Neutrophils at work

A DNA-based nanorobot for targeting, hitchhiking, and regulating neutrophils to enhance sepsis therapy

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

Neutrophil single-cell analysis identifies a type II interferon-related subset for predicting relapse of autoimmune small vessel vasculitis

To identify the dynamics of neutrophil autoimmunity, here we focus on anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and perform single-cell transcriptome and surface proteome analyses on peripheral white blood cells from patients with new-onset microscopic polyangiitis (MPA). Compared with controls, two neutrophil populations, immature neutrophils and neutrophils with type II interferon signature genes (Neu_T2ISG), are increased in patients with MPA. Trajectory and cell-cell interaction analyses identify Neu_T2ISG as a subset that differentiates from mature neutrophils upon stimulation with IFN-γ and TNF, which synergize to induce myeloperoxidase and Fcγ receptors expression on the neutrophil cell surface and promote ANCA-induced neutrophil extracellular trap formation. Case-by-case analysis indicates that patients with a high proportion of the Neu_T2ISG subset are associated with persistent vasculitis symptoms. A larger cohort analysis shows that serum IFN-γ levels at disease onset correlate with susceptibility to disease relapse. Our findings thus identify neutrophil diversity at the single cell level and implicate a biomarker for predicting relapse in small vessel vasculitis.

Fc gamma receptors activate different protein kinase C isoforms in human neutrophils

Receptors for FcγR on human neutrophils constitute an important mechanism for the recognition of opsonized microorganisms and for cell activation. Human neutrophils express 2 FcγR: FcγRIIa and FcγRIIIb. Previously, it has been reported that activation of each FcγR induces different neutrophil responses by triggering distinct signal transduction pathways, although what particular signal transduction pathway is triggered by each FcγR has not been completely elucidated. It has also been reported that PKC is important for FcγR signaling and that each FcγR may activate different PKC isoforms. Therefore, we explored whether FcγRIIa or FcγRIIIb activates different PKC isoforms in human neutrophils and whether activation of these PKC isoforms results in different neutrophil responses. Hence, either FcγRIIa or FcγRIIIb was selectively cross-linked by monoclonal antibodies in the presence or absence of pharmacological inhibitors for various PKC isoforms. Inhibition of PKCα or PKCδ blocked FcγRIIa-induced reactive oxygen species productions. In contrast, inhibition of PKCα and/or PKCβ blocked FcγRIIIb-induced reactive oxygen species production. Also, inhibition of all PKC isoforms did not affect the FcγRIIa-induced increase in intracellular calcium concentration ([Ca2+]i), while inhibition of PKCα blocked FcγRIIIb-induced increase in [Ca2+]i. Additionally, inhibition of PKCδ blocked FcγRIIa-induced ERK phosphorylation, while inhibition of PKCα prevented FcγRIIIb-induced ERK phosphorylation. These results suggest that both FcγRIIa and FcγRIIIb activate unique PKC isoforms and that activation of these PKC isoforms can selectively regulate different neutrophil functions. These findings also reinforce the idea that each FcγR in human neutrophils triggers distinct signal transduction pathways.

Adenosine accumulation in the blood of newborn mice weakens antimicrobial host defenses

Pediatric intensive care patients are particularly susceptible to severe bacterial infections because of ineffective neutrophil responses. The reasons why neutrophils of newborns are less responsive than those of adults are not clear. Because adenosine triphosphate and adenosine tightly regulate neutrophils, we studied whether the adenosine triphosphate and adenosine levels in the blood of newborn mice could impair the function of their neutrophils. We observed significant changes in plasma adenosine triphosphate and adenosine levels throughout the lifespan of mice. Adenosine levels in newborns were significantly higher than in older mice, while adenosine triphosphate levels were significantly lower. These changes were particularly striking in newborn and juvenile mice with adenosine triphosphate and adenosine levels of about 80 and 600 nM in newborns vs 130 and 190 nM in juveniles, respectively. The ratios of the adenosine triphosphate vs adenosine levels of newborns were (with 0.2) significantly lower than those of juveniles (1.4) and adults (0.5). These low adenosine triphosphate/adenosine ratios correlated with significantly weakened neutrophil activation responses following in vitro stimulation with a formyl peptide receptor agonist and a markedly higher morbidity and mortality rate of newborns following bacterial infection. We found that enhanced adenosine monophosphate hydrolysis via CD73, a lack of adenosine breakdown by adenosine deaminase, and reduced adenosine uptake by nucleoside transporters are responsible for the low adenosine triphosphate/adenosine ratios in blood of newborn mice. We conclude that the extracellular adenosine accumulation in newborn mice impairs inflammatory responses and reduces the ability of neutrophils to mount effective antimicrobial defenses against bacterial infections.

Flow cytometric measurement of CFTR-mediated chloride transport in human neutrophils

Immune cells express a variety of ion channels and transporters in the plasma membrane and intracellular organelles, responsible of the transference of charged ions across hydrophobic lipid membrane barriers. The correct regulation of ion transport ensures proper immune cell function, activation, proliferation, and cell death. Cystic fibrosis (CF) is a genetic disease in which the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel gene is defective; consequently, the CFTR protein is dysfunctional, and the chloride efflux in CF cells is markedly impaired. CF is characterized by chronic inflammation in the airways, mainly triggered by neutrophilic infiltration and recurring bacterial infections, causing the decline of lung function and eventually respiratory failure. Novel modulator-based therapies have improved lung function in people with CF by increasing expression and function of CFTR in the plasma membrane of lung cells; however, the effects of these drugs in the lung-recruited inflammatory cells, specifically neutrophils, remains unknown. Given the complex biology of neutrophils and their short lifespan, we aimed to develop a fluorometric method to evaluate CFTR-mediated chloride transport in human neutrophils by using flow cytometry and the intracellular chloride-binding MQAE dye. Our results show that CFTR-mediated chloride transport in human neutrophils or human neutrophil-like cell lines can be consistently evaluated in vitro by this methodology. Additionally, this assay measured increased chloride efflux in neutrophils collected from people with CF under modulator therapy, as compared with healthy donors, indicating that this method can evaluate restoration of CFTR-mediated chloride transport in CF neutrophils.

Single-cell and spatial transcriptomics reveal the pathogenesis of chronic granulomatous disease in a natural model

Genetic defects in NADPH oxidase 2 (NOX2) cause chronic granulomatous disease (CGD), which is characterized by increased susceptibility to infections and excessive inflammation leading to granuloma formation. We developed a CGD model using Ncf2-/- mice through controlled environmental exposure. Unlike in specific-pathogen-free environments, these mice spontaneously developed pulmonary granulomas under clean-grade conditions. In the affected lung tissue, significant changes in microbial communities were observed, accompanied by the infiltration of neutrophils and monocyte-derived macrophages (MDMs). Specific nitric oxide synthase 2 (NOS2)high neutrophils with a pro-inflammatory transcriptional profile localize at the granuloma core, while an MDM subpopulation marked by MMP12 at the periphery exhibits a pro-fibrotic signature. Pharmacological inhibition of macrophage migration inhibitory factor (MIF), deletion of the pro-survival gene myeloid RNA regulator of Bim-induced death (Morrbid), and knockout of Il1r1 all suppressed granuloma formation by mitigating inflammation. This study underscores the establishment of a natural CGD model through environmental control, elucidates the mechanisms of granuloma formation, and develops potent therapeutic interventions.

Lipid nanoparticles target neutrophils to reduce SARS-CoV-2-induced lung injury and inflammation

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

LTB4 is converted into a potent human neutrophil NADPH oxidase activator via a receptor transactivation mechanism in which the BLT1 receptor activates the free fatty acid receptor 2

The endogenous neutrophil chemoattractant leukotriene B4 (LTB4) is a biased signalling agonist that potently increases the intracellular concentration of free calcium ions ([Ca2+]i), but alone is a weak activator of the neutrophil superoxide anion (O2-)-generating NADPH oxidase. However, in this study we show that an allosteric modulator of the free fatty acid 2 receptor (FFA2R) converts LTB4 into a potent NADPH oxidase activating agonist. While an allosteric modulation of FFA2R was required for LTB4 receptor 1 (BLT1R)-mediated activation of the NADPH oxidase, the LTB4-induced increase in [Ca2+]i was not affected by the modulator. Thus, the biased BLT1R signalling pattern was altered in the presence of the allosteric FFA2R modulator, being biased with a preference towards the signals that activate the NADPH oxidase relative to an increase in [Ca2+]i. Both BLT1R and FFA2R belong to the family of G protein-coupled receptors (GPCRs), and our results show that a communication between the activated BLT1R and the allosterically modulated FFA2Rs generates signals that induce NADPH oxidase activity. This is consistent with a previously described receptor transactivation (crosstalk) model whereby the function of one neutrophil GPCR can be regulated by receptor downstream signals generated by another GPCR. Furthermore, the finding that an allosteric FFA2R modulator sensitises not only the response induced by orthosteric FFA2R agonists but also the response induced by LTB4, violates the receptor restriction properties that normally define the selectivity of allosteric GPCR modulators.

