Neutrophils as emerging therapeutic targets

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.

Comprehensive bioinformatics analysis of a RBM family-based prognostic signature with experiment validation in hepatocellular carcinoma

BACKGROUND

Although some RBM proteins family members play important roles in hepatocellular carcinoma (HCC) development, their value of prognosis and tumor treatment is not clear. To reveal the expression patterns and clinical significance of RBM family members in HCC, we constructed a RBM family-based prognosis signature.

METHOD

We collected the data of HCC patients from TCGA and ICGC database. The prognostic signature was constructed in TCGA and verified using ICGC cohort. Based on this model, risk score was calculated and patients were divided into high- and low-risk group. Comparison of immune cell infiltration, the response to immunotherapy, and IC50 of chemotherapeutic drugs were employed between different risk subgroups. Besides, CCK-8 and EdU assays were performed to investigate the role of RBM45 in HCC.

RESULT

Among 19 differential expression RBM protein family genes, 7 prognostic genes were picked out. Through LASSO Cox regression, a 4-gene prognostic model was successfully constructed, which included RBM8A, RBM19, RBM28 and RBM45. Results of validation and estimation suggested this model could be applied for prognostic prediction in HCC patients with a well predictive value. Risk score was shown to be an independent predictor and high-risk patients had poor prognosis. High-risk patients had an immunosuppressive tumor microenvironment while patients with low risk could benefit more from ICI therapy and sorafenib treatment. In addition, knockdown of RBM45 inhibited the proliferation of HCC.

CONCLUSION

This prognostic signature based on RBM family had a great value for predicting OS of HCC patients. Low-risk patients were more suitable for receiving immunotherapy and sorafenib treatment. The RBM family members made of the prognostic model might promote the progression of HCC.

Intrinsically bioactive and biomimetic nanoparticle-derived therapies alleviate asthma by regulating multiple pathological cells

Asthma is a serious global public health concern. Airway neutrophilic inflammation is closely related to severe asthma, for which effective and safe therapies remain to be developed. Here we report nanotherapies capable of simultaneously regulating multiple target cells relevant to the pathogenesis of neutrophilic asthma. A nanotherapy LaCD NP based on a cyclic oligosaccharide-derived bioactive material was engineered. LaCD NP effectively accumulated in the injured lungs of asthmatic mice and mainly distributed in neutrophils, macrophages, and airway epithelial cells after intravenous or inhalation delivery, thereby ameliorating asthmatic symptoms and attenuating pulmonary neutrophilic inflammation as well as reducing airway hyperresponsiveness, remodeling, and mucus production. Surface engineering via neutrophil cell membrane further enhanced targeting and therapeutic effects of LaCD NP. Mechanistically, LaCD NP can inhibit the recruitment and activation of neutrophils, especially reducing the neutrophil extracellular traps formation and NLRP3 inflammasome activation in neutrophils. Also, LaCD NP can suppress macrophage-mediated pro-inflammatory responses and prevent airway epithelial cell death and smooth muscle cell proliferation, by mitigating neutrophilic inflammation and its direct effects on relevant cells. Importantly, LaCD NP showed good safety performance. Consequently, LaCD-derived multi-bioactive nanotherapies are promising for effective treatment of neutrophilic asthma and other neutrophil-associated diseases.

Hand infection: a management approach based on a new understanding of combined bacterial and neutrophil mediated tissue damage

Concepts of tissue damage from sepsis are rooted in the works of Pasteur regarding colonization by microorganisms, and Lister's observation of avoiding suppuration by their exclusion. The reactive inflammation has been considered a beneficial defence mechanism. A more complex biology is now unfolding of pathogenic mechanisms with toxins produced by the organisms now being placed in a broad category of virulence factors. Neutrophils are key cells in providing innate immunity and their trafficking to sites of infection results in entry to the extracellular space where they attack pathogens by release of the contents of neutrophil granules and neutrophil extracellular traps. There is now considerable evidence that much of the tissue damage in infection is due to excessive host innate immunological reaction; a hyperinflammatory response, whether localized or systemic. In addition to traditional surgical methods of drainage and decompression there is now a focus on dilution of inflammatory mediators. This emerging knowledge can potentially alter the way we approach hand infections.

The intricate relationship between autoimmunity disease and neutrophils death patterns: a love-hate story

Autoimmune diseases are pathological conditions that result from the misidentification of self-antigens in immune system, leading to host tissue damage and destruction. These diseases can affect different organs and systems, including the blood, joints, skin, and muscles. Despite the significant progress made in comprehending the underlying pathogenesis, the complete mechanism of autoimmune disease is still not entirely understood. In autoimmune diseases, the innate immunocytes are not functioning properly: they are either abnormally activated or physically disabled. As a vital member of innate immunocyte, neutrophils and their modes of death are influenced by the microenvironment of different autoimmune diseases due to their short lifespan and diverse death modes. Related to neutrophil death pathways, apoptosis is the most frequent cell death form of neutrophil non-lytic morphology, delayed or aberrant apoptosis may contribute to the development anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). In addition, NETosis, necroptosis and pyroptosis which are parts of lytic morphology exacerbate disease progression through various mechanisms in autoimmune diseases. This review aims to summarize recent advancements in understanding neutrophil death modes in various autoimmune diseases and provide insights into the development of novel therapeutic approaches for autoimmune diseases.

Neutrophils exacerbate acetaminophen-induced liver injury by producing cytotoxic interferon-γ

BACKGROUND

Drug (e.g., acetaminophen, APAP)-associated hepatotoxicity is the major cause of acute liver failure. Emerging evidence shows that initial tissue damage caused by APAP triggers molecular and cellular immune responses, which can modulate the severity of hepatoxicity. The pro-inflammatory and cytotoxic cytokine interferon (IFN)-γ has been reported as a key molecule contributing to APAP-induced liver injury (AILI). However, its cellular source remains undetermined.

RESULTS

In the current study, we show that elevation of serum IFN-γ in patients with drug hepatotoxicity correlates with disease severity. Neutralization of IFN-γ in a mouse model of AILI effectively reduces hepatotoxicity. Strikingly, we reveal that IFN-γ is expressed primarily by hepatic neutrophils, not by conventional immune cells with known IFN-γ-producing capability, e.g., CD8+ T cells, CD4+ T cells, natural killer cells, or natural killer T cells. Upon encountering APAP-injured hepatocytes, neutrophils secrete cytotoxic IFN-γ further causing cell stress and damage, which can be abrogated in the presence of blocking antibodies for IFN-γ or IFN-γreceptor. Furthermore, removal of neutrophils in vivo substantially decreases hepatic IFN-γ levels concomitantly with reduced APAP hepatotoxicity, whereas adoptive transfer of IFN-γ-producing neutrophils confers IFN-γ-/- mice susceptibility to APAP administration.

CONCLUSIONS

Our findings uncover a novel mechanism of neutrophil action in promoting AILI and provide new insights into immune modulation of the disease pathogenesis.

