma. This process involves the mobilization and activation of neutrophils from peripheral immune organs (including the bone marrow and spleen), their chemotaxis in the peripheral blood, and their infiltration into the brain parenchyma (including disruption of the blood-brain barrier, inflammatory effects on brain tissue, and interactions with other immune cell types). In the past, it was believed that neutrophils aggravated brain injuries through the massive release of proteases, reactive oxygen species, pro-inflammatory factors, and extracellular structures known as neutrophil extracellular traps (NETs). With the failure of early clinical trials targeting neutrophils and uncovering their underlying heterogeneity, our view of their role in ischemic stroke has become more complex and multifaceted. As neutrophils can be divided into N1 and N2 phenotypes in tumors, neutrophils have also been found to have similar phenotypes after ischemic stroke, and play different roles in the development and prognosis of ischemic stroke. N1 neutrophils are dominant during the acute phase of stroke (within three days) and are responsible for the damage to neural structures via the aforementioned mechanisms. However, the proportion of N2 neutrophils gradually increases in later phases, and this has a beneficial effect through the release of anti-inflammatory factors and other neuroprotective mediators. Moreover, the N1 and N2 phenotypes are highly plastic and can be transformed into each other under certain conditions. The pronounced differences in their function and their high degree of plasticity make these neutrophil subpopulations promising targets for the treatment of ischemic stroke.

Aberrant tolerogenic functions and proinflammatory skew of dendritic cells in STAT1 gain-of-function patients may contribute to autoimmunity and fungal susceptibility

STAT1 gain-of-function (GOF) mutations underlie an inborn error of immunity hallmarked by chronic mucocutaneous candidiasis (CMC). Beyond the fungal susceptibility, attributed to Th17 failure, over half of the reported patients suffer from autoimmune manifestations, mechanism of which has not been explained yet. We hypothesized that the STAT1 mutations would affect dendritic cells' (DCs) properties and alter their inflammatory and tolerogenic functions. To test the hypothesis, we generated monocyte-derived DCs (moDCs) and tolerogenic DCs (tDCs). Functional and signaling studies, co-culture experiments and RNA sequencing demonstrated that STAT1 GOF DCs were profoundly altered in their phenotype and functions, characterized by loss of tolerogenic functions, proinflammatory skew and decreased capacity to induce Th17. Cytokine signaling, autophagy and metabolic processes were identified as the most prominently altered cellular processes. The results suggest that DCs are directly involved in STAT1 GOF-associated immune pathology, possibly contributing to both autoimmune manifestations and the failure of antifungal defense.

No NETs no TIME: Crosstalk between neutrophil extracellular traps and the tumor immune microenvironment

The tumor immune microenvironment (TIME) controls tumorigenesis. Neutrophils are important components of TIME and control tumor progression and therapy resistance. Neutrophil extracellular traps (NETs) ejected by activated neutrophils are net-like structures composed of decondensed extracellular chromatin filaments decorated with a plethora of granules as well as cytoplasmic proteins. Many of these harbour post translational modifications. Cancer cells reportedly trigger NET formation, and conversely, NETs alter the TIME and promote tumor cell proliferation and migration. The specific interactions between NETs and TIME and the respective effects on tumor progression are still elusive. In certain tumors, a CD4⁺ T helper (Th) 2 cell-associated TIME induces NETs and exerts immunosuppressive functions via programmed death 1 (PD-1)/PD-L1, both associated with poorer prognosis. In other cases, NETs induce the proliferation of Th1 cells, associated with an improved prognosis in cancer. In addition, NETs can drive macrophage polarization and often rely on macrophages to promote cancer cell invasion and metastasis. In turn, macrophages can swiftly clear NETs in an immunologically silent manner. The aim of this review is to summarize the knowledge about the mutual interaction between NETs and TIME and its impact on tumor growth and therapy.

Role of neutrophil extracellular traps in inflammatory evolution in severe acute pancreatitis

ABSTRACT

Severe acute pancreatitis (SAP) is a life-threatening acute abdominal disease with two peaks of death: the first in the early stage, characterized by systemic inflammatory response-associated organ failure; and the second in the late stage, characterized by infectious complications. Neutrophils are the main immune cells participating in the whole process of SAP. In addition to the traditional recognition of neutrophils as the origination of chemokine and cytokine cascades or phagocytosis and degranulation of pathogens, neutrophil extracellular traps (NETs) also play an important roles in inflammatory reactions. We reviewed the role of NETs in the occurrence and development of SAP and its fatal complications, including multiple organs injury, infected pancreatic necrosis, and thrombosis. This review provides novel insights into the involvement of NETs throughout the entire process of SAP, showing that targeting NETs might be a promising strategy in SAP treatment. However, precision therapeutic options targeting NETs in different situations require further investigation.