Neutrophils in Type 1 Diabetes: Untangling the Intricate Web of Pathways and Hypothesis

Neutrophils are increasingly recognized as key contributors to the pathogenesis of Type 1 Diabetes (T1D), yet their precise mechanistic role in disease onset and progression remains incompletely understood. While these innate immune cells reside in pancreatic tissue and support tissue homeostasis under physiological conditions, they can also drive tissue damage by triggering innate immune responses and modulating inflammation. Within the inflammatory milieu, neutrophils establish complex, bidirectional interactions with various immune cells, including macrophages, dendritic cells, natural killer cells, and lymphocytes. Once activated, they may enhance the innate immune response through direct or indirect crosstalk with immune cells, antigen presentation, and β-cell destruction or dysfunction. These mechanisms underscore the multifaceted and dynamic role of neutrophils in T1D, shaped by their intricate immunological interactions. Further research into the diverse functional capabilities of neutrophils is crucial for uncovering novel aspects of their involvement in T1D, potentially revealing new therapeutic targets to modulate disease progression.

Modulating Neutrophil Extracellular Trap Formation In Vivo with Locoregional Precision Using Differently Charged Self-Assembled Hydrogels

Neutrophil extracellular traps (NETs) are DNA networks released by neutrophils, first described as a defense response against pathogens but have since been associated with numerous inflammatory diseases. Diverse physical material properties have been shown to promote NET formation. Herein, we report the discovery that the charge of self-assembled peptide hydrogels predictably modulates the formation of NETs in vivo within the implanted material. Positively charged gels induce rapid NET release, whereas negatively charged gels do not. This differential immune response to our self-assembled peptide gels enabled the development of a material platform that allows rheostat-like modulation over the degree of NET formation with anatomical and locoregional control.

Modulating oxidative stress: a reliable strategy for coping with community-acquired pneumonia in older adults

Community-acquired pneumonia (CAP) remains one of the leading respiratory diseases worldwide. With the aging of the global population, the morbidity, criticality and mortality rates of CAP in older adults remain high every year. Modulating the signaling pathways that cause the inflammatory response and improve the immune function of patients has become the focus of reducing inflammatory damage in the lungs, especially CAP in older adults. As an important factor that causes the inflammatory response of CAP and affects the immune status of the body, oxidative stress plays an important role in the occurrence, development and treatment of CAP. Furthermore, in older adults with CAP, oxidative stress is closely associated with immune senescence, sarcopenia, frailty, aging, multimorbidity, and polypharmacy. Therefore, multiple perspectives combined with the disease characteristics of older adults with CAP were reviewed to clarify the research progress and application value of modulating oxidative stress in older adults with CAP. Clearly, there is no doubt that targeted modulation of oxidative stress benefits CAP in older adults. However, many challenges and unknowns concerning how to modulate oxidative stress for further practical clinical applications exist, and more targeted research is needed. Moreover, the limitations and challenges of modulating oxidative stress are analyzed with the aim of providing references and ideas for future clinical treatment or further research in older adults with CAP.

Investigating pulmonary neutrophil responses to inflammation in mice via flow cytometry

Neutrophils play a crucial role in maintaining lung health by defending against infections and participating in inflammation processes. Here we describe a detailed protocol for evaluating pulmonary neutrophil phenotype using a murine model of sterile inflammation induced by the fungal cell wall particle zymosan. We provide step-by-step instructions for the isolation of single cells from both lung tissues and airspaces, followed by comprehensive staining techniques for both cell surface markers and intracellular components. This protocol facilitates the sorting and detailed characterization of lung neutrophils via flow cytometry, making it suitable for downstream applications such as mRNA extraction, single-cell sequencing, and analysis of neutrophil heterogeneity. We also identify and discuss essential considerations for conducting successful neutrophil flow cytometry experiments. This work is aimed at researchers exploring the intricate functions of neutrophils in the lung under physiological and pathological conditions with the aid of flow cytometry.

Neutrophils Display Novel Partners of Cytosolic Proliferating Cell Nuclear Antigen Involved in Interferon Response in COVID-19 Patients

INTRODUCTION

Neutrophils are key players in the hyperinflammatory response during SARS-CoV-2 infection. The cytosolic proliferating cell nuclear antigen (PCNA) is a scaffolding protein highly dependent on the microenvironment status and known to interact with numerous proteins that regulate neutrophil functions. This study aimed to examine the cytosolic protein content and PCNA interactome in neutrophils from COVID-19 patients.

METHODS

Proteomic analyses were performed on neutrophil cytosols from healthy donors and patients with severe or critical COVID-19. In vitro approaches were used to explore the biological significance of the COVID-19-specific PCNA interactome.

RESULTS

Neutrophil cytosol analysis revealed a strong interferon (IFN) protein signature, with variations according to disease severity. Interactome analysis identified associations of PCNA with proteins involved in interferon signaling, cytoskeletal organization, and neutrophil extracellular trap (NET) formation, such as protein arginine deiminase type-4 (PADI4) and histone H3, particularly in critical patients. Functional studies of interferon signaling showed that T2AA, a PCNA scaffold inhibitor, downregulated IFN-related genes, including STAT1, MX1, IFIT1, and IFIT2 in neutrophils. Additionally, T2AA specifically inhibited the secretion of CXCL10, an IFN-dependent cytokine. PCNA was also found to interact with key effector proteins implicated in NET formation, such as histone H3, especially in critical COVID-19 cases.

CONCLUSION

The analysis of the PCNA interactome has unveiled new protein partners that enhance the interferon pathway, thereby modulating immune responses and contributing to hyperinflammation in COVID-19. These findings provide valuable insights into interferon dysregulation in other immune-related conditions.

INTRODUCTION

Neutrophils are key players in the hyperinflammatory response during SARS-CoV-2 infection. The cytosolic proliferating cell nuclear antigen (PCNA) is a scaffolding protein highly dependent on the microenvironment status and known to interact with numerous proteins that regulate neutrophil functions. This study aimed to examine the cytosolic protein content and PCNA interactome in neutrophils from COVID-19 patients.

METHODS

Proteomic analyses were performed on neutrophil cytosols from healthy donors and patients with severe or critical COVID-19. In vitro approaches were used to explore the biological significance of the COVID-19-specific PCNA interactome.

RESULTS

Neutrophil cytosol analysis revealed a strong interferon (IFN) protein signature, with variations according to disease severity. Interactome analysis identified associations of PCNA with proteins involved in interferon signaling, cytoskeletal organization, and neutrophil extracellular trap (NET) formation, such as protein arginine deiminase type-4 (PADI4) and histone H3, particularly in critical patients. Functional studies of interferon signaling showed that T2AA, a PCNA scaffold inhibitor, downregulated IFN-related genes, including STAT1, MX1, IFIT1, and IFIT2 in neutrophils. Additionally, T2AA specifically inhibited the secretion of CXCL10, an IFN-dependent cytokine. PCNA was also found to interact with key effector proteins implicated in NET formation, such as histone H3, especially in critical COVID-19 cases.

CONCLUSION

The analysis of the PCNA interactome has unveiled new protein partners that enhance the interferon pathway, thereby modulating immune responses and contributing to hyperinflammation in COVID-19. These findings provide valuable insights into interferon dysregulation in other immune-related conditions.

Inhibition of DYRK1B BY C81 impedes inflammatory processes in leukocytes by reducing STAT3 activity

Chronic inflammatory diseases are a significant global burden and are associated with dysregulated resolution of inflammation. Therefore, promoting the process of resolution is a promising therapeutic approach. This study presents the potent anti-inflammatory and pro-resolving effects of a natural product-derived compound called C81. Administration of C81 in a therapeutic window resolved inflammation in the murine imiquimod-induced psoriasis model, and reduced microglial infiltration in a laser-induced choroidal neovascularisation model. Investigations into the underlying mechanisms of C81 identified the DYRK1B/STAT3 axis as a new regulator of inflammatory processes in leukocytes. The inhibition of DYRK1B by C81 resulted in attenuated STAT3 phosphorylation. The depletion of STAT3-regulated gene expression led to the inhibition of leukocyte adhesion and migration due to reduced integrin activation, and in addition to the inhibition of the release of pro-inflammatory mediators such as cytokines and eicosanoids. Importantly, the pro-resolving effects of C81 included the cell type-specific induction of apoptosis in neutrophils and a subsequent increase in efferocytosis. In conclusion, we report the DYRK1B/STAT3 axis as a novel and promising therapeutic target for activating the resolution of inflammation.