Harnessing neutrophil plasticity for HCC immunotherapy

Neutrophils, until recently, have typically been considered a homogeneous population of terminally differentiated cells with highly conserved functions in homeostasis and disease. In hepatocellular carcinoma (HCC), tumour-associated neutrophils (TANs) are predominantly thought to play a pro-tumour role, promoting all aspects of HCC development and progression. Recent developments in single-cell technologies are now providing a greater insight and appreciation for the level of cellular heterogeneity displayed by TANs in the HCC tumour microenvironment, which we have been able to correlate with other TAN signatures in datasets for gastric cancer, pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer (NSCLC). TANs with classical pro-tumour signatures have been identified as well as neutrophils primed for anti-tumour functions that, if activated and expanded, could become a potential therapeutic approach. In recent years, therapeutic targeting of neutrophils in HCC has been typically focused on impairing the recruitment of pro-tumour neutrophils. This has now been coupled with immune checkpoint blockade with the aim to stimulate lymphocyte-mediated anti-tumour immunity whilst impairing neutrophil-mediated immunosuppression. As a result, neutrophil-directed therapies are now entering clinical trials for HCC. Pharmacological targeting along with ex vivo reprogramming of neutrophils in HCC patients is, however, in its infancy and a greater understanding of neutrophil heterogeneity, with a view to exploit it, may pave the way for improved immunotherapy outcomes. This review will cover the recent developments in our understanding of neutrophil heterogeneity in HCC and how neutrophils can be harnessed to improve HCC immunotherapy.

Neutrophil extracellular traps and long COVID

Post-acute COVID-19 sequelae, commonly known as long COVID, encompasses a range of systemic symptoms experienced by a significant number of COVID-19 survivors. The underlying pathophysiology of long COVID has become a topic of intense research discussion. While chronic inflammation in long COVID has received considerable attention, the role of neutrophils, which are the most abundant of all immune cells and primary responders to inflammation, has been unfortunately overlooked, perhaps due to their short lifespan. In this review, we discuss the emerging role of neutrophil extracellular traps (NETs) in the persistent inflammatory response observed in long COVID patients. We present early evidence linking the persistence of NETs to pulmonary fibrosis, cardiovascular abnormalities, and neurological dysfunction in long COVID. Several uncertainties require investigation in future studies. These include the mechanisms by which SARS-CoV-2 brings about sustained neutrophil activation phenotypes after infection resolution; whether the heterogeneity of neutrophils seen in acute SARS-CoV-2 infection persists into the chronic phase; whether the presence of autoantibodies in long COVID can induce NETs and protect them from degradation; whether NETs exert differential, organ-specific effects; specifically which NET components contribute to organ-specific pathologies, such as pulmonary fibrosis; and whether senescent cells can drive NET formation through their pro-inflammatory secretome in long COVID. Answering these questions may pave the way for the development of clinically applicable strategies targeting NETs, providing relief for this emerging health crisis.

Precise nanodrug delivery systems with cell-specific targeting for ALI/ARDS treatment

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common acute and critical diseases in clinics and have no effective treatment to date. With the concept of "precision medicine", research into the precise drug delivery of therapeutic and diagnostic drugs has become a frontier in nanomedicine research and has entered the era of design of precise nanodrug delivery systems (NDDSs) with cell-specific targeting. Owing to the distinctive characteristics of ALI/ARDS, designing NDDSs for specific focal sites is an important strategy for changing drug distribution in the body and specifically increasing drug concentration at target sites while decreasing drug concentration at non-target sites. This strategy enhances drug efficacy, reduces adverse reactions, and ensures accurate nano-targeted treatment. On the basis of the characteristics of pathological ALI/ARDS microenvironments, this paper reviews NDDSs targeting vascular endothelial cells, neutrophils, alveolar macrophages, and alveolar epithelial cells to provide reference for designing accurate NDDSs for ALI/ARDS and novel insights into targeted treatments for ALI/ARDS.

Whole-genome screens reveal regulators of differentiation state and context-dependent migration in human neutrophils

Neutrophils are the most abundant leukocyte in humans and provide a critical early line of defense as part of our innate immune system. We perform a comprehensive, genome-wide assessment of the molecular factors critical to proliferation, differentiation, and cell migration in a neutrophil-like cell line. Through the development of multiple migration screen strategies, we specifically probe directed (chemotaxis), undirected (chemokinesis), and 3D amoeboid cell migration in these fast-moving cells. We identify a role for mTORC1 signaling in cell differentiation, which influences neutrophil abundance, survival, and migratory behavior. Across our individual migration screens, we identify genes involved in adhesion-dependent and adhesion-independent cell migration, protein trafficking, and regulation of the actomyosin cytoskeleton. This genome-wide screening strategy, therefore, provides an invaluable approach to the study of neutrophils and provides a resource that will inform future studies of cell migration in these and other rapidly migrating cells.

E-64c-Hydrazide Based Cathepsin C Inhibitors: Optimizing the Interactions with the S1'-S2' Area

The zymogens of the neutrophil serine proteases elastase, proteinase 3, and cathepsin G are converted proteolytically into their pro-inflammatory active forms by the action of cathepsin C. The inhibition of this cysteine protease therefore is an interesting therapeutic approach for the treatment of inflammatory disorders with a high neutrophil burden such as COPD. Based on E-64c-hydrazide as lead structure, we have recently developed a covalently acting cathepsin C inhibitor using a n-butyl residue attached at the amine nitrogen of the hydrazide moiety to efficiently address the deep hydrophobic S2 pocket. To further optimize the affinity and selectivity profile of this inhibitor, the S1'-S2' area was now investigated by a combinatorial approach, showing that Nle-tryptamide is a ligand superior to the initially used Leu-isoamylamide. Using the neutrophil precursor line U937 as a cell culture model, this optimized inhibitor blocks the intracellular cathepsin C activity and thereby suppresses the activation of neutrophil elastase.

Therapeutic inhibition of CXCR1/2: where do we stand?

Mounting experimental evidence from in vitro and in vivo animal studies points to an essential role of the CXCL8-CXCR1/2 axis in neutrophils in the pathophysiology of inflammatory and autoimmune diseases. In addition, the pathogenetic involvement of neutrophils and the CXCL8-CXCR1/2 axis in cancer progression and metastasis is increasingly recognized. Consequently, therapeutic targeting of CXCR1/2 or CXCL8 has been intensively investigated in recent years using a wide array of in vitro and animal disease models. While a significant benefit for patients with unwanted neutrophil-mediated inflammatory conditions may be expected from a potential clinical use of inhibitors, their use in severe infections or sepsis might be problematic and should be carefully and thoroughly evaluated in animal models and clinical trials. Translating the approaches using inhibitors of the CXCL8-CXCR1/2 axis to cancer therapy is definitively a new and promising research avenue, which parallels the ongoing efforts to clearly define the involvement of neutrophils and the CXCL8-CXCR1/2 axis in neoplastic diseases. Our narrative review summarizes the current literature on the activation and inhibition of these receptors in neutrophils, key inhibitor classes for CXCR2 and the therapeutic relevance of CXCR2 inhibition focusing here on gastrointestinal diseases.