Identification of renal ischemia reperfusion injury subtypes and predictive strategies for delayed graft function and graft survival based on neutrophil extracellular trap-related genes

Background

Ischemia reperfusion injury (IRI) is an inevitable process in renal transplantation, which is closely related to serious postoperative complications such as delayed graft function (DGF), acute rejection and graft failure. Neutrophil extracellular traps (NETs) are extracellular DNA structures decorated with various protein substances released by neutrophils under strong signal stimulation. Recently, NETs have been found to play an important role in the process of IRI. This study aimed to comprehensively analyze the expression landscape of NET-related genes (NRGs) during IRI, identify clusters with different degrees of IRI and construct robust DGF and long-term graft survival predictive strategies.

Methods

The microarray and RNA-seq datasets were obtained from the GEO database. Differentially expressed NRGs (DE-NRGs) were identified by the differential expression analysis, and the NMF algorithm was used to conduct a cluster analysis of IRI samples. Machine learning algorithms were performed to screen DGF-related hub NRGs, and DGF and long-term graft survival predictive strategies were constructed based on these hub NRGs. Finally, we verified the expression of Cxcl1 and its effect on IRI and NETs generation in the mouse IRI model.

Results

This study revealed two IRI clusters (C1 and C2 clusters) with different molecular features and clinical characteristics. Cluster C1 was characterized by active metabolism, mild inflammation and lower incidence of DGF, while Cluster C2 was inflammation activated subtype with a higher incidence of DGF. Besides, based on DGF-related hub NRGs, we successfully constructed robust DGF and long-term graft survival predictive strategies. The mouse renal IRI model verified that Cxcl1 was significantly upregulated in renal tissues after IRI, and using a CXCL8/CXCL1 inhibitor could significantly improve renal function, alleviate renal tubular necrosis, tissue inflammatory response, and NET formation.

Conclusion

This study identified two distinct IRI clusters based on DE-NRGs and constructed robust prediction methods for DGF and graft survival, which can provide references for early prevention and individualized treatment of various postoperative complications after renal transplantation.

Neutrophil extracellular traps facilitate cancer metastasis: cellular mechanisms and therapeutic strategies

Background

The formation of neutrophil extracellular traps (NETs) was initially discovered as a novel immune response against pathogens. Recent studies have also suggested that NETs play an important role in tumor progression. This review summarizes the cellular mechanisms by which NETs promote distant metastasis and discusses the possible clinical applications targeting NETs.

Method

The relevant literature from PubMed and Google Scholar (2001–2021) have been reviewed for this article.

Results

The presence of NETs has been detected in various primary tumors and metastatic sites. NET-associated interactions have been observed throughout the different stages of metastasis, including initial tumor cell detachment, intravasation and extravasation, the survival of circulating tumor cells, the settlement and the growth of metastatic tumor cells. Several in vitro and in vivo studies proved that inhibiting NET formation resulted in anti-cancer effects. The biosafety and efficacy of some NET inhibitors have also been demonstrated in early phase clinical trials.

Conclusions

Considering the role of NETs in tumor progression, NETs could be a promising diagnostic and therapeutic target for cancer management. However, current evidence is mostly derived from experimental models and as such more clinical studies are still needed to verify the clinical significance of NETs in oncological settings.

Increased histone citrullination in juvenile idiopathic arthritis

Objective

Posttranslational modifications (PTMs) of proteins are crucial for regulating various biological processes. However, protein alteration via PTMs, and consequently, the creation of new epitopes, can induce abnormal autoimmune responses in predisposed individuals. Immunopathogenesis of several rheumatic diseases, including the most common childhood form, juvenile idiopathic arthritis (JIA), is associated with the generation of autoantibodies against such modified proteins. Dysregulated generation of neutrophil extracellular traps (NETs) can be a source of post-translationally altered proteins. Thus, we investigated the role of PTMs and the presence of NET-associated markers in JIA patients.

Methods

We recruited 30 pediatric patients with JIA (20 with active disease and 10 in remission) and 30 healthy donors. The serum concentrations of citrullinated histone H3 (citH3), peptidyl arginine deiminases (PADs), and NET-related products were detected using ELISA, and the number of citH3+ neutrophils was assessed using flow cytometry.

Results

The serum levels of citH3 and PADs were higher in active as well as in remission JIA patients than in healthy donors. Similarly, the number of citH3+ neutrophils was higher in the peripheral blood of patients with JIA, implying an enhanced process of NETosis. This was effectively reflected by elevated serum levels of NET-associated products, such as neutrophil elastase, LL37, and cell-free DNA-histone complexes. Additionally, 16.7% of active JIA patients were seropositive for carbamylated autoantibodies, the levels of which declined sharply after initiation of anti-TNFα therapy.

Conclusion

Collectively, our data suggest that the accelerated process of NETosis and PTMs in JIA may result in the generation of anti-citrullinated/carbamylated autoantibodies against various epitopes later in life, which could be prevented by effectively regulating inflammation using immune therapy.