The protein tyrosine phosphatase Lyp/PTPN22 drives TNFα-induced priming of superoxide anions production by neutrophils and arthritis

Neutrophils are essential for host defense against infections, but they also play a key role in acute and chronic inflammation. The protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene encodes the lymphoid-specific tyrosine phosphatase (Lyp) and a genetic single-nucleotide polymorphism of PTPN22 rs2476601 (R620W) has been associated with several human autoimmune diseases, including rheumatoid arthritis (RA). Here, we investigated the role of Lyp in TNFα-induced priming of neutrophil ROS production and in the development of arthritis using new selective Lyp inhibitors. Results show that Lyp-selective inhibitors (IC-11 and compound 8b), inhibited TNFα-induced priming of neutrophil superoxide anion production. TNFα induced an increase of Lyp protein expression in human neutrophils isolated from healthy donors. Key pathways involved in neutrophil priming were investigated. Lyp-selective inhibitors, inhibited TNFα-induced p47phox phosphorylation on Ser345, ERK1/2 phosphorylation and Pin1 activation. Interestingly, Lyp expression was increased in neutrophils isolated from synovial fluid of RA patients and Lyp inhibitors, I-C11 and compound 8b prevented superoxide anion production by endogenously primed neutrophils isolated from synovial fluid of RA. Moreover, IC-11 significantly prevented collagen antibody-induced arthritis in mice. These results show that Lyp expression is increased in inflammatory neutrophils, Lyp is involved in TNFα-induced excessive ROS production by neutrophils and its inhibition protected mice against arthritis. Inhibition of Lyp could be a therapeutic strategy in inflammatory arthritis.

Cellular immune responses of bovine polymorphonuclear neutrophils to Calicophoron daubneyi

Calicophoron daubneyi infections have increased in Europe, being more frequent than fasciolosis in some areas. Infection occurs once definitive hosts ingest encysted metacercariae present on vegetation. Following excystation, juvenile flukes penetrate the small intestinal mucosa and migrate into the rumen where adults mature. Throughout the somatic migration, juveniles come across different microenvironments and tissues and encounter host leukocytes. Besides phagocytosis, production of reactive oxygen species (ROS) and degranulation, polymorphonuclear neutrophils also cast neutrophil extracellular traps (NETs), which can entrap several parasite species, including the closely related liver fluke Fasciola hepatica. In this study, we analyzed whether in vitro exposure of bovine neutrophils to C. daubneyi antigen (CdAg) and eggs triggered neutrophils activation and NET formation. Results on scanning electron microscopy (SEM) and immunofluorescence analyses show weak formation of short spread NETs upon CdAg stimulation, corroborated by increased extracellular DNA measurements. Likewise, early NETosis was confirmed via nuclear area expansion assays. Bovine neutrophil stimulation with CdAg 100 µg/mL concentration led to a significant increase in oxygen consumption rates (p = 0.0152) and extracellular acidification rates (p = 0.0022), while lower concentrations of CdAg (10 µg/mL) failed to induce neutrophil activation, suggesting a dose dependent response. Both intra- and extracellular ROS production was not affected by any CdAg concentration here studied. Bovine neutrophil total adenosine triphosphate concentration significantly decreased after exposure to CdAg 100 µg/mL, in line to the observed with the positive control (phorbol myristate acetate/ionomycin). In summary, C. daubneyi activates bovine neutrophils with rather weak responses, which might suggest that the release of C. daubneyi-specific molecules (i.e. excretory-secretory antigens, proteases, or nucleases) could interfere with neutrophil-related effector mechanisms. Further ex vivo analyses will clarify if such mechanisms are also involved in pathogenesis of paramphistomosis by demonstrating neutrophil recruitment into affected intestinal mucosa.

"The NET effect": Neutrophil extracellular traps-a potential key component of the dysregulated host immune response in sepsis

Neutrophils release neutrophil extracellular traps (NETs) as part of a healthy host immune response. NETs physically trap and kill pathogens as well as activating and facilitating crosstalk between immune cells and complement. Excessive or inadequately resolved NETs are implicated in the underlying pathophysiology of sepsis and other inflammatory diseases, including amplification of the inflammatory response and inducing thrombotic complications. Here, we review the growing evidence implicating neutrophils and NETs as central players in the dysregulated host immune response. We discuss potential strategies for modifying NETs to improve patient outcomes and the need for careful patient selection.

Omics analysis reveals galectin-3 to be a potential key regulator of allergic inflammation in hereditary angioedema

Background

Hereditary angioedema (HAE) is a rare inherited disorder that predisposes an individual to develop vasogenic edema. Bradykinin release, which increases vascular permeability, results in angioedema. C1 esterase inhibitor (C1-INH) is a major regulator of critical enzymes involved in bradykinin generation and mutations in genes that encode the C1 inhibitor of complement factor 1, which prevent its synthesis (type I HAE), form a dysfunctional protein (type II HAE), or have normal functioning C1-INH (type III HAE, aka HAE-III).

Objectives

The goals of this study were to use a systems biology analysis to identify novel biomarkers to aid in the diagnosis of HAE-III and to elucidate its underlying pathogenic mechanisms.

Methods

Blood samples were obtained from HAE-III subjects and age- and sex-matched healthy controls. DNA, RNA, and protein purified from the samples were subjected to multiomics analysis using a 1-shot liquid chromatography-mass spectrometry-based multiomics platform (Omni-MS, Dalton Bioanalytics) to profile proteins, lipids, electrolytes, and metabolites enabling concurrent analysis of diverse analyte classes.

Results

A total of 1647 novel identifications that included genes, proteins, and metabolites were made when comparing HAE-III samples to control samples. Our identification library included MSFragger for protein identification, LipiDex for lipid identification, and Compound Discoverer for metabolite identification, enabling differential expression analysis. Key findings included a significant increase in the expression levels of galectin-3, lysosomal α-glucosidase, platelet factor 4, and platelet-derived growth factor subunit A in HAE-III subjects compared to controls, all of which generate an immunomodulatory response.

Conclusion

Galectin-3 plays a critical role in eosinophil recruitment and airway allergic inflammation. It may contribute to chronic inflammation and fibrosis resulting in leaky vasculature, and it could be a potential therapeutic target in HAE-III.

Neutrophil heterogeneity and plasticity: unveiling the multifaceted roles in health and disease

Neutrophils, the most abundant circulating leukocytes, have long been recognized as key players in innate immunity and inflammation. However, recent discoveries unveil their remarkable heterogeneity and plasticity, challenging the traditional view of neutrophils as a homogeneous population with a limited functional repertoire. Advances in single-cell technologies and functional assays have revealed distinct neutrophil subsets with diverse phenotypes and functions and their ability to adapt to microenvironmental cues. This review provides a comprehensive overview of the multidimensional landscape of neutrophil heterogeneity, discussing the various axes along which diversity manifests, including maturation state, density, surface marker expression, and functional polarization. We highlight the molecular mechanisms underpinning neutrophil plasticity, focusing on the complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications that shape neutrophil responses. Furthermore, we explore the implications of neutrophil heterogeneity and plasticity in physiological processes and pathological conditions, including host defense, inflammation, tissue repair, and cancer. By integrating insights from cutting-edge research, this review aims to provide a framework for understanding the multifaceted roles of neutrophils and their potential as therapeutic targets in a wide range of diseases.

Neutrophils, NETs and multiple sclerosis: a mini review

Multiple sclerosis (MS), a chronic inflammatory and degenerative autoimmune disease characterized by the activation of various inflammatory cells, leads to demyelination and neuronal injury. Neutrophils, often underestimated in MS, are gaining increased attention for their significant functions in MS patients and the experimental autoimmune encephalomyelitis (EAE) animal model. Neutrophils play multiple roles in mediating the pathogenesis of autoimmune diseases, and numerous studies suggest that neutrophils might have a crucial role through neutrophil extracellular trap (NET) formation. Studies on NETs in MS are still in their infancy. In this review, we discuss the clinical perspective on the linkage between neutrophils and MS or EAE, as well as the role of NETs in the pathogenesis of MS/EAE. Further, we analyze the potential mechanisms by which NETs contribute to MS, the protective effects of NETs in MS, and their value as targets for disease intervention. NET formation and/or clearance as a therapeutic approach for MS still requires research in greater depth.

