Neutrophil: A Cell with Many Roles in Inflammation or Several Cell Types?

From virus to inflammation, how influenza promotes lung damage

Despite seasonal vaccines, influenza-related hospitalization and death rates have remained unchanged over the past 5 years. Influenza pathogenesis has 2 crucial clinical components; first, influenza causes acute lung injury that may require hospitalization. Second, acute injury promotes secondary bacterial pneumonia, a leading cause of hospitalization and disease burden in the United States and globally. Therefore, developing an effective therapeutic regimen against influenza requires a comprehensive understanding of the damage-associated immune-mechanisms to identify therapeutic targets for interventions to mitigate inflammation/tissue-damage, improve antiviral immunity, and prevent influenza-associated secondary bacterial diseases. In this review, the pathogenic immune mechanisms implicated in acute lung injury and the possibility of using lung inflammation and barrier crosstalk for developing therapeutics against influenza are highlighted.

Eosinophils and Neutrophils-Molecular Differences Revealed by Spontaneous Raman, CARS and Fluorescence Microscopy

Leukocytes are a part of the immune system that plays an important role in the host’s defense against viral, bacterial, and fungal infections. Among the human leukocytes, two granulocytes, neutrophils (Ne) and eosinophils (EOS) play an important role in the innate immune system. For that purpose, eosinophils and neutrophils contain specific granules containing protoporphyrin-type proteins such as eosinophil peroxidase (EPO) and myeloperoxidase (MPO), respectively, which contribute directly to their anti-infection activity. Since both proteins are structurally and functionally different, they could potentially be a marker of both cells’ types. To prove this hypothesis, UV−Vis absorption spectroscopy and Raman imaging were applied to analyze EPO and MPO and their content in leukocytes isolated from the whole blood. Moreover, leukocytes can contain lipidic structures, called lipid bodies (LBs), which are linked to the regulation of immune responses and are considered to be a marker of cell inflammation. In this work, we showed how to determine the number of LBs in two types of granulocytes, EOS and Ne, using fluorescence and coherent anti-Stokes Raman scattering (CARS) microscopy. Spectroscopic differences of EPO and MPO can be used to identify these cells in blood samples, while the detection of LBs can indicate the cell inflammation process.

A molecular basis for the anti-inflammatory and anti-fibrosis properties of cannabidiol

Cannabidiol (CBD) is considered a non-psychoactive, antioxidant, and anti-inflammatory compound derived from the Cannabis sativa plant. There are various reports on the versatile function of CBD, including ameliorating chronic inflammation and fibrosis formation in several tissue types. However, only a hand full of studies have proposed or provided a molecular justification for the beneficial properties of this Phyto-compound. This review focused on the anti-inflammation and anti-fibrotic effects of CBD based on modulating the associated chemokines/cytokines and receptor-mediated pathways. We also highlighted the regulatory impact of CBD on reactive oxygen species (ROS) producing-NADPH oxidase (Nox), and ROS scavenging-superoxide dismutase (SOD) enzymes. Although CBD has a low affinity to Cannabinoid receptors 1 and 2 (CB₁ and CB₂ ), we reported on the activation of these receptors by other CBD analogs, and CBD on non-CBD receptors. CBD downregulates pro-inflammatory and pro-fibrotic chemokines/cytokines by acting as direct or indirect agonists of Adenosine A_2A /equilibrative nucleoside transporter receptors, Peroxisome proliferator-activated receptor gamma, and Transient receptor potential vanilloid receptors or channels, and as an antagonist of GPR55 receptors. CBD also caused the reduction and enhancement of the ROS producing, Nox and ROS-scavenging, SOD enzyme activities, respectively. This review thus recommends the continued study of CBD's molecular mechanism in treating established and emerging inflammatory and fibrosis-related diseases.

Neutrophil interactions with the sexually transmitted parasite Trichomonas vaginalis: implications for immunity and pathogenesis

Trichomoniasis is the third most common sexually transmitted infection in humans and is caused by the protozoan parasite, Trichomonas vaginalis (Tv). Pathogenic outcomes are more common in women and generally include mild vaginitis or cervicitis. However, more serious effects associated with trichomoniasis include adverse reproductive outcomes. Like other infectious agents, pathogenesis from Tv infection is predicted to be the result of both parasite and host factors. At the site of infection, neutrophils are the most abundant immune cells present and probably play key roles in both parasite clearance and inflammatory pathology. Here, we discuss the evidence that neutrophils home to the site of Tv infection, kill the parasite, and that in some circumstances, parasites possibly evade neutrophil-directed killing. In vitro, the parasite is killed by neutrophils using a novel antimicrobial mechanism called trogocytosis, which probably involves both innate and adaptive immunity. While mechanisms of evasion are mostly conjecture at present, the persistence of Tv infections in patients argues strongly for their existence. Additionally, many strains of Tv harbour microbial symbionts Mycoplasma hominis or Trichomonasvirus, which are both predicted to impact neutrophil responses against the parasite. Novel research tools, especially animal models, will help to reveal the true outcomes of many factors involved in neutrophil-Tv interactions during trichomoniasis.