Host-microbiota interactions shaping T-cell response and tolerance in type 1 diabetes

Type-1 Diabetes (T1D) is a complex polygenic autoimmune disorder involving T-cell driven beta-cell destruction leading to hyperglycemia. There is no cure for T1D and patients rely on exogenous insulin administration for disease management. T1D is associated with specific disease susceptible alleles. However, the predisposition to disease development is not solely predicted by them. This is best exemplified by the observation that a monozygotic twin has just a 35% chance of developing T1D after their twin’s diagnosis. This makes a strong case for environmental triggers playing an important role in T1D incidence. Multiple studies indicate that commensal gut microbiota and environmental factors that alter their composition might exacerbate or protect against T1D onset. In this review, we discuss recent literature highlighting microbial species associated with T1D. We explore mechanistic studies which propose how some of these microbial species can modulate adaptive immune responses in T1D, with an emphasis on T-cell responses. We cover topics ranging from gut-thymus and gut-pancreas communication, microbial regulation of peripheral tolerance, to molecular mimicry of islet antigens by microbial peptides. In light of the accumulating evidence on commensal influences in neonatal thymocyte development, we also speculate on the link between molecular mimicry and thymic selection in the context of T1D pathogenesis. Finally, we explore how these observations could inform future therapeutic approaches in this disease.

LL-37, a Multi-Faceted Amphipathic Peptide Involved in NETosis

Innate immunity responds to infections and inflammatory stimuli through a carefully choreographed set of interactions between cells, stimuli and their specific receptors. Of particular importance are endogenous peptides, which assume roles as defensins or alarmins, growth factors or wound repair inducers. LL-37, a proteolytic fragment of cathelicidin, fulfills the roles of a defensin by inserting into the membranes of bacterial pathogens, functions as alarmin in stimulating chemotaxis of innate immune cells, and alters the structure and efficacy of various cytokines. Here, we draw attention to the direct effect of LL-37 on neutrophils and the release of extracellular traps (NETs), as NETs have been established as mediators of immune defense against pathogens but also as important contributors to chronic disease and tissue pathogenesis. We propose a specific structural basis for LL-37 function, in part by highlighting the structural flexibility of LL-37 and its ability to adapt to distinct microenvironments and interacting counterparts.

The Contribution of Neutrophils and NETs to the Development of Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease resulting from the destruction of insulin-producing beta cells in pancreatic islets. T lymphocytes are the claimed pathogenic effectors but abnormalities of other immune cell types, including neutrophils, also characterize T1D development. During human T1D natural history, neutrophils are reduced in the circulation, while accumulate in the pancreas where release of neutrophil extracellular traps (NETs), or NETosis, is manifest. Recent-onset T1D patients also demonstrate activated circulating neutrophils, associated with a unique neutrophil gene signature. Neutrophils can bind to platelets, leading to the formation of platelet-neutrophil aggregates (PNAs). PNAs increase in the circulation during the development of human T1D and provide a mechanism for neutrophil activation and mobilization/recruitment to the pancreas. In non-obese diabetic or NOD mice, T1D autoimmunity is accompanied by dynamic changes in neutrophil numbers, activation state, PNAs and/or NETosis/NET proteins in the circulation, pancreas and/or islets. Such properties differ between stages of T1D disease and underpin potentially indirect and direct impacts of the innate immune system in T1D pathogenesis. Supporting the potential for a pathogenic role in T1D, NETs and extracellular histones can directly damage isolated islets in vitro, a toxicity that can be prevented by small polyanions. In human T1D, NET-related damage can target the whole pancreas, including both the endocrine and exocrine components, and contribute to beta cell destruction, providing evidence for a neutrophil-associated T1D endotype. Future intervention in T1D could therefore benefit from combined strategies targeting T cells and accessory destructive elements of activated neutrophils.

Neutrophils Actively Contribute to Obesity-Associated Inflammation and Pathological Complications

Obesity is characterized by an increase in body weight associated with an exaggerated enlargement of the adipose tissue. Obesity has serious negative effects because it is associated with multiple pathological complications such as type 2 diabetes mellitus, cardiovascular diseases, cancer, and COVID-19. Nowadays, 39% of the world population is obese or overweight, making obesity the 21st century epidemic. Obesity is also characterized by a mild, chronic, systemic inflammation. Accumulation of fat in adipose tissue causes stress and malfunction of adipocytes, which then initiate inflammation. Next, adipose tissue is infiltrated by cells of the innate immune system. Recently, it has become evident that neutrophils, the most abundant leukocytes in blood, are the first immune cells infiltrating the adipose tissue. Neutrophils then get activated and release inflammatory factors that recruit macrophages and other immune cells. These immune cells, in turn, perpetuate the inflammation state by producing cytokines and chemokines that can reach other parts of the body, creating a systemic inflammatory condition. In this review, we described the recent findings on the role of neutrophils during obesity and the initiation of inflammation. In addition, we discuss the involvement of neutrophils in the generation of obesity-related complications using diabetes as a prime example.