Microplastics in the bloodstream can induce cerebral thrombosis by causing cell obstruction and lead to neurobehavioral abnormalities

Human health is being threatened by environmental microplastic (MP) pollution. MPs were detected in the bloodstream and multiple tissues of humans, disrupting the regular physiological processes of organs. Nanoscale plastics can breach the blood-brain barrier, leading to neurotoxic effects. How MPs cause brain functional irregularities remains unclear. This work uses high-depth imaging techniques to investigate the MPs within the brain in vivo. We show that circulating MPs are phagocytosed and lead these cells to obstruction in the capillaries of the brain cortex. These blockages as thrombus formation cause reduced blood flow and neurological abnormalities in mice. Our data reveal a mechanism by which MPs disrupt tissue function indirectly through regulation of cell obstruction and interference with local blood circulation, rather than direct tissue penetration. This revelation offers a lens through which to comprehend the toxicological implications of MPs that invade the bloodstream.

Negative association between the neutrophil percentage-to-albumin ratio (NPAR) and psoriasis: a retrospective cross-sectional study

Among patients with psoriasis, there was not much research regarding the assessment of neutrophil percentage-to-albumin ratio (NPAR) in patients with psoriasis. This cross-sectional study aimed to investigate the association between NPAR and prevalence of psoriasis in US adults. Data from adults aged 20 to 80 years in the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2006 and 2009 to 2014 was utilized. Institutional Review Board approval and documented written consent was obtained from participants by NHANES (Protocol #2005-06). Differences between the groups were further explored. The univariate, multivariate logistic regressions and restricted cubic splines (RCS) regression were used to investigate the correlation between NPAR and psoriasis, with results expressed as odds ratios (OR) and 95% confidence intervals (CI). Subgroup analysis of the associations between NPAR and psoriasis was carried out to investigate if the impact of the NPAR varied among different subgroups. Of the 17,489 adults included in the study, 500 (2.9%) were diagnosed with psoriasis. NPAR (per 10 unit) was negatively associated with prevalence of psoriasis (β = 0.55, 95% CI 0.37, 0.82), after being fully adjusted. A non-linear was observed in the dose-response relationship between NPAR and prevalence of psoriasis (P for non-linearity 0.021). In the subgroup analysis, effect size of NPAR on the presence of psoriasis in subgroups was stable (all P values > 0.05). There exists a stable and strong negative non-linearly association between NPAR and prevalence of psoriasis. The potential role and value in the clinical diagnosis and prognostic assessment of the NPAR in psoriasis calls for further longitudinal studies.

Histone methylation regulates neutrophil extracellular traps to attenuate corneal neovascularization

Corneal neovascularization (CNV) severely affects corneal transparency and disrupts the homeostasis of the ocular environment. However, the underlying mechanism of CNV remains unclear. In this study, we investigated the role of neutrophil extracellular traps (NETs) played in CNV and how histone methylation regulates the characterization of NETs. We used an alkali-burn-induced mice CNV model and human primary neutrophils to observe the involvement of NETs during CNV and change in its histone methylation. Transcriptomic analysis was performed to demonstrate the involvement of NETs during corneal alkali burn. We used the histone demethylase inhibitor JIB-04 to regulate the histone methylation of NETs and explored the related effects on CNV formation. NETs were obviously involved in corneal alkali burn and could be stimulated by NaOH in vitro. Isolated NETs aggravated CNV and promoted migration, proliferation and tube formation of vascular endothelial cells, while disruption of NETs significantly ameliorated angiogenesis and inflammation in vivo and in vitro. Mechanistically, histone methylation of NETs was inhibited by alkali burn and restored by JIB-04. Furthermore, we discovered that JIB-04 reduced CNV and NETs formation by regulating the NF-κB/ERK/ROS pathway. In conclusion, this study claims a novel role for histone methylation in regulating NETs formation and thereby affecting angiogenesis, which indicates a novel therapeutic target for CNV and other neovascularization-related diseases.

Elevated Galectin-3 levels in the tumor microenvironment of ovarian cancer - implication of ROS mediated suppression of NK cell antitumor response via tumor-associated neutrophils

Introduction

Ovarian cancer is a lethal disease with low survival rates for women diagnosed in advanced stages. Current cancer immunotherapies are not efficient in ovarian cancer, and there is therefore a significant need for novel treatment options. The β-galactoside-binding lectin, Galectin-3, is involved in different immune processes and has been associated with poor outcome in various cancer diagnoses. Here, we investigated how Galectin-3 affects the interaction between natural killer (NK) cells and neutrophils in the tumor microenvironment of ovarian cancer.

Method

Ascites from the metastatic tumor microenvironment and cyst fluid from the primary tumor site were collected from patients with high-grade serous carcinoma (HGSC) together with peripheral blood samples. Galectin-3 concentration was measured in ascites, cyst fluid and serum or plasma. Neutrophils isolated from HGSC ascites and autologous blood were analyzed to evaluate priming status and production of reactive oxygen species. In vitro co-culture assays with NK cells, neutrophils and K562 target cells (cancer cell line) were conducted to evaluate NK cell viability, degranulation and cytotoxicity.

Results

High levels of Galectin-3 were observed in cyst fluid and ascites from patients with HGSC. Neutrophils present in HGSC ascites showed signs of priming; however, the priming status varied greatly among the patient samples. Galectin-3 induced production of reactive oxygen species in ascites neutrophils, but only from a fraction of the patient samples, which is in line with the heterogenous priming status of the ascites neutrophils. In co-cultures with NK cells and K562 target cells, we observed that Galectin-3-induced production of reactive oxygen species in neutrophils resulted in decreased NK cell viability and lowered anti-tumor responses.

Conclusion

Taken together, our results demonstrate high levels of Galectin-3 in the tumormicroenvironment of HGSC. High levels of Galectin-3 may induce production of reactiveoxygen species in ascites neutrophils in some patients. In turn, reactive oxygen species produced by neutrophils may modulate the NK cell anti-tumor immunity. Together, this study suggests further investigation to evaluate if a Galectin-3-targeting therapy may be used in ovarian cancer.

The Evolving Role of Neutrophils and Neutrophil Extracellular Traps (NETs) in Obesity and Related Diseases: Recent Insights and Advances

Obesity is a chronic, multifactorial disease characterized by persistent low-grade tissue and systemic inflammation. Fat accumulation in adipose tissue (AT) leads to stress and dysfunctional adipocytes, along with the infiltration of immune cells, which initiates and sustains inflammation. Neutrophils are the first immune cells to infiltrate AT during high-fat diet (HFD)-induced obesity. Emerging evidence suggests that the formation and release of neutrophil extracellular traps (NETs) play a significant role in the progression of obesity and related diseases. Additionally, obesity is associated with an imbalance in gut microbiota and increased intestinal barrier permeability, resulting in the translocation of live bacteria, bacterial deoxyribonucleic acid (DNA), lipopolysaccharides (LPS), and pro-inflammatory cytokines into the bloodstream and AT, thereby contributing to metabolic inflammation. Recent research has also shown that short-chain fatty acids (SCFAs), produced by gut microbiota, can influence various functions of neutrophils, including their activation, migration, and the generation of inflammatory mediators. This review comprehensively summarizes recent advancements in understanding the role of neutrophils and NET formation in the pathophysiology of obesity and related disorders while also focusing on updated potential therapeutic approaches targeting NETs based on studies conducted in humans and animal models.

5-Aminolevulinic Acid (5-ALA) Plays an Important Role in the Function of Innate Immune Cells

5-aminolevulinic acid (5-ALA) is an amino acid essential for the synthesis of heme, which is important for various cellular functions, including the mitochondrial electron transport chain. We previously established heterozygous knockout mice (Alas1+/-) for 5-ALA synthase 1 (ALAS1), the rate-limiting enzyme for 5-ALA synthesis, and reported that the mice developed non-obese insulin-resistant diabetes. In the present study, we used these mice to analyze the role of 5-ALA in the immune system. Using a lipopolysaccharide (LPS)-induced septic shock model, Alas1+/- mice showed reduced mortality compared to wild-type (WT) mice. In this model experiment, the plasma concentration of inflammatory cytokines such as tumor necrosis factor α (TNFα) and interleukin-6 (IL-6), and the chemokine monocyte chemoattractant protein-1 (MCP1) decreased in Alas1+/- mice compared that in WT mice, and inflammatory cell infiltration into the peritoneal cavity was also decreased. In ex vivo experiments, exogenous 5-ALA pretreatment enhanced LPS-induced TNFα and IL-6 production from peripheral blood leukocytes of Alas1+/- mice. Additionally, 5-ALA pretreatment enhanced LPS-induced activation of inflammatory cytokine genes in innate immune cells. Interestingly, the phagocytosis and reactive oxygen species (ROS) producing abilities of neutrophils were clearly hampered in Alas1+/- mice compared to WT mice, but after 2 weeks of 5-ALA administration to Alas1+/- mice, both abilities were significantly recovered up to the level in WT mice. These results reveal that 5-ALA is essential for the function of innate immune cells. Because 5-ALA can be supplemented orally, it has the potential to be used as a drug to restore innate immune function.