Blood-brain crosstalk: the roles of neutrophils, platelets, and neutrophil extracellular traps in neuropathologies

Systemic inflammation, neurovascular dysfunction, and coagulopathy often occur concurrently in neuropathologies. Neutrophils and platelets have crucial synergistic roles in thromboinflammation and are increasingly suspected as effector cells contributing to the pathogenesis of neuroinflammatory diseases. In this review, we summarize the roles of platelet-neutrophil interactions in triggering complex pathophysiological events affecting the brain that may lead to the disruption of brain barriers, infiltration of toxic factors into the parenchyma, and amplification of neuroinflammation through the formation of neutrophil extracellular traps (NETs). We highlight the clinical significance of thromboinflammation in neurological disorders and examine the contributions of damage-associated molecular patterns (DAMPs) derived from platelets and neutrophils. These DAMPs originate from both infectious and non-infectious risk factors and contribute to the activation of inflammasomes during brain disorders. Finally, we identify knowledge gaps in the molecular mechanisms underlying neurodegenerative disease pathogenesis and emphasize the potential of interventions targeting platelets and neutrophils to treat neuroinflammatory diseases.

PAD2: A potential target for tumor therapy

Peptide arginine deiminase 2(PAD2) catalyzes the conversion of arginine residues on target proteins to citrulline residues in the presence of calcium ions. This particular posttranslational modification is called citrullination. PAD2 can regulate the transcriptional activity of genes through histone citrullination and nonhistone citrullination. In this review, we summarize the evidence from recent decades and systematically illustrate the role of PAD2-mediated citrullination in tumor pathology and the regulation of tumor-associated immune cells such as neutrophils, monocytes, macrophages and T cells. Several PAD2-specific inhibitors are also presented to discuss the feasibility of anti-PAD2 therapy to treat tumors and the urgent problems to be solved. Finally, we review some recent developments in the development of PAD2 inhibitors.

Revolutionizing cancer treatment: The power of cell-based drug delivery systems

Intravenous administration of drugs is a widely used cancer therapy approach. However, the efficacy of these drugs is often hindered by various biological barriers, including circulation, accumulation, and penetration, resulting in poor delivery to solid tumors. Recently, cell-based drug delivery platforms have emerged as promising solutions to overcome these limitations. These platforms offer several advantages, including prolonged circulation time, active targeting, controlled release, and excellent biocompatibility. Cell-based delivery systems encompass cell membrane coating, intracellular loading, and extracellular backpacking. These innovative platforms hold the potential to revolutionize cancer diagnosis, monitoring, and treatment, presenting a plethora of opportunities for the advancement and integration of pharmaceuticals, medicine, and materials science. Nevertheless, several technological, ethical, and financial barriers must be addressed to facilitate the translation of these platforms into clinical practice. In this review, we explore the emerging strategies to overcome these challenges, focusing specifically on the functions and advantages of cell-mediated drug delivery in cancer treatment.

The double-edged role of neutrophil heterogeneity in inflammatory diseases and cancers

Neutrophils are important immune cells act as the body's first line of defense against infection and respond to diverse inflammatory cues. Many studies have demonstrated that neutrophils display plasticity in inflammatory diseases and cancers. Clarifying the role of neutrophil heterogeneity in inflammatory diseases and cancers will contribute to the development of novel treatment strategies. In this review, we have presented a review on the development of the understanding on neutrophil heterogeneity from the traditional perspective and a high-resolution viewpoint. A growing body of evidence has confirmed the double-edged role of neutrophils in inflammatory diseases and tumors. This may be due to a lack of precise understanding of the role of specific neutrophil subsets in the disease. Thus, elucidating specific neutrophil subsets involved in diseases would benefit the development of precision medicine. Thusly, we have summarized the relevance and actions of neutrophil heterogeneity in inflammatory diseases and cancers comprehensively. Meanwhile, we also discussed the potential intervention strategy for neutrophils. This review is intended to deepen our understanding of neutrophil heterogeneity in inflammatory diseases and cancers, while hold promise for precise treatment of neutrophil-related diseases.

Butyrate regulates neutrophil homeostasis and impairs early antimicrobial activity in the lung

Short-chain fatty acids (SCFAs) are metabolites that are produced after microbial fermentation of dietary fiber and impact cell metabolism and anti-inflammatory pathways both locally in the gut and systemically. In preclinical models, administration of SCFAs, such as butyrate, ameliorates a range of inflammatory disease models including allergic airway inflammation, atopic dermatitis, and influenza infection. Here we report the effect of butyrate on a bacteria-induced acute neutrophil-driven immune response in the airways. Butyrate impacted discrete aspects of hematopoiesis in the bone marrow resulting in the accumulation of immature neutrophils. During Pseudomonas aeruginosa infection, butyrate treatment led to the enhanced mobilization of neutrophils to the lungs as a result of increased CXCL2 expression by lung macrophages. Despite this increase in granulocyte numbers and their enhanced phagocytic capacity, neutrophils failed to control early bacterial growth. Butyrate reduced the expression of nicotinamide adenine dinucleotide phosphate, oxidase complex components required for reactive oxygen species production, and reduced secondary granule enzymes, culminating in impaired bactericidal activity. These data reveal that SCFAs tune neutrophil maturation and effector function in the bone marrow under homeostatic conditions, potentially to mitigate against excessive granulocyte-driven immunopathology, but their consequently restricted bactericidal capacity impairs early control of Pseudomonas infection.

Cell type-specific roles of NLRP3, inflammasome-dependent and -independent, in host defense, sterile necroinflammation, tissue repair, and fibrosis

The NLRP3 inflammasome transforms a wide variety of infectious and non-infectious danger signals that activate pro-inflammatory caspases, which promote the secretion of IL-1β and IL-18, and pyroptosis, a pro-inflammatory form of cell necrosis. Most published evidence documents the presence and importance of the NLRP3 inflammasome in monocytes, macrophages, and neutrophils during host defense and sterile forms of inflammation. In contrast, in numerous unbiased data sets, NLRP3 inflammasome-related transcripts are absent in non-immune cells. However, an increasing number of studies report the presence and functionality of the NLRP3 inflammasome in almost every cell type. Here, we take a closer look at the reported cell type-specific expression of the NLRP3 inflammasome components, review the reported inflammasome-dependent and -independent functions, and discuss possible explanations for this discrepancy.

Inhibition of NETosis via PAD4 alleviated inflammation in giant cell myocarditis

Giant cell myocarditis (GCM) is a rare, usually rapidly progressive, and potentially fatal disease. Detailed inflammatory responses remain unknown, in particular the formation of multinucleate giant cells. We performed single-cell RNA sequencing analysis on 15,714 Cd45+ cells extracted from the hearts of GCM rats and normal rats. NETosis has been found to contribute to the GCM process. An inhibitor of NETosis, GSK484, alleviated GCM inflammation in vivo. MPO (a marker of neutrophils) and H3cit (a marker of NETosis) were expressed at higher levels in patients with GCM than in patients with DCM and healthy controls. Imaging mass cytometry analysis revealed that immune cell types within multinucleate giant cells included CD4+ T cells, CD8+ T cells, neutrophils, and macrophages but not B cells. We elucidated the role of NETosis in GCM pathogenesis, which may serve as a potential therapeutic target in the clinic.