Extracellular DNA Traps: Origin, Function and Implications for Anti-Cancer Therapies

Extracellular DNA may serve as marker in liquid biopsies to determine individual diagnosis and prognosis in cancer patients. Cell death or active release from various cell types, including immune cells can result in the release of DNA into the extracellular milieu. Neutrophils are important components of the innate immune system, controlling pathogens through phagocytosis and/or the release of neutrophil extracellular traps (NETs). NETs also promote tumor progression and metastasis, by modulating angiogenesis, anti-tumor immunity, blood clotting and inflammation and providing a supportive niche for metastasizing cancer cells. Besides neutrophils, other immune cells such as eosinophils, dendritic cells, monocytes/macrophages, mast cells, basophils and lymphocytes can also form extracellular traps (ETs) during cancer progression, indicating possible multiple origins of extracellular DNA in cancer. In this review, we summarize the pathomechanisms of ET formation generated by different cell types, and analyze these processes in the context of cancer. We also critically discuss potential ET-inhibiting agents, which may open new therapeutic strategies for cancer prevention and treatment.

Identification of miRNA-mRNA-TF regulatory networks in peripheral blood mononuclear cells of type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is a T lymphocyte-mediated and B lymphocyte-assisted autoimmune disease. We aimed to identify abnormally expressed genes in peripheral blood mononuclear cells (PBMCs) of T1D and explore their possible molecular regulatory network.

METHODS

Expression datasets were downloaded from the Gene Expression Omnibus (GEO) database. Then, the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEmiRNAs) were identified, and functional enrichment and immune cell infiltration analysis were performed. The starBase, miRTarBase, TarBase, JASPAR, ENCODE, and TRRUST databases constructed the miRNA-mRNA-TF regulatory network. The ROC curves were plotted to evaluate the sensitivity and specificity of miRNAs and mRNAs.

RESULT

A total of 216 DEGs directly or indirectly related to type I diabetes mellitus, natural killer cell-mediated cytotoxicity, Th1, and Th2 cell differentiation, and the IL-17 and TNF signaling pathways were obtained. The miRNA-mRNA-TF network indicates that miR-320a and SOX5 are the only miRNAs and TFs that both target ADM and RRAGD. The ROC curves showed that ADM (0.9375), RRAGD (0.8958), and hsa-mir-320a (0.9417) had high accuracy in T1D diagnosis.

CONCLUSION

The constructed regulatory networks, including miR-320a/ADM/SOX5 and miR-320a/RRAGD/SOX5, may provide new insight into the mechanisms of development and progression in T1D.

NETosis in Long-Term Type 1 Diabetes Mellitus and Its Link to Coronary Artery Disease

Background

Neutrophil extracellular traps NETs have been linked to glucose and the pathogenesis of type 1 diabetes mellitus (T1DM). NETs also play a role in vascular inflammation and the development of coronary artery disease (CAD). The role of NETs in CAD progression in patients with long-term T1DM is unclear. We aimed to 1) investigate whether levels of circulating NETs markers were elevated in long-term T1DM subjects compared to controls, and 2) explore whether levels of NETs were related to the presence of CAD.

Material and Methods

102 patients with > 45 years of T1DM and 75 age-matched controls were enrolled in a cross-sectional study. Median age was 62 years. Computed tomography coronary angiography (CTCA) was performed in 148 subjects without established coronary heart disease. For the current study, CAD was defined as a coronary artery stenosis >50%. Double-stranded deoxyribonucleic acid (dsDNA) was measured by a nucleic acid stain, myeloperoxidase-DNA (MPO-DNA), citrullinated histone 3 (H3Cit) and peptidylarginine deiminase 4 (PAD4) by ELISAs, while gene expression of PAD4 was measured in leukocytes from PAXgene tubes.

Results

Circulating MPO-DNA levels were significantly lower in patients with T1DM than in controls (0.17 vs 0.29 OD, p<0.001), while dsDNA, H3Cit, PAD4 and gene expression of PAD4 did not differ with respect to the presence of T1DM. There were no significant associations between NETs markers and HbA1c in the T1DM group. None of the NETs markers differed according to the presence of CAD in patients with T1DM. While all circulating NETs markers correlated significantly with circulating neutrophils in the control group (r=0.292-393, p<0.014), only H3Cit and PAD4 correlated with neutrophils in the T1DM group (r= 0.330-0.449, p ≤ 0.001).

Conclusions

In this cross-sectional study of patients with long-term T1DM and age-matched controls, circulating NETs levels were not consistently associated with the presence of T1DM or glycemic status, and did not differ according to the presence of CAD in patients with T1DM. Our results entail the possibility of altered neutrophil function and reduced NETosis in T1DM. This warrants further investigation.