The oral-gut microbiome axis in health and disease

The human body hosts trillions of microorganisms throughout many diverse habitats with different physico-chemical characteristics. Among them, the oral cavity and the gut harbour some of the most dense and diverse microbial communities. Although these two sites are physiologically distinct, they are directly connected and can influence each other in several ways. For example, oral microorganisms can reach and colonize the gastrointestinal tract, particularly in the context of gut dysbiosis. However, the mechanisms of colonization and the role that the oral microbiome plays in causing or exacerbating diseases in other organs have not yet been fully elucidated. Here, we describe recent advances in our understanding of how the oral and intestinal microbiota interplay in relation to their impact on human health and disease.

Elevated expression of hsa_circ_0000479 in neutrophils correlates with features of systemic lupus erythematosus

OBJECTIVE

Accumulating evidence suggests that differentially expressed circular RNAs (circRNAs) play critical roles in immune cells of systemic lupus erythematosus (SLE) patients. Hsa_circ_0000479 has been studied in the field of cancer and infection, whereas seldom studied in autoimmune diseases. The aim of this study was to investigate the role and clinical value of neutrophil hsa_circ_0000479 in SLE.

METHODS

The expression levels of hsa_circ_0000479 in both healthy individuals and SLE patients' neutrophils were detected by qPCR and compared with those in peripheral blood mononuclear cells (PBMCs) . In addition, the correlation of hsa_circ_0000479 levels in neutrophils with the clinical and immunological features of SLE patients was also analysed.

RESULTS

The expression levels of hsa_circ_0000479 in the patients with SLE were significantly higher in neutrophils than that of PBMCs, and also significantly higher than that in healthy controls (HCs). Moreover, the expression levels of hsa_circ_0000479 in neutrophils were negatively associated with absolute neutrophil count and complement 3 (C3), whereas positively correlated with anti-dsDNA and anti-nucleosome antibodies in SLE. In addition, SLE patients with higher levels of hsa_circ_0000479 demonstrated more several clinical manifestations, including Raynaud's phenomenon, alopecia and leucopenia.

CONCLUSIONS

Hsa_circ_0000479 is up-regulated in neutrophils of SLE patients, and is also associated with several important laboratory indicators and clinical manifestations, suggesting that hsa_circ_0000479 in neutrophils was one of probable factors involved in the pathogenesis of SLE with potential clinical value.

The role of CEACAMs in neutrophil function

BACKGROUND

In addition to the long-known antibacterial actions of neutrophils, neutrophils are recognized to have a variety of other effects and are functionally diverse. Neutrophils can either stimulate or inhibit B cells and T cells, regulate NK development and activity, augment or direct the resolution of inflammation, act as myeloid-derived suppressor cells, modulate tumour growth and metastasis and trigger autoimmune diseases. CEACAMs 1, 3, 6 and 8 are expressed on human neutrophils.

METHODS

A literature review was performed on the role of CEACAMs in neutrophil function.

RESULTS

CEACAMs 1, 6 and 8 can be upregulated from intracellular stores, while CEACAM3, an opsonin-independent phagocytic receptor, is constitutively expressed. CEACAM1 has an intracellular ITIM motif and an ITSM motif, and CEACAM3 has an ITAM-like motif; CEACAMs 6 and 8 are glycosylphosphatidylinositol-linked. CEACAM8 can also be released in a soluble form. These CEACAMs can interact with multiple other host CEACAMs as well as other molecules on bacteria, fungi and host cells, both transmitting and receiving signals. Known CEACAM-binding pathogens bind the CFG face of the N domain which is also important in CEACAM-CEACAM binding, although the ABDE face also appears to be involved in higher-order oligomers.

CONCLUSIONS

Understanding the exact role of each individual CEACAM in human neutrophils is complicated by the fact that the neutrophil CEACAMs can interact with multiple ligands. The data demonstrates some of the many roles of CEACAMs in neutrophil function and the extensive role of the neutrophil in human biology beyond its classical role as a short-lived phagocyte.

Comprehensive macro and micro views on immune cells in ischemic heart disease

Ischemic heart disease (IHD) is a prevalent cardiovascular condition that remains the primary cause of death due to its adverse ventricular remodelling and pathological changes in end-stage heart failure. As a complex pathologic condition, it involves intricate regulatory processes at the cellular and molecular levels. The immune system and cardiovascular system are closely interconnected, with immune cells playing a crucial role in maintaining cardiac health and influencing disease progression. Consequently, alterations in the cardiac microenvironment are influenced and controlled by various immune cells, such as macrophages, neutrophils, dendritic cells, eosinophils, and T-lymphocytes, along with the cytokines they produce. Furthermore, studies have revealed that Gata6+ pericardial cavity macrophages play a key role in regulating immune cell migration and subsequent myocardial tissue repair post IHD onset. This review outlines the role of immune cells in orchestrating inflammatory responses and facilitating myocardial repair following IHD, considering both macro and micro views. It also discusses innovative immune cell-based therapeutic strategies, offering new insights for further research on the pathophysiology of ischemic heart disease and immune cell-targeted therapy for IHD.

Turning Neutrophil Cell Death Deadly in the Context of Hypertensive Vascular Disease

Hypertensive vascular disease (HVD) is a major health burden globally and is a comorbidity commonly associated with other metabolic diseases. Many factors are associated with HVD including obesity, diabetes, smoking, chronic kidney disease, and sterile inflammation. Increasing evidence points to neutrophils as an important component of the chronic inflammatory response in HVD. Neutrophils are abundant in the circulation and can respond rapidly upon stimulation to deploy an armament of antimicrobial effector functions. One of the outcomes of neutrophil activation is the generation of neutrophil extracellular traps (NETs), a regulated extrusion of chromatin and proteases. Although neutrophils and NETs are well described as components of the innate immune response to infection, recent evidence implicates them in HVD. Endothelial cell activation can trigger neutrophil adhesion, activation, and production of NETs promoting vascular dysfunction, vessel remodelling, and loss of resistance. The regulated release of NETs can be controlled by the pore-forming activities of distinct cell death pathways. The best characterized pathways in this context are apoptosis, pyroptosis, and necroptosis. In this review, we discuss how inflammatory cell death signalling and NET formation contribute to hypertensive disease. We also examine novel therapeutic approaches to limit NET production and their future potential as therapeutic drugs for cardiovascular disorders.

Associations of advanced lung cancer inflammation index with all-cause and respiratory disease mortality in adults with asthma: NHANES, 1999-2018

The Advanced Lung Cancer Inflammation Index (ALI) represents both the inflammatory and nutritional status of the host, but its link with mortality in asthma patients is uncertain. The purpose of this study was to look at the relationship between ALI levels and all-cause and respiratory disease mortality in asthmatic patients. We conducted our research using cohort data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. The National Death Index was used to calculate mortality until December 31, 2019. The study employed multivariate logistic regression to look into the relationship between ALI levels and asthma prevalence. Weighted Kaplan-Meier and multivariate-adjusted Cox analyses were utilized for investigating the relationship between ALI levels and all-cause and respiratory disease mortality in individuals with asthma. A restricted cubic spline (RCS) analysis was used to assess their nonlinear relationship. Subgroup and sensitivity analyses were also performed to evaluate the robustness of the results that were obtained. We enrolled 40,497 people in our study, and 5,469 of them had asthma, representing a 14% prevalence. A median follow-up of 11.19 (9.38, 14.29) years revealed 109 fatalities from respiratory diseases and 724 deaths from all causes. After correcting for several covariates, there was no longer any link (P-trend = 0.2) between ALI levels and the prevalence of asthma. When compared to the lowest quartile, the highest quartile of ALI levels was substantially linked to a lower risk of mortality from respiratory diseases and all causes (all P-trend < 0.001). In the RCS regression model, the relationship between ALI level and both all-cause and respiratory disease mortality in asthmatic participants was nonlinear, with P for nonlinearity of 0.006 and 0.015, respectively. We also discovered that the probability of mortality from respiratory disease decreased progressively to a nadir at an ALI level of 109.13 and then increased as the ALI level increased. Multiple subgroup and sensitivity analyses revealed that ALI was consistently related to lower all-cause and respiratory disease mortality in asthma patients. Our findings suggest that ALI is associated with a reduced risk of all-cause and respiratory disease mortality in asthma patients.