Myeloid Src-family kinases are critical for neutrophil-mediated autoinflammation in gout and motheaten models

Autoinflammatory diseases include a number of monogenic systemic inflammatory diseases, as well as acquired autoinflammatory diseases such as gout. Here, we show that the myeloid Src-family kinases Hck, Fgr, and Lyn are critical for experimental models of gout, as well as for genetically determined systemic inflammation in the Ptpn6me-v/me-v (motheaten viable) mouse model. The Hck-/-Fgr-/-Lyn-/- mutation abrogated various monosodium urate (MSU) crystal-induced pro-inflammatory responses of neutrophils, and protected mice from the development of gouty arthritis. The Src-family inhibitor dasatinib abrogated MSU crystal-induced responses of human neutrophils and reduced experimental gouty arthritis in mice. The Hck-/-Fgr-/-Lyn-/- mutation also abrogated spontaneous inflammation and prolonged the survival of the Ptpn6me-v/me-v mice. Spontaneous adhesion and superoxide release of Ptpn6me-v/me-v neutrophils were also abolished by the Hck-/-Fgr-/-Lyn-/- mutation. Excessive activation of tyrosine phosphorylation pathways in myeloid cells may characterize a subset of autoinflammatory diseases.

TIME Is Ticking for Cervical Cancer

Cervical cancer (CC) is a major health problem among reproductive-age females and comprises a leading cause of cancer-related deaths. Human papillomavirus (HPV) is the major risk factor associated with CC incidence. However, lifestyle is also a critical factor in CC pathogenesis. Despite HPV vaccination introduction, the incidence of CC is increasing worldwide. Therefore, it becomes critical to understand the CC tumor immune microenvironment (TIME) to develop immune cell-based vaccination and immunotherapeutic approaches. The current article discusses the immune environment in the normal cervix of adult females and its role in HPV infection. The subsequent sections discuss the alteration of different immune cells comprising CC TIME and their targeting as future therapeutic approaches.

Interaction molecular QTL mapping discovers cellular and environmental modifiers of genetic regulatory effects

Bulk tissue molecular quantitative trait loci (QTLs) have been the starting point for interpreting disease-associated variants, while context-specific QTLs show particular relevance for disease. Here, we present the results of mapping interaction QTLs (iQTLs) for cell type, age, and other phenotypic variables in multi-omic, longitudinal data from blood of individuals of diverse ancestries. By modeling the interaction between genotype and estimated cell type proportions, we demonstrate that cell type iQTLs could be considered as proxies for cell type-specific QTL effects. The interpretation of age iQTLs, however, warrants caution as the moderation effect of age on the genotype and molecular phenotype association may be mediated by changes in cell type composition. Finally, we show that cell type iQTLs contribute to cell type-specific enrichment of diseases that, in combination with additional functional data, may guide future functional studies. Overall, this study highlights iQTLs to gain insights into the context-specificity of regulatory effects.

Chemotactic NO/H2S Nanomotors Realizing Cardiac Targeting of G-CSF against Myocardial Ischemia-Reperfusion Injury

Recombinant granulocyte colony-stimulating factor (G-CSF), with a direct repair effect on injured cardiomyocytes against myocardial infarction ischemia-reperfusion-injury (IRI), displays a poor effect owing to the limited cardiac targeting efficacy. There are almost no reports of nanomaterials that deliver G-CSF to the IRI site. Herein, we propose a way to protect G-CSF by constructing one layer of nitric oxide (NO)/hydrogen sulfide (H₂S) nanomotors on its outside. NO/H₂S nanomotors with specific chemotactic ability to high expression of reactive oxygen species (ROS)/induced nitric oxide synthase (iNOS) at the IRI site can deliver G-CSF to the IRI site efficiently. Meanwhile, superoxide dismutase is covalently bound to the outermost part, reducing ROS at the IRI site through a cascade effect with NO/H₂S nanomotors. The synergistic effect between NO and H₂S on the effective regulation of the IRI microenvironment can not only avoid toxicity caused by excessive concentration of a single gas but also reduce inflammation level and relieve calcium overload, so as to promote G-CSF to play a cardioprotective role.

Dock2 generates characteristic spatiotemporal patterns of Rac activity to regulate neutrophil polarisation, migration and phagocytosis

Introduction

Rac-GTPases and their Rac-GEF activators play important roles in neutrophil-mediated host defence. These proteins control the adhesion molecules and cytoskeletal dynamics required for neutrophil recruitment to inflamed and infected organs, and the neutrophil effector responses that kill pathogens.

Methods

Here, we used live cell TIRF-FRET imaging in neutrophils from Rac-FRET reporter mice with deficiencies in the Rac-GEFs Dock2, Tiam1 or Prex1/Vav1 to evaluate if these proteins activate spatiotemporally distinct pools of Rac, and to correlate patterns of Rac activity with the neutrophil responses they control.

Results

All the GEFs were required for neutrophil adhesion, and Prex1/Vav1 were important during spreading and for the velocity of migration during chemotaxis. However, Dock2 emerged as the prominent regulator of neutrophil responses, as this GEF was required for neutrophil polarisation and random migration, for migration velocity during chemokinesis, for the likelihood to migrate and for the speed of migration and of turning during chemotaxis, as well as for rapid particle engulfment during phagocytosis. We identified characteristic spatiotemporal patterns of Rac activity generated by Dock2 which correlate with the importance of the Rac-GEF in these neutrophil responses. We also demonstrate a requirement for Dock2 in neutrophil recruitment during aseptic peritonitis.

Discussion

Collectively, our data provide a first direct comparison of the pools of Rac activity generated by different types of Rac-GEFs, and identify Dock2 as a key regulator of polarisation, migration and phagocytosis in primary neutrophils.

Attenuation of LPS-Induced Lung Injury by Benziodarone via Reactive Oxygen Species Reduction

As overproduction of reactive oxygen species (ROS) causes various diseases, antioxidants that scavenge ROS, or inhibitors that suppress excessive ROS generation, can be used as therapeutic agents. From a library of approved drugs, we screened compounds that reduced superoxide anions produced by pyocyanin-stimulated leukemia cells and identified benzbromarone. Further investigation of several of its analogues showed that benziodarone possessed the highest activity in reducing superoxide anions without causing cytotoxicity. In contrast, in a cell-free assay, benziodarone induced only a minimal decrease in superoxide anion levels generated by xanthine oxidase. These results suggest that benziodarone is an inhibitor of NADPH oxidases in the plasma membrane but is not a superoxide anion scavenger. We investigated the preventive effect of benziodarone on lipopolysaccharide (LPS)-induced murine lung injury as a model of acute respiratory distress syndrome (ARDS). Intratracheal administration of benziodarone attenuated tissue damage and inflammation via its ROS-reducing activity. These results indicate the potential application of benziodarone as a therapeutic agent against diseases caused by ROS overproduction.

The value of basement membrane-associated genes in the prognosis and immune regulation of glioma

Gliomas have a high incidence rate in central nervous tumors. Although many breakthroughs have been made in the pathogenesis and treatment of glioma, the recurrence and metastasis rates of patients have not been improved based on the uniqueness of glioma. Glioma destroys the surrounding basement membrane (BM), leading to local infiltration, resulting in the corresponding clinical and neurological symptoms. Therefore, exploring the biological roles played by BM associated genes in glioma is particularly necessary for a comprehensive understanding of the biological processes of glioma and its treatment. Differential expression and univariate COX regression analyses were used to identify the basement membrane genes (BMGs) to be included in the model. LASSO regression was used to construct the BMG model. The Kaplan-Meier (KM) survival analysis model was used to assess the prognosis discrimination between training sets, validation sets, and clinical subgroups. Receiver-operating characteristic (ROC) analysis was used to test the prognostic efficacy of the model. Use calibration curves to verify the accuracy of nomograms. Gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG), and gene set enrichment analysis (GSEA) were used to analyze the function and pathway enrichment among the model groups. ESTIMATE and other 7 algorithms including CIBERSORT were used to evaluate the immune microenvironment. "pRRophetic" was used to evaluate drug sensitivity. This study demonstrated that high-risk genes (LAMB4, MMP1, MMP7) promote glioma progression and negatively correlate with patient prognosis. In the tumor microenvironment (TME), high-risk genes have increased scores of macrophages, neutrophils, immune checkpoints, chemokines, and chemokine receptors. This study suggests that BMGs, especially high-risk-related genes, are potential sites for glioma therapy, a new prospect for comprehensively understanding the molecular mechanism of glioma.