Characterization of the Impact of Oncolytic Vesicular Stomatitis Virus on the Trafficking, Phenotype, and Antigen Presentation Potential of Neutrophils and Their Ability to Acquire a Non-Structural Viral Protein

Neutrophils are innate leukocytes that mount a rapid response to invading pathogens and sites of inflammation. Although neutrophils were traditionally considered responders to bacterial infections, recent advances have demonstrated that they are interconnected with both viral infections and cancers. One promising treatment strategy for cancers is to administer an oncolytic virus to activate the immune system and directly lyse cancerous cells. A detailed characterization of how the innate immune system responds to a viral-based therapy is paramount in identifying its systemic effects. This study analyzed how administering the rhabdovirus vesicular stomatitis virus (VSV) intravenously at 1 × 10⁹ PFU acutely influenced neutrophil populations. Bone marrow, blood, lungs, and spleen were acquired three- and 24-h after administration of VSV for analysis of neutrophils by flow cytometry. Infection with VSV caused neutrophils to rapidly egress from the bone marrow and accumulate in the lungs. A dramatic increase in immature neutrophils was observed in the lungs, as was an increase in the antigen presentation potential of these cells within the spleen. Furthermore, the potential for neutrophils to acquire viral transgene-encoded proteins was monitored using a variant of VSV that expressed enhanced green fluorescent protein (GFP). If an in vitro population of splenocytes were exposed to αCD3 and αCD28, a substantial proportion of the neutrophils would become GFP-positive. This suggested that the neutrophils could either acquire more virus-encoded antigens from infected splenocytes or were being directly infected. Five different dosing regimens were tested in mice, and it was determined that a single dose of VSV or two doses of VSV administered at a 24-h interval, resulted in a substantial proportion of neutrophils in the bone marrow becoming GFP-positive. This correlated with a decrease in the number of splenic neutrophils. Two doses administered at intervals longer than 24-h did not have these effects, suggesting that neutrophils became resistant to antigen uptake or direct infection with VSV beyond 24-h of activation. These findings implicated neutrophils as major contributors to oncolytic rhabdoviral therapies. They also provide several clear future directions for research and suggest that neutrophils should be carefully monitored during the development of all oncolytic virus-based treatment regimens.

Recent Advances in Nanocarrier-Assisted Therapeutics Delivery Systems

Nanotechnologies have attracted increasing attention in their application in medicine, especially in the development of new drug delivery systems. With the help of nano-sized carriers, drugs can reach specific diseased areas, prolonging therapeutic efficacy while decreasing undesired side-effects. In addition, recent nanotechnological advances, such as surface stabilization and stimuli-responsive functionalization have also significantly improved the targeting capacity and therapeutic efficacy of the nanocarrier assisted drug delivery system. In this review, we evaluate recent advances in the development of different nanocarriers and their applications in therapeutics delivery.

An inflammatory vascular endothelium-mimicking microfluidic device to enable leukocyte rolling and adhesion for rapid infection diagnosis

Recruitment of circulating leukocytes to sites of infection is of utmost importance in the development, propagation, and outcome of sepsis. These multi-step processes are mediated by interactions between adhesion receptors of leukocytes and cell adhesion molecules (CAMs) of endothelial cells, such as P-selectin, E-selectin and ICAM-1. However, the potential utility of the CAMs-facilitated leukocyte capture has not been thoroughly investigated as an index of the host response to infection for diagnostic purposes. Here, we report that the systemic infection affects the expression of CAMs ligands on leukocytes, upregulating the expression of P-selectin ligand-1 (PSGL-1) and increasing the number of PSGL-1- and E-selectin ligand-1 (ESL-1)-expressing leukocyte levels in septic blood. We leveraged this finding to determine infection by measuring the increased adhesion of leukocytes to an inflammatory vascular endothelium-mimicking microchannel coated with CAMs. We successfully validated that the proposed method can significantly differentiate infection in bacteremia and endotoxemia models in rats as early as an hour post-infection using a finger-prick volume of blood (50 μL), which were unachievable with the conventional diagnostic methods.