Unraveling the complex role of neutrophils in lymphoma: From pathogenesis to therapeutic approaches (Review)

Lymphoma, a malignancy of the lymphatic system, which is critical for maintaining the body's immune defenses, has become a focal point in recent research due to its intricate interplay with neutrophils-white blood cells essential for combating infections and inflammation. Unlike prior perceptions associating neutrophils only with tumor support, contemporary studies underscore their intricate and multifaceted involvement in the immune response to lymphoma. Recognizing the nuanced participation of neutrophils in lymphoma is crucial for developing innovative treatments to improve patient outcomes.

Cell-mediated nanoparticle delivery systems: towards precision nanomedicine

Cell-mediated nanoparticle delivery systems (CMNDDs) utilize cells as carriers to deliver the drug-loaded nanoparticles. Unlike the traditional nanoparticle drug delivery approaches, CMNDDs take the advantages of cell characteristics, such as the homing capabilities of stem cells, inflammatory chemotaxis of neutrophils, prolonged blood circulation of red blood cells, and internalization of macrophages. Subsequently, CMNDDs can easily prolong the blood circulation, cross biological barriers, such as the blood-brain barrier and the bone marrow-blood barrier, and rapidly arrive at the diseased areas. Such advantageous properties make CMNDDs promising delivery candidates for precision targeting. In this review, we summarize the recent advances in CMNDDs fabrication and biomedical applications. Specifically, ligand-receptor interactions, non-covalent interactions, covalent interactions, and internalization are commonly applied in constructing CMNDDs in vitro. By hitchhiking cells, such as macrophages, red blood cells, monocytes, neutrophils, and platelets, nanoparticles can be internalized or attached to cells to construct CMNDDs in vivo. Then we highlight the recent application of CMNDDs in treating different diseases, such as cancer, central nervous system disorders, lung diseases, and cardiovascular diseases, with a brief discussion about challenges and future perspectives in the end.

Leishmania major surface components and DKK1 signalling via LRP6 promote migration and longevity of neutrophils in the infection site

Background

Host-related factors highly regulate the increased circulation of neutrophils during Leishmania infection. Platelet-derived Dickkopf-1 (DKK1) is established as a high-affinity ligand to LRP6. Recently, we demonstrated that DKK1 upregulates leukocyte-platelet aggregation, infiltration of neutrophils to the draining lymph node and Th2 differentiation during Leishmania infection, suggesting the potential involvement of the DKK1-LRP6 signalling pathway in neutrophil migration in infectious diseases.

Results

In this study, we further explored the potential role of DKK1-LRP6 signalling in the migration and longevity of activated neutrophils in the infection site using BALB/c mice with PMNs deficient in LRP6 (LRP6NKO) or BALB/c mice deficient in both PMN LRP6 and platelet DKK1 (LRP6NKO DKK1PKO). Relative to the infected wild-type BALB/c mice, reduced neutrophil activation at the infection site of LRP6NKO or LRP6NKO DKK1PKO mice was noted. The neutrophils obtained from either infected LRP6NKO or LRP6NKO DKK1PKO mice additionally showed a high level of apoptosis. Notably, the level of LRP6 expressing neutrophils was elevated in infected BALB/c mice. Relative to infected BALB/c mice, a significant reduction in parasite load was observed in both LRP6NKO and LRP6NKO DKK1PKO infected mice. Notably, DKK1 levels were comparable in the LRP6NKO and BALB/c mice in response to infection, indicating that PMN activation is the major pathway for DKK1 in promoting parasitemia. Parasite-specific components also play a crucial role in modulating neutrophil circulation in Leishmania disease. Thus, we further determine the contribution of Leishmania membrane components in the migration of neutrophils to the infection site using null mutants deficient in LPG synthesis (Δlpg1- ) or lacking all ether phospholipids (plasmalogens, LPG, and GIPLs) synthesis (Δads1- ). Relative to the WT controls, Δads1- parasite-infected mice showed a sustained decrease in neutrophils and neutrophil-platelet aggregates (for at least 14 days PI), while neutrophils returned to normal in Δlpg1- parasite-infected mice after day 3 PI.

Conclusion

Our results suggest that DKK1 signalling and Leishmania pathogen-associated molecular patterns appear to regulate the migration and sustenance of viable activated neutrophils in the infection site resulting in chronic type 2 cell-mediated inflammation.

The Potential Role of Reactive Oxygen Species Produced by Low-Density Neutrophils in Periodontitis

OBJECTIVE

 Neutrophils own an arsenal of dischargeable chemicals that enable them to handle bacterial challenges, manipulating innate immune response and actual participation in acquired immunity. The reactive oxygen species (ROS) are one of the most important chemicals that neutrophils discharge to eradicate pathogens. Despite their beneficial role, the ROS were strongly correlated to periodontal tissue destruction. Lowdensity neutrophils (LDN) have been recognized for producing enhanced quantities of ROS. However, the potential role of ROS produced by LDN in periodontitis is unknown. The aim of the study was to investigate the impact of ROS produced by LDN in periodontal diseases.

MATERIALS AND METHODS

 Venous blood and periodontal parameters were obtained from 100 systemically healthy subjects divided into 40 participants with healthy periodontium in the control group and 60 with unstable periodontitis in the study group. Flow cytometry was used to measure the production of ROS by LDN in both groups.

STATISTICAL ANALYSIS

 The data were analyzed for normal distribution using the Shapiro-Wilk test at p < 0.05, Spearman's correlations, and Mann-Whitney U test. Statistical analysis was performed in SPSS v25.

RESULTS

 No difference between the groups had been obtained in ROS production by LDN. However, a significant positive correlation existed between ROS and clinical attachment loss in periodontitis.

CONCLUSION

 LDN exhibits the same ROS generation capacity in the control and periodontitis groups.

Erianin alleviates LPS-induced acute lung injury via antagonizing P-selectin-mediated neutrophil adhesion function

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium officinale Kimura et Migo, known as "Tiepi Shihu" in traditional Chinese medicine, boasts an extensive history of medicinal use documented in the Chinese Pharmacopoeia. "Shen Nong Ben Cao Jing" records D. officinale as a superior herbal medicine for fortifying "Yin" and invigorating the five viscera. Erianin, a benzidine compound, emerges as a prominent active constituent derived from D. officinale, with the pharmacological efficacy of D. officinale closely linked to the anti-inflammatory properties of erianin.

AIM OF THE STUDY

Acute lung injury (ALI) is a substantial threat to global public health, while P-selectin stands out as a promising novel target for treating acute inflammatory conditions. This investigation aims to explore the therapeutic potential of erianin in ALI treatment and elucidate the underlying mechanisms.

EXPERIMENTAL DESIGN

The effectiveness of erianin in conferring protection against ALI was investigated through comprehensive histopathological and biochemical analyses of lung tissues and bronchoalveolar lavage fluid (BALF) in an in vivo model of LPS-induced ALI in mice. The impact of erianin on fMLP-induced neutrophil chemotaxis was quantitatively assessed using the Transwell and Zigmond chamber, respectively. To determine the therapeutic target of erianin and elucidate their binding capability, a series of sophisticated assays were employed, including drug affinity responsive target stability (DARTS) assay, cellular thermal shift assay (CETSA), and molecular docking analyses.

RESULTS

Erianin demonstrated a significant alleviation of LPS-induced acute lung injury, characterized by reduced total cell and neutrophil counts and diminished total protein contents in BALF. Moreover, erianin exhibited a capacity to decrease proinflammatory cytokine production in both lung tissues and BALF. Notably, erianin effectively suppressed the activation of NF-κB signaling in the lung tissues of LPS- challenged mice; however, it did not exhibit in vitro inhibitory effects on inflammation in LPS-induced human pulmonary microvascular endothelial cells (HPMECs). Additionally, erianin blocked the adhesion and rolling of neutrophils on HPMECs. While erianin did not influence endothelial P-selectin expression or cytomembrane translocation, it significantly reduced the ligand affinity between P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1).

CONCLUSIONS

Erianin inhibits P-selectin-mediated neutrophil adhesion to activated endothelium, thereby alleviating ALI. The present study highlights the potential of erianin as a promising lead for ALI treatment.