Functional responsiveness of in vitro-aged human neutrophils

Elimination of apoptotic neutrophils by macrophages is as a major step for the resolution of inflammation. However, the fate and the cellular functionality of neutrophils aged in the absence of macrophages are not well documented. Herein, freshly isolated human neutrophils were aged for several days in vitro and then stimulated with agonists for determining their cell responsiveness. In vitro-aged neutrophils were still able to generate reactive oxygen species after 48 h, exert phagocytosis after 72 h, and increase their adhesion onto a cell substratum after 48 h. These data demonstrate that a portion of neutrophils cultivated for several days in vitro are still able to exert biological functions. This opens the possibility that, during inflammation, neutrophils may still respond to agonists, a condition that is likely to occur in vivo when they are not efficiently eliminated by efferocytosis.

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

INTRODUCTION

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

METHODOLOGY

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

RESULTS

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

CONCLUSION

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

Chimera and Tandem-Repeat Type Galectins: The New Targets for Cancer Immunotherapy

In humans, a total of 12 galectins have been identified. Their intracellular and extracellular biological functions are explored and discussed in this review. These galectins play important roles in controlling immune responses within the tumour microenvironment (TME) and the infiltration of immune cells, including different subsets of T cells, macrophages, and neutrophils, to fight against cancer cells. However, these infiltrating cells also have repair roles and are hijacked by cancer cells for pro-tumorigenic activities. Upon a better understanding of the immunomodulating functions of galectin-3 and -9, their inhibitors, namely, GB1211 and LYT-200, have been selected as candidates for clinical trials. The use of these galectin inhibitors as combined treatments with current immune checkpoint inhibitors (ICIs) is also undergoing clinical trial investigations. Through their network of binding partners, inhibition of galectin have broad downstream effects acting on CD8⁺ cytotoxic T cells, regulatory T cells (Tregs), Natural Killer (NK) cells, and macrophages as well as playing pro-inflammatory roles, inhibiting T-cell exhaustion to support the fight against cancer cells. Other galectin members are also included in this review to provide insight into potential candidates for future treatment(s). The pitfalls and limitations of using galectins and their inhibitors are also discussed to cognise their clinical application.

Cell-based and cell-free immunotherapies for glioblastoma: current status and future directions

Glioblastoma (GBM) is among the most fatal and recurring malignant solid tumors. It arises from the GBM stem cell population. Conventional neurosurgical resection, temozolomide (TMZ)-dependent chemotherapy and radiotherapy have rendered the prognosis of patients unsatisfactory. Radiotherapy and chemotherapy can frequently induce non-specific damage to healthy brain and other tissues, which can be extremely hazardous. There is therefore a pressing need for a more effective treatment strategy for GBM to complement or replace existing treatment options. Cell-based and cell-free immunotherapies are currently being investigated to develop new treatment modalities against cancer. These treatments have the potential to be both selective and successful in minimizing off-target collateral harm in the normal brain. In this review, several aspects of cell-based and cell-free immunotherapies related to GBM will be discussed.

ATG5 provides host protection acting as a switch in the atg8ylation cascade between autophagy and secretion

ATG5 is a part of the E3 ligase directing lipidation of ATG8 proteins, a process central to membrane atg8ylation and canonical autophagy. Loss of Atg5 in myeloid cells causes early mortality in murine models of tuberculosis. This in vivo phenotype is specific to ATG5. Here, we show using human cell lines that absence of ATG5, but not of other ATGs directing canonical autophagy, promotes lysosomal exocytosis and secretion of extracellular vesicles and, in murine Atg5fl/fl LysM-Cre neutrophils, their excessive degranulation. This is due to lysosomal disrepair in ATG5 knockout cells and the sequestration by an alternative conjugation complex, ATG12-ATG3, of ESCRT protein ALIX, which acts in membrane repair and exosome secretion. These findings reveal a previously undescribed function of ATG5 in its host-protective role in murine experimental models of tuberculosis and emphasize the significance of the branching aspects of the atg8ylation conjugation cascade beyond the canonical autophagy.

Radiation-induced tumor immune microenvironments and potential targets for combination therapy

As one of the four major means of cancer treatment including surgery, radiotherapy (RT), chemotherapy, immunotherapy, RT can be applied to various cancers as both a radical cancer treatment and an adjuvant treatment before or after surgery. Although RT is an important modality for cancer treatment, the consequential changes caused by RT in the tumor microenvironment (TME) have not yet been fully elucidated. RT-induced damage to cancer cells leads to different outcomes, such as survival, senescence, or death. During RT, alterations in signaling pathways result in changes in the local immune microenvironment. However, some immune cells are immunosuppressive or transform into immunosuppressive phenotypes under specific conditions, leading to the development of radioresistance. Patients who are radioresistant respond poorly to RT and may experience cancer progression. Given that the emergence of radioresistance is inevitable, new radiosensitization treatments are urgently needed. In this review, we discuss the changes in irradiated cancer cells and immune cells in the TME under different RT regimens and describe existing and potential molecules that could be targeted to improve the therapeutic effects of RT. Overall, this review highlights the possibilities of synergistic therapy by building on existing research.

Neutrophil (dys)function due to altered immuno-metabolic axis in type 2 diabetes: implications in combating infections

Metabolic and inflammatory pathways are highly interdependent, and both systems are dysregulated in Type 2 diabetes (T2D). T2D is associated with pre-activated inflammatory signaling networks, aberrant cytokine production and increased acute phase reactants which leads to a pro-inflammatory 'feed forward loop'. Nutrient 'excess' conditions in T2D with hyperglycemia, elevated lipids and branched-chain amino acids significantly alter the functions of immune cells including neutrophils. Neutrophils are metabolically active cells and utilizes energy from glycolysis, stored glycogen and β-oxidation while depending on the pentose phosphate pathway for NADPH for performing effector functions such as chemotaxis, phagocytosis and forming extracellular traps. Metabolic changes in T2D result in constitutive activation and impeded acquisition of effector or regulatory activities of neutrophils and render T2D subjects for recurrent infections. Increased flux through the polyol and hexosamine pathways, elevated production of advanced glycation end products (AGEs), and activation of protein kinase C isoforms lead to (a) an enhancement in superoxide generation; (b) the stimulation of inflammatory pathways and subsequently to (c) abnormal host responses. Neutrophil dysfunction diminishes the effectiveness of wound healing, successful tissue regeneration and immune surveillance against offending pathogens. Hence, Metabolic reprogramming in neutrophils determines frequency, severity and duration of infections in T2D. The present review discusses the influence of the altered immuno-metabolic axis on neutrophil dysfunction along with challenges and therapeutic opportunities for clinical management of T2D-associated infections.