Neuroimmune Mechanisms in Signaling of Pain During Acute Kidney Injury (AKI)

Acute kidney injury (AKI) is a significant global health concern. The primary causes of AKI include ischemia, sepsis and nephrotoxicity. The unraveled interface between nervous system and immune response with specific focus on pain pathways is generating a huge interest in reference to AKI. The nervous system though static executes functions by nerve fibers throughout the body. Neuronal peptides released by nerves effect the immune response to mediate the hemodynamic system critical to the functioning of kidney. Pain is the outcome of cellular cross talk between nervous and immune systems. The widespread release of neuropeptides, neurotransmitters and immune cells contribute to bidirectional neuroimmune cross talks for pain manifestation. Recently, we have reported pain pathway genes that may pave the way to better understand such processes during AKI. An auxiliary understanding of the functions and communications in these systems will lead to novel approaches in pain management and treatment through the pathological state, specifically during acute kidney injury.

Structural and functional diversity of neutrophil glycosylation in innate immunity and related disorders

The granulated neutrophils are abundant innate immune cells that utilize bioactive glycoproteins packed in cytosolic granules to fight pathogenic infections, but the neutrophil glycobiology remains poorly understood. Facilitated by technological advances in glycoimmunology, systems glycobiology and glycoanalytics, a considerable body of literature reporting on novel aspects of neutrophil glycosylation has accumulated. Herein, we summarize the building knowledge of the structural and functional diversity displayed by N- and O-linked glycoproteins spatiotemporally expressed and sequentially brought-into-action across the diverse neutrophil life stages during bone marrow maturation, movements to, from and within the blood circulation and microbicidal processes at the inflammatory sites in peripheral tissues. It transpires that neutrophils abundantly decorate their granule glycoproteins including neutrophil elastase, myeloperoxidase and cathepsin G with peculiar glyco-signatures not commonly reported in other areas of human glycobiology such as hyper-truncated chitobiose core- and paucimannosidic-type N-glycans and monoantennary complex-type N-glycans. Sialyl Lewis^x, Lewis^x, poly-N-acetyllactosamine extensions and core 1-/2-type O-glycans are also common neutrophil glyco-signatures. Granule-specific glycosylation is another fascinating yet not fully understood feature of neutrophils. Recent literature suggests that unconventional biosynthetic pathways and functions underpin these prominent neutrophil-associated glyco-phenotypes. The impact of glycosylation on key neutrophil effector functions including extravasation, degranulation, phagocytosis and formation of neutrophil extracellular traps during normal physiological conditions and in innate immune-related diseases is discussed. We also highlight new technologies that are expected to further advance neutrophil glycobiology and briefly discuss the untapped diagnostic and therapeutic potential of neutrophil glycosylation that could open avenues to combat the increasingly prevalent innate immune disorders.

Immunological distinctions between nonalcoholic steatohepatitis and hepatocellular carcinoma

Nonalcoholic fatty liver disease (NAFLD), the most common cause of chronic liver disease, ranges from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH), which is a more aggressive form characterized by hepatocyte injury, inflammation, and fibrosis. Increasing evidence suggests that NASH is a risk factor for hepatocellular carcinoma (HCC), which is the fifth most common cancer worldwide and the second most common cause of cancer-related death. Recent studies support a strong mechanistic link between the NASH microenvironment and HCC development. The liver has a large capacity to remove circulating pathogens and gut-derived microbial compounds. Thus, the liver is a central player in immunoregulation. Altered immune responses are tightly associated with the development of NASH and HCC. The objective of this study was to differentiate the roles of specific immune cell subsets in NASH and HCC pathogenesis.

Clarifying the role of specific cells in the immune system in the transition from non-alcoholic fatty liver disease (NAFLD) to liver cancer will help to understand disease progression and may open avenues towards new preventive and therapeutic strategies. NAFLD is the most common chronic liver disease. Growing evidence suggests that its most aggressive form, non-alcoholic steatohepatitis (NASH), can promote the development of liver cancer, the second most common cause of cancer deaths worldwide. Chang-Woo Lee and colleagues at Sungkyunkwan University, Suwon, South Korea review the immunological distinction between NASH and liver cancer, focusing on the levels and activities of six key types of immune system cells. Chronic inflammation mediated by the immune system can create conditions for NAFLD, NASH and liver cancer to develop and worsen.