Neutrophil-fibroblast crosstalk drives immunofibrosis in Crohn's disease through IFNα pathway

INTRODUCTION

Crohn's disease (CD) is characterized by chronic inflammation and intestinal fibrosis leading to lifelong complications. However, the disease pathogenesis remains elusive, and the therapeutic options are limited. Here, we investigated the interaction between neutrophils and intestinal fibroblasts in the development of CD immunofibrosis, a disease mechanism predisposing to inflammatory and fibrotic complications.

METHODS

Peripheral neutrophils, enriched neutrophil extracellular traps (eNETs), serum, primary intestinal fibroblasts (PIFs) and intestinal biopsies from CD, ulcerative colitis (UC) patients, and healthy individuals (HI), were studied. Transcriptome analysis of neutrophils, multi-cytokine profiling and cell-based functional assays at mRNA/protein level were performed.

RESULTS

Compared to UC, PIFs from CD patients, independently to the presence of strictures, displayed a distinct pro-fibrotic phenotype characterized by negative Krüppellike Factor-2 (KLF2) and increased cellular communication network factor-2 (CCN2) expression leading to collagen production. In both UC and CD, PIFs-derived IL-8 acted as a culprit chemoattractant for neutrophils in the intestine, where CD neutrophils were accumulated close to fibrotic lesions. Functionally, only CD neutrophils via eNETs induced a CD-like phenotype in HI PIFs, suggesting their fibrotic plasticity. High IFNa in serum and IFΝ-responsive signature in peripheral neutrophils were observed in CD, distinguishing it from UC. Moreover, CD serum stimulated the release of fibrogenic eNETs from neutrophils in an IFNa-dependent manner, suggesting the priming role of IFNa in circulating neutrophils. Inhibition of eNETs or JAK signaling in neutrophils or PIFs prevented the neutrophil-mediated fibrotic effect on PIFs. Furthermore, both serum IFNa levels and mRNA levels of key IFN signaling components in neutrophils were wellcorrelated with CD severity.

CONCLUSIONS

This study reveals the important role of the IFNa/neutrophil/fibroblast axis in CD immunofibrosis, suggesting candidate biomarkers and putative therapeutic targets.

Estimation of reference interval for neutrophil activity evaluation systems: a interim report

Neutrophils play an important role in innate immunity and produce reactive oxygen species, but they can also cause inflammation and oxidative stress that can damage their own tissues. We have developed neutrophil activity evaluation systems that simultaneously monitors superoxide radicals and hypochlorite ions secreted by stimulated neutrophils in a few microliters of whole blood and have conducted clinical studies in humans. Here, we report normal reference intervals with our systems based on the results of 3,082 persons who underwent comprehensive cancer screening between February 2020 and March 2022. A total of 344 were extracted as reference individuals based on the results of the cancer screening and the reference intervals of the two systems were interim estimated considering gender and age. Reference intervals can be used as a marker of sub-clinical inflam-mation, which is difficult to detect with other blood markers.

The mitochondrial translocator protein (TSPO, 18 kDa): A key multifunctional molecule in liver diseases

Translocator protein (TSPO, 18 kDa), previously known as peripheral-type benzodiazepine receptor, is an evolutionarily conserved and tryptophan-rich 169-amino-acid protein located on the outer mitochondrial membrane. TSPO plays a crucial role in various fundamental physiological functions and cellular processes. Its expression is altered in pathological conditions, thus rendering TSPO a potential tool for diagnostic imaging and an appealing therapeutic target. The investigation of synthetic TSPO ligands as both agonists and antagonists has provided valuable insights into the regulatory mechanisms and functional properties of TSPO. Recently, accumulating evidence has highlighted the significance of TSPO in liver diseases. However, a comprehensive summary of TSPO function in the normal liver and diverse liver diseases is lacking. This review aims to provide an overview of recent advances in understanding TSPO function in both normal liver cells and various liver diseases, with a particular emphasis on its involvement in liver fibrosis and inflammation and addresses the existing knowledge gaps in the field that require further investigation.

Inhibition of neutrophil rolling and migration by caADAMTS13 in vitro and in mouse models of thrombosis and inflammation

Recent investigation of a constitutively active ADAMTS13 variant (caADAMTS13) in murine models of acute ischaemic stroke (AIS) have revealed a potential anti-inflammatory mechanism of action contributing to its protective effect. However, it remains unclear whether these observations are a direct result of VWF proteolysis by caADAMTS13. We have implemented state of the art in vitro assays of neutrophil rolling and transmigration to quantify the impact of caADAMTS13 on these processes. Moreover, we have tested caADAMTS13 in two in vivo assays of neutrophil migration to confirm the impact of the treatment on the neutrophil response to sterile inflammation. Neutrophil rolling, over an interleukin-1β stimulated hCMEC/D3 monolayer, is directly inhibited by caADAMTS13, reducing the proportion of neutrophils rolling to 9.5 ± 3.8 % compared to 18.0 ± 4.5 % in untreated controls. Similarly, neutrophil transmigration recorded in real-time, was significantly suppressed in the presence of caADAMTS13 which reduced the number of migration events to a level like that in unstimulated controls (18.0 ± 4.5 and 15.8 ± 7.5 cells/mm2/h, respectively). Brain tissue from mice undergoing experimental focal cerebral ischaemia has indicated the inhibition of this process by caADAMTS13. This is supported by caADAMTS13's ability to reduce neutrophil migration into the peritoneal cavity in an ischaemia-independent model of sterile inflammation, with the VWF-dependent mechanism by which this occurs being confirmed using a second experimental stroke model. These findings will be an important consideration in the further development of caADAMTS13 as a potential therapy for AIS and other thromboinflammatory pathologies, including cardiovascular disease.

Oxygen-generating biomaterials for cardiovascular engineering: unveiling future discoveries

Oxygen-generating biomaterials are emerging as a groundbreaking solution for transforming cardiovascular engineering. These biomaterials generate and release oxygen within various biomedical applications, marking a new frontier in healthcare. Most cardiovascular treatments face a significant challenge, ensuring a consistent oxygen supply to nurture engineered tissues or even implanted devices. Traditional methods relying on passive oxygen diffusion often fall short, hindering functional cardiovascular tissue development. Oxygen-generating biomaterials, incorporating agents like calcium peroxide, provide a controlled oxygen source to the surrounding cells. This innovation potentially enhances cell viability, stimulates growth and boosts metabolic activity crucial for tissue health. Applications include repairing cardiac and vascular tissues, disease modeling, drug testing and personalized medicine, promising tailored treatments. Challenges like material toxicity and oxygen release control need consideration. As research progresses, the use of these innovative biomaterials in clinical translation could reshape cardiovascular healthcare, revolutionizing patient outcomes in heart disease treatment.

How neutrophils shape the immune response of triple-negative breast cancer: Novel therapeutic strategies targeting neutrophil extracellular traps

Triple-negative breast cancer (TNBC) is labeled as an aggressive type of breast cancer and still has limited therapeutic targets despite the advanced development of cancer therapy. Neutrophils, representing the conventional inflammatory response, significantly influence the malignant phenotype of tumors, supported by abundant evidence. As a vital function of neutrophils, NETs are the extracellular fibrous networks including the depolymerized chromatin DNA frames with several antimicrobial proteins. They are produced by activated neutrophils and are involved in host defence or immunological reactions. This review focuses more on the interactions between neutrophils and TNBC, focusing on how neutrophils modulate the immune response within the tumor milieu. Specifically, we delve into the role of NETs, which are involved in promoting tumor growth and metastasis, inhibiting anti-tumor immunity, and promoting tumor-associated thrombosis. Furthermore, we discuss recent advancements in therapeutic strategies aimed at targeting NETs to enhance the efficacy of TNBC treatment. The advances in the knowledge of the dynamics between neutrophils and TNBC may lead to the opportunity to devise new immunotherapeutic strategies targeted to fight this hostile type of breast cancer.