CAR-neutrophil mediated delivery of tumor-microenvironment responsive nanodrugs for glioblastoma chemo-immunotherapy

Glioblastoma (GBM) is one of the most aggressive and lethal solid tumors in human. While efficacious therapeutics, such as emerging chimeric antigen receptor (CAR)-T cells and chemotherapeutics, have been developed to treat various cancers, their effectiveness in GBM treatment has been hindered largely by the blood-brain barrier and blood-brain-tumor barriers. Human neutrophils effectively cross physiological barriers and display effector immunity against pathogens but the short lifespan and resistance to genome editing of primary neutrophils have limited their broad application in immunotherapy. Here we genetically engineer human pluripotent stem cells with CRISPR/Cas9-mediated gene knock-in to express various anti-GBM CAR constructs with T-specific CD3ζ or neutrophil-specific γ-signaling domains. CAR-neutrophils with the best anti-tumor activity are produced to specifically and noninvasively deliver and release tumor microenvironment-responsive nanodrugs to target GBM without the need to induce additional inflammation at the tumor sites. This combinatory chemo-immunotherapy exhibits superior and specific anti-GBM activities, reduces off-target drug delivery and prolongs lifespan in female tumor-bearing mice. Together, this biomimetic CAR-neutrophil drug delivery system is a safe, potent and versatile platform for treating GBM and possibly other devastating diseases.

Investigation of Diagnostic and Prognostic Value of CLEC4M of Non-Small Cell Lung Carcinoma Associated with Immune Microenvironment

Purpose

C-type lectin domain family 4 member M (CLEC4M) has been found to be involved in the occurrence and development of cancer, but its role in NSCLC remains to be fully explored. Our work aims to evaluate the diagnostic and prognostic value of CLEC4M in NSCLC and to investigate the underlying mechanisms of CLEC4M in the immune microenvironment of NSCLC.

Methods

Integrating publicly accessible data and clinical tissue samples to verify the expression of CLEC4M in NSCLC. The diagnostic value of CLEC4M was determined by receiver operating characteristic (ROC) curve. Kaplan-Meier survival analysis, nomogram plot, univariate and multivariate Cox regression models were performed to evaluate the prognostic impact of CLEC4M on NSCLC patients. The correlation between CLEC4M and tumor immune infiltration was estimated using TIMER and UALCAN databases. Functional assessments including GO, KEGG pathway and GSEA analyses were implemented to illustrate the potential mechanisms of CLEC4M in NSCLC.

Results

CLEC4M was significantly downregulated in NSCLC tissue, as confirmed by immunohistochemistry of clinical tissues. The high AUC value of ROC curves demonstrated the diagnostic accuracy of CLEC4M in NSCLC. Additionally, low CLEC4M expression was associated with poor survival in NSCLC patients. Furthermore, CLEC4M was found to be significantly associated with tumor immune infiltration, and CLEC4M may be involved in immune activation and proliferation inhibition through the functional assessment, suggesting that CLEC4M may be a therapeutic target for NSCLC patients.

Conclusion

Our findings reveal CLEC4M is significantly downregulated in NSCLC tissues, and illustrate the diagnostic and prognostic value of CLEC4M in NSCLC, as well as its potential serve as an immune-related therapeutic target.

Neutrophil-inspired photothermo-responsive drug delivery system for targeted treatment of bacterial infection and endotoxins neutralization

BACKGROUND

P. aeruginosa, a highly virulent Gram-negative bacterium, can cause severe nosocomial infections, and it has developed resistance against most antibiotics. New therapeutic strategies are urgently needed to treat such bacterial infection and reduce its toxicity caused by endotoxin (lipopolysaccharide, LPS). Neutrophils have been proven to be able to target inflammation site and neutrophil membrane receptors such as Toll-like receptor-4 (TLR4) and CD14, and exhibit specific affinity to LPS. However, antibacterial delivery system based on the unique properties of neutrophils has not been reported.

METHODS

A neutrophil-inspired antibacterial delivery system for targeted photothermal treatment, stimuli-responsive antibiotic release and endotoxin neutralization is reported in this study. Specifically, the photothermal reagent indocyanine green (ICG) and antibiotic rifampicin (RIF) are co-loaded into poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP-ICG/RIF), followed by coating with neutrophil membrane to obtain antibacterial delivery system (NM-NP-ICG/RIF). The inflammation targeting properties, synergistic antibacterial activity of photothermal therapy and antibiotic treatment, and endotoxin neutralization have been studied in vitro. A P. aeruginosa-induced murine skin abscess infection model has been used to evaluate the therapeutic efficacy of the NM-NP-ICG/RIF.

RESULTS

Once irradiated by near-infrared lasers, the heat generated by NP-ICG/RIF triggers the release of RIF and ICG, resulting in a synergistic chemo-photothermal antibacterial effect against P. aeruginosa (~ 99.99% killing efficiency in 5 min). After coating with neutrophil-like cell membrane vesicles (NMVs), the nanoparticles (NM-NP-ICG/RIF) specifically bind to inflammatory vascular endothelial cells in infectious site, endowing the nanoparticles with an infection microenvironment targeting function to enhance retention time. Importantly, it is discovered for the first time that NMVs-coated nanoparticles are able to neutralize endotoxins. The P. aeruginosa murine skin abscess infection model further demonstrates the in vivo therapeutic efficacy of NM-NP-ICG/RIF.

CONCLUSION

The neutrophil-inspired antibacterial delivery system (NM-NP-ICG/RIF) is capable of targeting infection microenvironment, neutralizing endotoxin, and eradicating bacteria through a synergistic effect of photothermal therapy and antibiotic treatment. This drug delivery system made from FDA-approved compounds provides a promising approach to fighting against hard-to-treat bacterial infections.

Neutrophil extracellular traps formed during chemotherapy confer treatment resistance via TGF-β activation

Metastasis is the major cause of cancer death, and the development of therapy resistance is common. The tumor microenvironment can confer chemotherapy resistance (chemoresistance), but little is known about how specific host cells influence therapy outcome. We show that chemotherapy induces neutrophil recruitment and neutrophil extracellular trap (NET) formation, which reduces therapy response in mouse models of breast cancer lung metastasis. We reveal that chemotherapy-treated cancer cells secrete IL-1β, which in turn triggers NET formation. Two NET-associated proteins are required to induce chemoresistance: integrin-αvβ1, which traps latent TGF-β, and matrix metalloproteinase 9, which cleaves and activates the trapped latent TGF-β. TGF-β activation causes cancer cells to undergo epithelial-to-mesenchymal transition and correlates with chemoresistance. Our work demonstrates that NETs regulate the activities of neighboring cells by trapping and activating cytokines and suggests that chemoresistance in the metastatic setting can be reduced or prevented by targeting the IL-1β-NET-TGF-β axis.

Simiao Yong'an decoction ameliorates murine collagen-induced arthritis by modulating neutrophil activities: An in vitro and in vivo study

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a common systemic autoimmune disease with high morbidity and disability rate. Currently, there is no effective allopathic treatment for RA, and most of the drugs provoke many adverse effects. Simiao Yong'an decoction (SMYAD) is a traditional Chinese prescription for the treatment of sore and gangrene caused by hot poison. With the development of pharmacology and clinical research, SMYAD has remarkable anti-inflammatory properties and has been used for RA treatments for years.