Aedes Mosquito Salivary Components and Their Effect on the Immune Response to Arboviruses

Vector-borne diseases are responsible for over a billion infections each year and nearly one million deaths. Mosquito-borne dengue virus, West Nile, Japanese encephalitis, Zika, Chikungunya, and Rift Valley Fever viruses constitute major public health problems in regions with high densities of arthropod vectors. During the initial step of the transmission cycle, vector, host, and virus converge at the bite site, where local immune cells interact with the vector's saliva. Hematophagous mosquito saliva is a mixture of bioactive components known to modulate vertebrate hemostasis, immunity, and inflammation during the insect's feeding process. The capacity of mosquito saliva to modulate the host immune response has been well-studied over the last few decades and has led to the consensus that the presence of saliva is linked to the enhancement of virus transmission, host susceptibility, disease progression, viremia levels, and mortality. We review some of the major aspects of the interactions between mosquito saliva and the host immune response that may be useful for future studies on the control of arboviruses.

Granulozytentransfusion: Update 2020

Die therapeutische Anwendung von Granulozytenkonzentraten erfolgt im klinischen Alltag im Gegensatz zu der anderer Blutprodukte nur selten und unregelmäßig. Der zurückhaltende Einsatz beruht unter anderem auf dem Fehlen einer breiten Evidenz, logistischen und wirtschaftlichen Problemen und dem Vorhandensein anderer potenter Therapieoptionen neutropener Infektionen. Dennoch gab es in den letzten Jahren neue wissenschaftliche Erkenntnisse nicht nur zu Physiologie und Pathophysiologie der Granulozyten, wie neu charakterisierten zellulären Verteidigungsstrategien oder deren Mitwirkung bei thrombotischen oder malignen Ereignissen, sondern auch zu deren therapeutischem Effekt. Dieser wird von einer Vielzahl an Parametern, wie der Art der Infektion, dem Transfusionszeitpunkt und der Dosis, beeinflusst. Das macht die Indikationsstellung zu einer komplexen Einzelfallentscheidung und es gilt, die heterogene Datenlage systematisch zusammenzufassen. Außerdem wurden die etablierten Indikationen neutropener bzw. neutropathischer Infektionen um experimentelle, mögliche neue Anwendungsgebiete wie die Mukositis oder Leukämiebehandlung erweitert. Die erfolgreiche Anwendung setzt eine geeignete, moderne Herstellungsweise voraus. Neben der Apherese, bei der eine relativ hohe Spenderbelastung unter anderem durch Nebenwirkungen von Mobilisationsregime und Sedimentationsbeschleunigern berücksichtigt werden muss, existieren weitere Verfahren wie die Gewinnung von Granulozyten aus Buffy Coats von Vollblutspenden. Diese versprechen eine Reduktion logistischer Probleme und unerwünschter Wirkungen auf den Spender. Unerwünschte Wirkungen bei Empfängern von Granulozytentransfusionen sollten nach wie vor berücksichtigt und gegen einen erhofften therapeutischen Effekt abgewogen werden.

Detection and Differentiation of Bacterial and Fungal Infection of Neutrophils from Peripheral Blood Using Raman Spectroscopy

Neutrophils are important cells of the innate immune system and the major leukocyte subpopulation in blood. They are responsible for recognizing and neutralizing invading pathogens, such as bacteria or fungi. For this, neutrophils are well equipped with pathogen recognizing receptors, cytokines, effector molecules, and granules filled with reactive oxygen species (ROS)-producing enzymes. Depending on the pathogen type, different reactions are triggered, which result in specific activation states of the neutrophils. Here, we aim to establish a label-free method to indirectly detect infections and to identify the cause of infection by spectroscopic characterization of the neutrophils. For this, isolated neutrophils from human peripheral blood were stimulated in an in vitro infection model with heat-inactivated Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial pathogens as well as with heat-inactivated and viable fungi (Candida albicans). Label-free and nondestructive Raman spectroscopy was used to characterize neutrophils on a single cell level. Phagocytized fungi could be visualized in a few high-resolution false color images of individual neutrophils using label-free Raman spectroscopic imaging. Using a high-throughput screening Raman spectroscope (HTS-RS), Raman spectra of more than 2000 individual neutrophils from three different donors were collected in each treatment group, yielding a data set of almost 20 000 neutrophil spectra. Random forest classification models were trained to differentiate infected and noninfected cells with high accuracy (90%). Among the neutrophils challenged with pathogens, even the cause of infection, bacterial or fungal, was predicted correctly with 92% accuracy. Therefore, Raman spectroscopy enables reliable neutrophil phenotyping and infection diagnosis in a label-free manner. In contrast to the microbiological diagnostic standard, where the pathogen is isolated in time-consuming cultivation, this Raman-based method could potentially be blood-culture independent, thus saving precious time in bloodstream infection diagnostics.