Neutrophil Extracellular Traps Caused by Gut Leakage Trigger the Autoimmune Response in Nonobese Diabetic Mice

Increased formation of neutrophil extracellular traps (NETs) is associated with gut leakage in type 1 diabetes (T1D). To explore the mechanism of how enteropathy exacerbated by NETs triggers pancreatic autoimmunity in T1D, we carried out a correlation analysis for NET formation with gut barrier functions and autoimmunity in nonobese diabetic (NOD) mice. Inducing chronic colitis or knocking out of peptidyl arginine deiminase type 4 (PAD4) in NOD mice were used to further study the effect of NET formation on the progression of T1D. Microbial alterations in Deferribacteres and Proteobacteria, along with the loss of gut barrier function, were found to be associated with increased endotoxin and abnormal formation of NETs in NOD mice. Both DSS-induced colitis and knockout of PAD4 in NOD mice indicated that PAD4-dependent NET formation was involved in the aggravation of gut barrier dysfunction, the production of autoantibodies, and the activation of enteric autoimmune T cells, which then migrated to pancreatic lymph nodes (PLNs) and caused self-damage. The current study thus provides evidence that PAD4-dependent NET formation is engaged in leaky gut triggering pancreatic autoimmunity and suggests that either degradation of NETs or inhibition of NET formation may be helpful for innovative therapeutic interventions in T1D.

Inhibition of PAD4-mediated NET formation by cl-amidine prevents diabetes development in nonobese diabetic mice

Many evidences indicated that neutrophil extracellular traps (NETs) play pathogenic roles in type 1 diabetes (T1D). Peptidylarginine deiminases 4 (PAD4) has been proved to be indispensable for generation of NETs. In the current study, we investigated whether oral administration of cl-amidine, an effective inhibitor of PAD4, protects non-obese diabetic (NOD) mice from T1D development. Female NOD mice were orally administrated with cl-amidine (5 μg/g body weight) from the age of 8 weeks up to 16 weeks. It showed that cl-amidine inhibit NET formation in vitro and in vivo. The onset of T1D was delayed nearly 8 weeks and the incidence of disease was significantly decreased in cl-amidine treated mice compared with the control group. Moreover, cl-amidine decreased the serum levels of anti-citrullinated peptide antibody (ACPA) and anti-neutrophil cytoplasmic antibodies (ANCA) in NOD mice. Also, it decreased generation of T1D autoantibodies such as glutamic acid decarboxylase antibody (GADA), tyrosine phosphatase-related islet antigen-2 antibody (IA2A) and zinc transporter 8 antibody (ZnT8A), which were strongly correlated with the reduced serum PAD4 and MPO-DNA levels. Furthermore, cl-amidine administration inhibited pancreatic inflammation and increased frequency of regulatory T cells in pancreatic lymph nodes (PLNs). In addition, cl-amidine improved gut barrier dysfunction and decreased the serum level of lipopolysaccharide (LPS), which was positively correlated with the NETs markers (PAD4 and MPO-DNA) and T1D autoantibody IA2A. In conclusion, our data showed that orally delivery of cl-amidine effectively prevent T1D development and suggested inhibition of PAD4-dependent NET formation as a potential way of clinical treatment in T1D.

Neutrophils in chronic inflammatory diseases

Chronic inflammation is a component of many disease conditions that affect a large group of individuals worldwide. Chronic inflammation is characterized by persistent, low-grade inflammation and is increased in the aging population. Neutrophils are normally the first responders to acute inflammation and contribute to the resolution of inflammation. However, in chronic inflammation, the role of neutrophils is less well understood and has been described as either beneficial or detrimental, causing tissue damage and enhancing the immune response. Emerging evidence suggests that neutrophils are important players in several chronic diseases, such as atherosclerosis, diabetes mellitus, nonalcoholic fatty liver disease and autoimmune disorders. This review will highlight the interaction of neutrophils with other cells in the context of chronic inflammation, the contribution of neutrophils to selected chronic inflammatory diseases, and possible future therapeutic strategies.

Neutrophils and their role in the aetiopathogenesis of type 1 and type 2 diabetes

Multiple and complex aetiological processes underlie diabetes mellitus, which invariably result in the development of hyperglycaemia. Although there are two prevalent distinct forms of the disease, that is, type 1 and type 2 diabetes, accumulating evidence indicates that these syndromes share more aetiopathological mechanisms than originally thought. This compels a rethinking of the approaches to prevent and treat the different manifestations of what eventually becomes a hyperglycaemic state. This review aims to address the involvement of neutrophils, the most abundant type of granulocytes involved in the initiation of the acute phase of inflammation, in the aetiopathogenesis of diabetes mellitus, with a focus on type 1 and type 2 diabetes. We review the evidence that neutrophils are the first leucocytes to react to and accumulate inside target tissues of diabetes, such as the pancreas and insulin-sensitive tissues. We then review available data on the role of neutrophils and their functional alteration, with a focus on NETosis, in the progression towards clinical disease. Finally, we review potential approaches as secondary and adjunctive treatments to limit neutrophil-mediated damage in the prevention of the progression of subclinical disease to clinical hyperglycaemia.