AIM OF THE STUDY

This study aimed to investigate the anti-arthritic effect of SMYAD and further explore the immunopharmacological mechanisms.

MATERIALS AND METHODS

Arthritis was induced in DBA/1 mice by two-time immunizations. Collagen-induced rheumatoid arthritis (CIA) mice were divided into 4 groups: control, model, methotrexate (MTX), and SMYAD group (n = 6). The administration groups were given MTX (0.5 mg/kg/3 d) and SMYAD (4.5 g/kg/d) by gavage from day 14. The arthritis index (AI) score was evaluated every 3 days after the second immunization. Hematoxylin and eosin (H&E) staining, Safranin-O fast green staining, Trap staining, and Micro-CT were used to measure the histopathology injuries and bone destruction of joints. Granulocyte changes in the spleen, bone marrow, and period blood were analyzed by flow cytometry. The expression of inflammatory cytokines and chemokines in joints were detected by qRT-PCR. SMYAD-containing serum was obtained from SD rats gavaged with SMYAD. Neutrophils were isolated from peripheral blood and bone marrow for the in vitro experiments of transwell cell assay, apoptosis assay, reactive oxygen species (ROS) generation and neutrophil extracellular traps (NETs) formation.

RESULTS

SMYAD significantly relieved arthritis severity in CIA mice. The AI score was significantly decreased in the SMYAD group compared with the model group. Additionally, SMYAD alleviated inflammatory infiltration, cartilage damage, osteoclast formation, and bone damage in the ankle joints. In the flow cytometry assay, SMYAD significantly reduced granulocytes number in the spleen and bone marrow, while increased in peripheral blood. Furthermore, compared with the CIA group, SMYAD suppressed the mRNA levels of inflammatory factors including TNF-α, IL-1β, IL-6 and chemokines CXCL1, CXCL2, and IL-8 in the inflamed joints. In the in vitro studies, 20% SMYAD-containing serum effectively inhibited the migration of neutrophils, promoted neutrophils apoptosis, reduced ROS production and NETs formation.

CONCLUSION

Collectively, our results demonstrated that SMYAD effectively restrained arthritis in CIA mice by modulating neutrophil activities.

Progress in nanoparticle-based regulation of immune cells

Immune cells are indispensable defenders of the human body, clearing exogenous pathogens and toxicities or endogenous malignant and aging cells. Immune cell dysfunction can cause an inability to recognize, react, and remove these hazards, resulting in cancers, inflammatory diseases, autoimmune diseases, and infections. Immune cells regulation has shown great promise in treating disease, and immune agonists are usually used to treat cancers and infections caused by immune suppression. In contrast, immunosuppressants are used to treat inflammatory and autoimmune diseases. However, the key to maintaining health is to restore balance to the immune system, as excessive activation or inhibition of immune cells is a common complication of immunotherapy. Nanoparticles are efficient drug delivery systems widely used to deliver small molecule inhibitors, nucleic acid, and proteins. Using nanoparticles for the targeted delivery of drugs to immune cells provides opportunities to regulate immune cell function. In this review, we summarize the current progress of nanoparticle-based strategies for regulating immune function and discuss the prospects of future nanoparticle design to improve immunotherapy.

Neutrophils in Health and Disease: From Receptor Sensing to Inflammasome Activation

Neutrophils—polymorphonuclear cells (PMNs) are the cells of the initial immune response and make up the majority of leukocytes in the peripheral blood. After activation, these cells modify their functional status to meet the needs at the site of action or according to the agent causing injury. They receive signals from their surroundings and “plan” the course of the response in both temporal and spatial contexts. PMNs dispose of intracellular signaling pathways that allow them to perform a wide range of functions associated with the development of inflammatory processes. In addition to these cells, some protein complexes, known as inflammasomes, also have a special role in the development and maintenance of inflammation. These complexes participate in the proteolytic activation of key pro-inflammatory cytokines, such as IL-1β and IL-18. In recent years, there has been significant progress in the understanding of the structure and molecular mechanisms behind the activation of inflammasomes and their participation in the pathogenesis of numerous diseases. The available reports focus primarily on macrophages and dendritic cells. According to the literature, the activation of inflammasomes in neutrophils and the associated death type—pyroptosis—is regulated in a different manner than in other cells. The present work is a review of the latest reports concerning the course of inflammasome activation and inflammatory cytokine secretion in response to pathogens in neutrophils, as well as the role of these mechanisms in the pathogenesis of selected diseases.

S100A8/S100A9 Integrates F-Actin and Microtubule Dynamics to Prevent Uncontrolled Extravasation of Leukocytes

Immune reactions are characterized by the rapid immigration of phagocytes into sites of inflammation. Meticulous regulation of these migratory processes is crucial for preventing uncontrolled and harmful phagocyte extravasation. S100A8/S100A9 is the major calcium-binding protein complex expressed in phagocytes. After release, this complex acts as a proinflammatory alarmin in the extracellular space, but the intracellular functions of these highly abundant proteins are less clear. Results of this study reveal an important role of S100A8/S100A9 in coordinated cytoskeleton rearrangement during migration. We found that S100A8/S100A9 was able to cross-link F-actin and microtubules in a calcium- and phosphorylation-dependent manner. Cells deficient in S100A8/S100A9 showed abnormalities in cell adhesion and motility. Missing cytoskeletal interactions of S100A8/S100A9 caused differences in the surface expression and activation of β1-integrins as well as in the regulation of Src/Syk kinase family members. Loss of S100A8/S100A9 led to dysregulated integrin-mediated adhesion and migration, resulting in an overall higher dynamic activity of non-activated S100A8/S100A9-deficient phagocytes. Our data suggest that intracellular S100A8/S100A9 is part of a novel regulatory mechanism that ensures the precise control necessary to facilitate the change between the quiescent and activated state of phagocytes.

An Immunological Perspective on the Mechanism of Drug Induced Liver Injury: Focused on Drugs for Treatment of Hepatocellular Carcinoma and Liver Transplantation

The liver is frequently exposed to potentially toxic materials, and it is the primary site of clearance of foreign agents, along with many innate and adaptive immune cells. Subsequently, drug induced liver injury (DILI), which is caused by medications, herbs, and dietary supplements, often occurs and has become an important issue in liver diseases. Reactive metabolites or drug-protein complexes induce DILI via the activation of various innate and adaptive immune cells. There has been a revolutionary development of treatment drugs for hepatocellular carcinoma (HCC) and liver transplantation (LT), including immune checkpoint inhibitors (ICIs), that show high efficacy in patients with advanced HCC. Along with the high efficacy of novel drugs, DILI has become a pivotal issue in the use of new drugs, including ICIs. This review demonstrates the immunological mechanism of DILI, including the innate and adaptive immune systems. Moreover, it aims to provide drug treatment targets, describe the mechanisms of DILI, and detail the management of DILI caused by drugs for HCC and LT.