Multiple Roles for Chemokines in Neutrophil Biology

Chemokines are recognized as the most critical mediators for selective neutrophil recruitment during inflammatory conditions. Furthermore, they are considered fundamental regulators of neutrophil mobilization from the bone marrow (BM) to the bloodstream and for their homing back at the end of their life for apoptosis and clearance. However, chemokines are also important mediators of neutrophil effector functions including oxidative burst, degranulation, neutrophil extracellular trap (NET)osis, and production of inflammatory mediators. Neutrophils have been historically considered as a homogeneous population. In recent years, several maturation stages and subsets with different phenotypic profiles and effector functions were described both in physiological and pathological conditions such as infections, autoimmunity, and cancer. The aim of this review is to give an overview of the current evidence regarding the role of chemokines and chemokine receptors in neutrophil biology, including their possible role in neutrophil maturation, differentiation, and in defining emerging neutrophil subsets.

Cellular Senescence Promotes Skin Carcinogenesis through p38MAPK and p44/42MAPK Signaling

Cellular senescence entails an irreversible growth arrest that evolved in part to prevent cancer. Paradoxically, senescent cells secrete proinflammatory and growth-stimulatory molecules, termed the senescence-associated secretory phenotype (SASP), which is correlated with cancer cell proliferation in culture and xenograft models. However, at what tumor stage and how senescence and the SASP act on endogenous tumor growth in vivo is unknown. To understand the role of senescence in cancer etiology, we subjected p16-3MR transgenic mice, which permit the identification and selective elimination of senescent cells in vivo, to the well-established two-step protocol of squamous cell skin carcinoma, in which tumorigenesis is initiated by a carcinogen 7,12-dimethylbenz[α]anthracene, and then promoted by 12-O-tetradecanoyl-phorbol-13-acetate (TPA). We show that TPA promotes skin carcinogenesis by inducing senescence and a SASP. Systemic induction of senescence in nontumor-bearing p16-3MR mice using a chemotherapy followed by the two-step carcinogenesis protocol potentiated the conversion of benign papillomas to carcinomas by elevating p38MAPK and MAPK/ERK signaling. Ablation of senescent cells reduced p38MAPK and MAPK/ERK signaling, thereby preventing the progression of benign papillomas to carcinomas. Thus, we show for the first time that senescent cells are tumor promoters, not tumor initiators, and that they stimulate skin carcinogenesis by elevating p38MAPK and MAPK/ERK signaling. These findings pave the way for developing novel therapeutics against senescence-fueled cancers. SIGNIFICANCE: These findings identify chemotherapy-induced senescence as a culprit behind tumor promotion, suggesting that elimination of senescent cells after chemotherapy may reduce occurrence of second cancers decades later. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/17/3606/F1.large.jpg.

Fatty Acid Mediators in the Tumor Microenvironment

Patients with cancer frequently overexpress inflammatory cytokines with an associated neutrophilia both of which may be downregulated by diets with high omega-3 polyunsaturated fatty acids (ω-3 PUFA). The anti-inflammatory activity of dietary ω-3 PUFA has been suggested to have anticancer properties and to improve survival of cancer patients. Currently, the majority of dietary research efforts do not differentiate between obesity and dietary fatty acid consumption as mediators of inflammatory cell expansion and tumor microenvironmental infiltration, initiation, and progression. In this chapter, we discuss the relationships between dietary lipids, inflammation, neoplasia and strategies to regulate these relationships. We posit that dietary composition, notably the ratio of ω-3 vs. ω-6 PUFA, regulates tumor initiation and progression and the frequency and sites of metastasis that, together, impact overall survival (OS). We focus on three broad topics: first, the role of dietary lipids in chronic inflammation and tumor initiation, progression, and regression; second, lipid mediators linking inflammation and cancer; and third, dietary lipid regulation of murine and human tumor initiation, progression, and metastasis.