NETosis in ischemic/reperfusion injuries: An organ-based review

Neutrophil extracellular trap (NETosis), the web-like structures induced by neutrophil death, is an important inflammatory mechanism of the immune system leading to reactive oxygen species production/coagulopathy, endothelial dysfunction, atherosclerosis, and ischemia. NETosis exerts its role through different mechanisms such as triggering Toll-like receptors, inflammatory cytokines, platelet aggregation, neutrophil activation/infiltration, and vascular impairment. NETosis plays a key role in the prognosis of coronary artery disease, ischemic injury of kidney, lung, gastrointestinal tract and skeletal muscles. In this review, we explored the molecular mechanisms involved in NETosis, and ischemic/reperfusion injuries in body organs.

Centrality of Myeloid-Lineage Phagocytes in Particle-Triggered Inflammation and Autoimmunity

Exposure to exogenous particles found as airborne contaminants or endogenous particles that form by crystallization of certain nutrients can activate inflammatory pathways and potentially accelerate autoimmunity onset and progression in genetically predisposed individuals. The first line of innate immunological defense against particles are myeloid-lineage phagocytes, namely macrophages and neutrophils, which recognize/internalize the particles, release inflammatory mediators, undergo programmed/unprogrammed death, and recruit/activate other leukocytes to clear the particles and resolve inflammation. However, immunogenic cell death and release of damage-associated molecules, collectively referred to as "danger signals," coupled with failure to efficiently clear dead/dying cells, can elicit unresolved inflammation, accumulation of self-antigens, and adaptive leukocyte recruitment/activation. Collectively, these events can promote loss of immunological self-tolerance and onset/progression of autoimmunity. This review discusses critical molecular mechanisms by which exogenous particles (i.e., silica, asbestos, carbon nanotubes, titanium dioxide, aluminum-containing salts) and endogenous particles (i.e., monosodium urate, cholesterol crystals, calcium-containing salts) may promote unresolved inflammation and autoimmunity by inducing toxic responses in myeloid-lineage phagocytes with emphases on inflammasome activation and necrotic and programmed cell death pathways. A prototypical example is occupational exposure to respirable crystalline silica, which is etiologically linked to systemic lupus erythematosus (SLE) and other human autoimmune diseases. Importantly, airway instillation of SLE-prone mice with crystalline silica elicits severe pulmonary pathology involving accumulation of particle-laden alveolar macrophages, dying and dead cells, nuclear and cytoplasmic debris, and neutrophilic inflammation that drive cytokine, chemokine, and interferon-regulated gene expression. Silica-induced immunogenic cell death and danger signal release triggers accumulation of T and B cells, along with IgG-secreting plasma cells, indicative of ectopic lymphoid tissue neogenesis, and broad-spectrum autoantibody production in the lung. These events drive early autoimmunity onset and accelerate end-stage autoimmune glomerulonephritis. Intriguingly, dietary supplementation with ω-3 fatty acids have been demonstrated to be an intervention against silica-triggered murine autoimmunity. Taken together, further insight into how particles drive immunogenic cell death and danger signaling in myeloid-lineage phagocytes and how these responses are influenced by the genome will be essential for identification of novel interventions for preventing and treating inflammatory and autoimmune diseases associated with these agents.

Role of nucleic acid sensing in the pathogenesis of type 1 diabetes

During infections, nucleic acids of pathogens are also engaged in recognition via several exogenous and cytosolic pattern recognition receptors, such as the toll-like receptors, retinoic acid inducible gene-I-like receptors, and nucleotide-binding and oligomerization domain-like receptors. The binding of the pathogen-derived nucleic acids to their corresponding sensors initiates certain downstream signaling cascades culminating in the release of type-I interferons (IFNs), especially IFN-α and other cytokines to induce proinflammatory responses towards invading pathogens leading to their clearance from the host. Although these sensors are hardwired to recognize pathogen associated molecular patterns, like viral and bacterial nucleic acids, under unusual physiological conditions, such as excessive cellular stress and increased apoptosis, endogenous self-nucleic acids like DNA, RNA, and mitochondrial DNA are also released. The presence of these self-nucleic acids in extranuclear compartments or extracellular spaces or their association with certain proteins sometimes leads to the failure of discriminating mechanisms of nucleic acid sensors leading to proinflammatory responses as seen in autoimmune disorders, like systemic lupus erythematosus, psoriasis and to some extent in type 1 diabetes (T1D). This review discusses the involvement of various nucleic acid sensors in autoimmunity and discusses how aberrant recognition of self-nucleic acids by their sensors activates the innate immune responses during the pathogenesis of T1D.