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

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

Neutrophils are gatekeepers of mucosal immunity

Mucosal tissues are constantly exposed to the outside environment. They receive signals from the commensal microbiome and tissue-specific triggers including alimentary and airborne elements and are tasked to maintain balance in the absence of inflammation and infection. Here, we present neutrophils as sentinel cells in mucosal immunity. We discuss the roles of neutrophils in mucosal homeostasis and overview clinical susceptibilities in patients with neutrophil defects. Finally, we present concepts related to specification of neutrophil responses within specific mucosal tissue microenvironments.

Development and characterization of trans-anethole-containing solid lipid microparticles: antiinflammatory and gastroprotective effects in experimental inflammation

The present study prepared, optimized, and characterized solid lipid microparticles that contained trans-anethole (SLMAN), evaluated their antiinflammatory activity in acute and chronic inflammation models, and investigated their effects on the gastric mucosa in arthritic rats. The microparticles were obtained by a hot homogenization process and characterized by physicochemical analyses. The acute inflammatory response was induced by an intradermal injection of 0.1 ml of carrageenan solution (200 μg) in the hind paw. The rats were treated orally with a single dose of SLMAN 1 h before induction of the inflammatory response. The chronic inflammatory response was induced by the subcutaneous application of 0.1 ml of complete Freund's adjuvant suspension (500 µg) in the hind paw. SLMAN was orally administered, starting on the day of arthritis induction, and continued for 21 days. The results showed that SLMAN was obtained with good encapsulation efficiency. Treatment with SLMAN at doses of 25 and 50 mg/kg was as effective as trans-anethole (AN) at a dose of 250 mg/kg on acute and chronic inflammatory responses. Histological analyses showed that treatment with SLMAN did not aggravate lesions in the gastric mucosa in arthritic rats. These results indicated that treatment with SLMAN at a dose that was 5-10 times lower than non-encapsulated AN exerted an inhibitory effect on acute and chronic inflammatory responses, suggesting the better bioavailability and efficacy of microencapsulated AN without aggravating lesions in the gastric mucosa in arthritic rats.

A20 and the noncanonical NF-κB pathway are key regulators of neutrophil recruitment during fetal ontogeny

Newborns are at high risk of developing neonatal sepsis, particularly if born prematurely. This has been linked to divergent requirements the immune system has to fulfill during intrauterine compared with extrauterine life. By transcriptomic analysis of fetal and adult neutrophils, we shed new light on the molecular mechanisms of neutrophil maturation and functional adaption during fetal ontogeny. We identified an accumulation of differentially regulated genes within the noncanonical NF-κB signaling pathway accompanied by constitutive nuclear localization of RelB and increased surface expression of TNF receptor type II in fetal neutrophils, as well as elevated levels of lymphotoxin α in fetal serum. Furthermore, we found strong upregulation of the negative inflammatory regulator A20 (Tnfaip3) in fetal neutrophils, which was accompanied by pronounced downregulation of the canonical NF-κB pathway. Functionally, overexpressing A20 in Hoxb8 cells led to reduced adhesion of these neutrophil-like cells in a flow chamber system. Conversely, mice with a neutrophil-specific A20 deletion displayed increased inflammation in vivo. Taken together, we have uncovered constitutive activation of the noncanonical NF-κB pathway with concomitant upregulation of A20 in fetal neutrophils. This offers perfect adaption of neutrophil function during intrauterine fetal life but also restricts appropriate immune responses particularly in prematurely born infants.

Beyond lymphopenia, unraveling radiation-induced leucocyte subpopulation kinetics and mechanisms through modeling approaches

Leucocyte subpopulations in both lymphoid and myeloid lineages have a significant impact on antitumor immune response. While radiation-induced lymphopenia is being studied extensively, radiation effects on lymphoid and myeloid subtypes have been relatively less addressed. Interactions between leucocyte subpopulations, their specific radiation sensitivity and the specific kinetics of each subpopulation can be modeled based on both experimental data and knowledge of physiological leucocyte depletion, production, proliferation, maturation and homeostasis. Modeling approaches of the leucocyte kinetics that may be used to unravel mechanisms underlying radiation induced-leucopenia and prediction of changes in cell counts and compositions after irradiation are presented in this review. The approaches described open up new possibilities for determining the influence of irradiation parameters both on a single-time point of acute effects and the subsequent recovery of leukocyte subpopulations. Utilization of these approaches to model kinetic data in post-radiotherapy states may be a useful tool for further development of new treatment strategies or for the combination of radiotherapy and immunotherapy.

The Role of Neutrophils in Spondyloarthritis: A Journey across the Spectrum of Disease Manifestations

Spondyloarthritis (SpA) contemplates the inflammatory involvement of the musculoskeletal system, gut, skin, and eyes, delineating heterogeneous diseases with a common pathogenetic background. In the framework of innate and adaptive immune disruption in SpA, neutrophils are arising, across different clinical domains, as pivotal cells crucial in orchestrating the pro-inflammatory response, both at systemic and tissue levels. It has been suggested they act as key players along multiple stages of disease trajectory fueling type 3 immunity, with a significant impact in the initiation and amplification of inflammation as well as in structural damage occurrence, typical of long-standing disease. The aim of our review is to focus on neutrophils' role within the spectrum of SpA, dissecting their functions and abnormalities in each of the relevant disease domains to understand their rising appeal as potential biomarkers and therapeutic targets.

Stromal Interaction Molecule 1 (STIM1) is a Potential Prognostic Biomarker and Correlates with Immune Infiltrates in Solid Tumors

Increasing evidence has shown that stromal interaction molecule 1 (STIM1), a key subunit of store-operated Ca2+ entry (SOCE), is closely associated with tumor growth, development, and metastasis. However, there is no report of a comprehensive assessment of STIM1 in pan-cancer. This study aimed to perform a general analysis of STIM1 in human tumors, including its molecular characteristics, functional mechanisms, clinical significance, and immune infiltrates correlation based on pan-cancer data from The Cancer Genome Atlas (TCGA). Gene expression analysis was investigated using TCGA RNA-seq data, the Tumor Immune Estimation Resource (TIMER). Phosphorylation analysis was undertaken using the Clinical Proteomic Tumor Analysis Consortium (CP-TAC) and the PhosphoNET database. Genetic alterations of STIM1 were analyzed using cBioPortal. Prognostic analysis was via the R package "survival" function and the Kaplan-Meier plotter. Functional enrichment analysis was via by the R package "cluster Profiler" function. The association between STIM1 and tumor-infiltrating immune cells and immune markers was by the R package "GSVA" function and TIMER. STIM1 was differentially expressed and associated with distinct clinical stages in multiple tumors. The phosphorylation of STIM1 at S673 is highly expressed in clear cell renal carcinoma and lung adenocarcinoma tumors compared to normal tissues. STIM1 genetic alterations correlate with poor prognosis in several tumors, including ovarian cancer and lung squamous cell carcinomas. High STIM1 expression is associated with good or poor prognosis across diverse tumors. Overall survival (OS) analysis indicated that STIM1 is a favorable prognostic factor for patients with BRCA, KIRC, LIHC, LUAD, OV, SARC, and UCEC, and is a risk prognostic factor for BLCA, KIRP, STAD, and UVM. There is a close correlation between STIM1 expression and immune cell infiltration, immune-regulated genes, chemokines, and immune checkpoints in a variety of tumors. STIM1 functions differently in diverse tumors, playing an oncogenic or antitumor role. Moreover, It may serve as a prognostic biomarker and an immunotherapy target across multiple tumors.