The clinical significance of inflammatory biomarkers, IL6 cytokine, and systemic immune inflammatory index in rabbit model of acute and chronic Methicillin-resistant Staphylococcus epidermidis-induced osteomyelitis

Infections are a major complication of open fractures and fracture fixation. In this study, an innovative bioactive medical device was used to experimentally treat MRSE-induced osteomyelitis in rabbit tibia. This paper investigates the clinical significance of inflammatory biomarkers (NLR, PLR, MLR and PMR), SII and IL-6 and assesses their role in the development of osteomyelitis. The main objective is to identify the utility of hematological reports derived from neutrophils, leukocytes, monocytes and platelets in the evolution of implant-related osteomyelitis and the estimation of treatment efficiency. In particular, this study compares the response of these inflammatory markers to different treatments in the presence or absence of bioactive materials and/or topical antibiotics over time. The analysis of the threads showed that NLR, PLR and SII had high values in the acute phase of the disease, so that after chronicization, they decrease. The animals treated with vancomycin nano-functionalized peptide-enriched silk fibroin-coated implants showed lower levels of inflammatory biomarkers compared to the other groups (empty implants and peptide-enriched silk fibroin-coated implants). NLR, PLR and SII, complemented by IL-6 can be used as fairly accurate biomarkers for the diagnosis of osteomyelitis.

The peptidyl-prolyl isomerase Pin1 controls GM-CSF-induced priming of NADPH oxidase in human neutrophils and priming at inflammatory sites

The production of superoxide anions and other reactive oxygen species (ROS) by neutrophils is necessary for host defense against microbes. However, excessive ROS production can induce cell damage that participates in the inflammatory response. Superoxide anions are produced by the phagocyte NADPH oxidase, a multicomponent enzyme system consisting of two transmembrane proteins (gp91phox/NOX2 and p22phox) and four soluble cytosolic proteins (p40phox, p47phox, p67phox and the small G proteins Rac1/2). Stimulation of neutrophils by various agonists, such as the bacterial peptide formyl-Met-Leu-Phe (fMLF), induces NADPH oxidase activation and superoxide production, a process that is enhanced by the pro-inflammatory cytokines such as GM-CSF. The pathways involved in this GM-CSF-induced up-regulation or priming are not fully understood. Here we show that GM-CSF induces the activation of the prolyl cis/trans isomerase Pin1 in human neutrophils. Juglone and PiB, two selective Pin1 inhibitors, were able to block GM-CSF-induced priming of ROS production by human neutrophils. Interestingly, GM-CSF induced Pin1 binding to phosphorylated p47phox at Ser345. Neutrophils isolated from synovial fluid of patients with rheumatoid arthritis are known to be primed. Here we show that Pin1 activity was also increased in these neutrophils and that Pin1 inhibitors effectively inhibited ROS hyperproduction by the same cells. These results suggest that the prolyl cis/trans isomerase Pin1 may control GM-CSF-induced priming of ROS production by neutrophils and priming of neutrophils in synovial fluid of rheumatoid arthritis patients. Pharmacological targeting of Pin1 may be a valuable approach to the treatment of inflammation.

Marginated Neutrophils in the Lungs Effectively Compete for Nanoparticles Targeted to the Endothelium, Serving as a Part of the Reticuloendothelial System

Nanomedicine has long pursued the goal of targeted delivery to specific organs and cell types but has yet to achieve this goal with the vast majority of targets. One rare example of success in this pursuit has been the 25+ years of studies targeting the lung endothelium using nanoparticles conjugated to antibodies against endothelial surface molecules. However, here we show that such "endothelial-targeted" nanocarriers also effectively target the lungs' numerous marginated neutrophils, which reside in the pulmonary capillaries and patrol for pathogens. We show that marginated neutrophils' uptake of many of these "endothelial-targeted" nanocarriers is on par with endothelial uptake. This generalizes across diverse nanomaterials and targeting moieties and was even found with physicochemical lung tropism (i.e., without targeting moieties). Further, we observed this in ex vivo human lungs and in vivo healthy mice, with an increase in marginated neutrophil uptake of nanoparticles caused by local or distant inflammation. These findings have implications for nanomedicine development for lung diseases. These data also suggest that marginated neutrophils, especially in the lungs, should be considered a major part of the reticuloendothelial system (RES), with a special role in clearing nanoparticles that adhere to the lumenal surfaces of blood vessels.

Dysregulation of neutrophil oxidant production and interleukin-1-related cytokines in granulomatosis with polyangiitis

OBJECTIVES

Neutrophils play a key role in ANCA-associated vasculitis, both as targets of autoimmunity and as facilitators of vascular damage. In granulomatosis with polyangiitis (GPA), the data regarding the production of reactive oxygen species (ROS) in neutrophils are unclear. Further, recent data suggests that ROS production could have an anti-inflammatory effect through the regulation of inflammasomes and IL-1-related cytokines. We aimed to analyse ROS production in neutrophils from patients with GPA and investigate its association with IL-1-related cytokines and the autoantigen PR3.

METHODS

Seventy-two GPA patients with disease flare were included in the NEUTROVASC prospective cohort study. ROS production in whole blood of patients with active GPA was evaluated and compared with that in the same patients in remission or healthy controls. Associations between ROS production, PR3 membrane expression on neutrophils, serum levels of IL-1-related cytokines as well as inflammasome-related proteins were analysed.

RESULTS

We observed a robust defect in ROS production by neutrophils from patients with active GPA compared with healthy controls, independent of glucocorticoid treatment. Serum levels of IL-1-related cytokines were significantly increased in GPA patients, particularly in patients with kidney involvement, and levels of these cytokines returned to normal after patients achieved remission. Further, inflammasome-related proteins were significantly dysregulated in the cytosol of neutrophils as well as the serum from GPA patients.

CONCLUSION

Our data suggests that ROS production and regulation of inflammasomes in neutrophils from patients with GPA are disturbed and may be a potential therapeutic target.

TRIAL REGISTRATION

ClinicalTrials.gov, https://www.clinicaltrials.gov, NCT01862068.

Drug repurposing of cyclin-dependent kinase inhibitors for neutrophilic acute respiratory distress syndrome and psoriasis

BACKGROUND

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

AIM OF REVIEW

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

KEY SCIENTIFIC CONCEPTS OF REVIEW

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

Phytochemical Composition and Biological Activity of the Essential Oil from Ericameria nauseosa Collected in Southwestern Montana, United States

Ericameria nauseosa (Pall. ex Pursh) G.L. Nesom & G.I. Baird) is used in traditional medicine to treat various diseases; however, little is known about the immunomodulatory activity of essential oil from this plant. Thus, we isolated essential oil from the aerial parts of E. nauseosa and evaluated their chemical composition and biological activity. Compositional analysis of E. nauseosa essential oil revealed that the main (>2%) components were γ-decalactone (13.3%), cryptone (9.4%), terpinen-4-ol (9.3%), (E)-methyl cinnamate (6.0%), T-cadinol (4.7%), spathulenol (3.6%), 8Z-2,3-dihydromatricaria ester (3.1%), β-phellandrene (3.0%), p-cymen-8-ol (2.2%), 3-ethoxy-2-cycloocten-1-one (2.2%), and trans-p-menth-2-en-1-ol (2.1%). Distinctive features were the lactones (up to 15%) and polyacetylenes (up to 3.1%), including (2Z,8Z)-matricaria ester and 8Z-2,3-dihydromatricaria ester. A comparison with other reported E. nauseosa essential oil samples showed that our samples were distinct from those collected in other areas of the country; however, they did have the most similarity to one sample collected in North Central Utah. Pharmacological studies showed that E. nauseosa essential oil activated human neutrophil Ca2+ influx, which desensitized these cells to subsequent agonist-induced functional responses. Based on our previously reported data that nerolidol, β-pinene, spathulenol, sabinene, and γ-terpinene were active in human neutrophils, these compounds are the most likely constituents contributing to this immunomodulatory activity. However, the relatively high amount of polyacetylenes may also contribute, as these compounds have been characterized as potent immunomodulators.

NETosis-Inspired Cell Surface-Constrained Framework Nucleic Acids Traps (FNATs) for Cascaded Extracellular Recognition and Cellular Behavior Modulation

Upon pathogenic stimulation, activated neutrophils release nuclear DNA into the extracellular environment, forming web-like DNA structures known as neutrophil extracellular traps (NETs), which capture and kill bacteria, fungi, and cancer cells. This phenomenon is commonly referred to as NETosis. Inspired by this, we introduce a cell surface-constrained web-like framework nucleic acids traps (FNATs) with programmable extracellular recognition capability and cellular behavior modulation. This approach facilitates dynamic key chemical signaling molecule recognition such as adenosine triphosphate (ATP), which is elevated in the extracellular microenvironment, and triggers FNA self-assembly. This, in turn, leads to in situ tightly interwoven FNAs formation on the cell surface, thereby inhibiting target cell migration. Furthermore, it activates a photosensitizer-capturing switch, chlorin e6 (Ce6), and induces cell self-destruction. This cascade platform provides new potential tools for visualizing dynamic extracellular activities and manipulating cellular behaviors using programmable in situ self-assembling DNA molecular devices.