Targeting DCs for Tolerance Induction: Don't Lose Sight of the Neutrophils

Chronic inflammatory disorders (CID), such as autoimmune diseases, are characterized by overactivation of the immune system and loss of immune tolerance. T helper 17 (Th17) cells are strongly associated with the pathogenesis of multiple CID, including psoriasis, rheumatoid arthritis, and inflammatory bowel disease. In line with the increasingly recognized contribution of innate immune cells to the modulation of dendritic cell (DC) function and DC-driven adaptive immune responses, we recently showed that neutrophils are required for DC-driven Th17 cell differentiation from human naive T cells. Consequently, recruitment of neutrophils to inflamed tissues and lymph nodes likely creates a highly inflammatory loop through the induction of Th17 cells that should be intercepted to attenuate disease progression. Tolerogenic therapy via DCs, the central orchestrators of the adaptive immune response, is a promising strategy for the treatment of CID. Tolerogenic DCs could restore immune tolerance by driving the development of regulatory T cells (Tregs) in the periphery. In this review, we discuss the effects of the tolerogenic adjuvants vitamin D3 (VD3), corticosteroids (CS), and retinoic acid (RA) on both DCs and neutrophils and their potential interplay. We briefly summarize how neutrophils shape DC-driven T-cell development in general. We propose that, for optimization of tolerogenic DC therapy for the treatment of CID, both DCs for tolerance induction and the neutrophil inflammatory loop should be targeted while preserving the potential Treg-enhancing effects of neutrophils.

Role of Neutrophils on the Ocular Surface

The ocular surface is a gateway that contacts the outside and receives stimulation from the outside. The corneal innate immune system is composed of many types of cells, including epithelial cells, fibroblasts, natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils, mucin, and lysozyme. Neutrophil infiltration and degranulation occur on the ocular surface. Degranulation, neutrophil extracellular traps formation, called NETosis, and autophagy in neutrophils are involved in the pathogenesis of ocular surface diseases. It is necessary to understand the role of neutrophils on the ocular surface. Furthermore, there is a need for research on therapeutic agents targeting neutrophils and neutrophil extracellular trap formation for ocular surface diseases.

Changes in the gut microbiota: a possible factor influencing peripheral blood immune indexes in non-obese diabetic mice

Intestinal flora changes were found in patients and animals with type 1 diabetes (T1D). However, few studies have provided any explicit clues of changes in highly disease related commensal microbiota before disease onset and their relationships with disordered peripheral immune cells. We conducted 16S rRNA microbiota analysis of non-obese diabetic (NOD) mice from weaning to diabetes onset to identify highly disease related microbes and performed Spearman correlation analysis between anomalous flora and peripheral immune cells. We found NOD mice had increased exclusive bacteria and decreased community richness or diversity, besides, with the features of decreased abundance of Bacteroidetes and increased abundance of Firmicutes, Proteobacteria or Deferribacteres and remarkable fluctuations of genus relative abundance. Furthermore, kinds of highly T1D related genus and their strong correlations with peripheral immune cells, especially neutrophils, were discovered. Microbial changes in NOD mice differed from that of ICR mice and highly disease associated microbes have strong correlations with the peripheral neutrophil ratio, which provide evidence that neutrophils are possibly involved in the pathogenesis of T1D.

Elevated Biomarkers of NETosis in the Serum of Pediatric Patients With Type 1 Diabetes and Their First-Degree Relatives

Type 1 diabetes (T1D) is an autoimmune disorder with unambiguous involvement of both innate and adaptive immune mechanisms in the destruction of pancreatic beta cells. Recent evidence demonstrated that neutrophils infiltrate the pancreas prior to disease onset and therein extrude neutrophil extracellular traps (NETs), web-like structures of DNA and nuclear proteins with a strong pro-inflammatory biologic activity. Our previous work showed that T1D NETs activate dendritic cells, which consequently induce IFNγ-producing Th1 lymphocytes. The aim of this study was to assess direct ex vivo biomarkers of NETosis in the serum of recent onset and long-term pediatric T1D patients, their first-degree relatives and healthy controls. To this end we evaluated serum levels of myeloperoxidase (MPO), neutrophil elastase (NE), proteinase 3 (PR3), protein arginine deiminase 4 (PAD4), LL37 and cell-free DNA-histone complexes in sex- and age-matched cohorts of T1D first-degree relatives, recent-onset T1D patients, and in patients 12 months after clinical manifestation of the disease. Our data shows that disease onset is accompanied by peripheral neutrophilia and significant elevation of MPO, NE, PR3, PAD4 and cell-free DNA-histone complexes. Most biomarkers subsequently decrease but do not always normalize in long-term patients. First-degree relatives displayed an intermediate phenotype, except for remarkably high levels of LL37. Together, this report provides evidence for the presence of ongoing NETosis in pediatric patients with T1D at time of clinical manifestation of the disease, which partly subsides in subsequent years.

Increase of Neutrophil Extracellular Traps, Mitochondrial DNA and Nuclear DNA in Newly Diagnosed Type 1 Diabetes Children but Not in High-Risk Children

Neutrophil extracellular traps (NETs) and mitochondrial DNA (mtDNA) are inflammatory mediators involved in the development of type 1 diabetes (T1D). Pancreas-infiltrating neutrophils can release NETs, contributing to the inflammatory process. Levels of NETs are increased in serum from patients with T1D and mtDNA is increased in adult T1D patients. Our aim was to investigate extracellular DNA (NETs, mtDNA and nuclear DNA) in children with newly diagnosed T1D and in children at high risk of the disease. We also elucidated if extracellular DNA short after diagnosis could predict loss of endogenous insulin production. Samples were analysed for mtDNA and nuclear DNA using droplet digital PCR and NETs were assessed by a NET-remnants ELISA. In addition, in vitro assays for induction and degradation of NETs, as well as analyses of neutrophil elastase, HLA genotypes, levels of c-peptide, IL-1beta, IFN and autoantibodies (GADA, IA-2A, IAA and ZnT8A) were performed. In serum from children 10 days after T1D onset there was an increase in NETs (p=0.007), mtDNA (p<0.001) and nuclear DNA (p<0.001) compared to healthy children. The elevated levels were found only in younger children. In addition, mtDNA increased in consecutive samples short after onset (p=0.017). However, levels of extracellular DNA short after onset did not reflect future loss of endogenous insulin production. T1D serum induced NETs in vitro and did not deviate in the ability to degrade NETs. HLA genotypes and autoantibodies, except for ZnT8A, were not associated with extracellular DNA in T1D children. Serum from children with high risk of T1D showed fluctuating levels of extracellular DNA, sometimes increased compared to healthy children. Therefore, extracellular DNA in serum from autoantibody positive high-risk children does not seem to be a suitable biomarker candidate for prediction of T1D. In conclusion, we found increased levels of extracellular DNA in children with newly diagnosed T1D, which might be explained by an ongoing systemic inflammation.

Neutrophil Extracellular Traps Activate Proinflammatory Functions of Human Neutrophils

Neutrophil extracellular traps (NETs) consist of decondensed nuclear chromatin that is associated with proteins and are released by neutrophils during an inflammatory response. Released NETs are able to capture pathogens, prevent their dissemination and potentially kill them via antimicrobial peptides and proteins that are associated with the decondensed chromatin. In addition to their antimicrobial functions, NETs have also been shown to exert immunomodulatory effects by activation and differentiation of macrophages, dendritic cells and T cells. However, the effect of NETs on neutrophil functions is poorly understood. Here we report the first comprehensive study regarding the effects of NETs on human primary neutrophils in vitro. NETs were isolated from cultures of PMA-exposed neutrophils. Exposure of neutrophils to isolated NETs resulted in the activation of several neutrophil functions in a concentration-dependent manner. NETs induced exocytosis of granules, the production of reactive oxygen species (ROS) by the NADPH oxidase NOX2, NOX2-dependent NET formation, increased the phagocytosis and killing of microbial pathogens. Furthermore, NETs induced the secretion of the proinflammatory chemokine IL-8 and the B-cell-activating cytokine BAFF. We could show that the NET-induced activation of neutrophils occurs by pathways that involve the phosphorylation of Akt, ERK1/2 and p38. Taken together our results provide further insights into the proinflammatory role of NETs by activating neutrophil effector function and further supports the view that NETs can amplify inflammatory events. On the one hand the amplified functions enhance the antimicrobial defense. On the other hand, NET-amplified neutrophil functions can be involved in the pathophysiology of NET-associated diseases. In addition, NETs can connect the innate and adaptive immune system by inducing the secretion of the B-cell-activating cytokine BAFF.

Neutrophil Extracellular Traps: A Perspective of Neuroinflammation and Complement Activation in Alzheimer's Disease

Complement system (CS) components are associated with Alzheimer's disease (AD), the commonest cause of dementia in the world. Neutrophils can be attracted to amyloid-β plaques by several pro-inflammatory factors, including the complement anaphylatoxin C5a. They may release neutrophil extracellular traps (NETs), which are chromatin nets associated with myeloperoxidase, elastase, and other enzymes. Some CS molecules, such as C5a, C1q, and CR1, are associated with increased neutrophil recruitment and NETs release. However, the relationship between CS molecules and NETs in AD is poorly understood. In this work, we detected higher NET concentrations in plasma and serum of Brazilian AD patients, than in elderly controls (medians = 2.78 [2.07-6.19] vs. 2.23 [0.33-4.14] ng/mL, p = 0.0005). We discussed these results within the context of our former findings on complement and AD and the context of the literature on complement and NET release, suggesting both as possible therapeutic targets to prevent the progress of the disease.