Circulating Neutrophils of Nonalcoholic Steatohepatitis Patients Show an Activated Phenotype and Suppress T Lymphocytes Activity

Neutrophils or PolyMorphonuclear Neutrophils (PMNs) are key effector cells of the innate immune system and thanks to their remarkable plasticity, establish a cross talk with T cells modulating their survival and effector functions. During Nonalcoholic Steatohepatitis (NASH), the advanced form of hepatic steatosis or NAFL, PMNs infiltrate liver tissue, becoming a histological feature of NASH. Our aim was to evaluate the frequency of PMNs in NAFL and NASH patients in order to understand how they modulate the activity of circulating CD4⁺ and CD8⁺ T cells. In our cohort of patients, NASH patients displayed a higher frequency of circulating PMNs that was strongly correlated to liver enzymes, grade of steatosis, inflammation and fibrosis, the hepatocellular ballooning, and NAFLD Activity Score (NAS). Furthermore, even if ex vivo, in both groups of patients, PMNs shared the same phenotype of resting cells, after 24 hours of coculture with autologous CD4+ and CD8+ T cells, PMNs of NASH patients acquired a more active phenotype, becoming able to strongly inhibit proliferation and activation of CD4⁺ and CD8⁺ T cells. The higher ability of PMNs of NASH patients in suppressing CD4⁺ and CD8⁺ T cells, over time, might contribute in reducing the immunological defense of liver tissue against damages thus taking part in the progression of the NAFL disease toward NASH.

Analysis of Biochemical Parameters in Children with Chronic Tonsillitis

Chronic tonsillitis are frequent in pediatric pathology with numerous involved risk factors and pathogenic mechanisms. In this study, epidemiological data and biochemical values addressed to inflammation and mineral, lipid and hepatic metabolism were analyzed for 37 children of school age with chronic tonsillitis. We found that in the majority of cases, chronic tonsillitis was associated with increasing number of blood circulating inflammatory cells, high values of transaminases, cholesterol, triglycerides and low values of procalcitonin, C-reactive protein, calcium, vitamin D and serum iron. The results indicated relations of the biochemical profile analyzed with risk factors and systemic mechanisms for initiation and maintenance of chronic tonsillitis, aspects that can be used to optimize the prognosis of chronic tonsillitis in children.

Epithelium-derived IL-33 activates mast cells to initiate neutrophil recruitment following corneal injury

PURPOSE

Neutrophils play a critical role in defending against threats such as microbial infection, yet their activation during innate immune response incites collateral damage to healthy tissues. We have previously shown that corneal injury induces mast cells to express the neutrophil chemoattractant CXCL2. Here we delineate the mechanism of injury-induced, non-IgE-mediated mast cell activation at the ocular surface.

METHODS

Corneal injury was induced by mechanical removal of the epithelium and anterior stroma in mast cell deficient (cKit^W-sh) and C57BL/6 mice using Algerbrush II. Corneas were analyzed for frequencies of total CD45⁺ inflammatory cells, CD11b⁺Ly6G⁺ neutrophils, and cKit⁺FcεR1⁺ mast cells using flow cytometry. Mast cells were stimulated with different inflammatory factors known to increase during corneal injury (IL-33, IL-1β, IL-36γ, IL-6, SDF1α and Substance P) and assessed for the secretion of β-hexosaminidase, tryptase and CXCL2 using ELISA. IL-33 neutralizing antibody (1 mg/ml) was administered locally for mast cell inhibition in vivo.

RESULTS

Mast cell deficient mice failed to recruit early neutrophils to the injured corneas. IL-33 stimulation upregulated CXCL2 secretion by mast cells. Corneal injury resulted in amplified expression of IL-33 at the cornea and epithelium was identified as its primary source. Topical neutralization of IL-33 at the ocular surface inhibited mast cell activation, limited neutrophil infiltration, and reduced corneal inflammatory haze, normalizing tissue architecture following ocular injury.

CONCLUSIONS

These data implicate IL-33 in mast cell activation and early neutrophil recruitment in non-allergic inflammation, suggesting IL-33 as a potential therapeutic target in inflammatory disorders of the ocular surface.

What Is the Evolutionary Fingerprint in Neutrophil Granulocytes?

Over the years of evolution, thousands of different animal species have evolved. All these species require an immune system to defend themselves against invading pathogens. Nevertheless, the immune systems of different species are obviously counteracting against the same pathogen with different efficiency. Therefore, the question arises if the process that was leading to the clades of vertebrates in the animal kingdom-namely mammals, birds, amphibians, reptiles, and fish-was also leading to different functions of immune cells. One cell type of the innate immune system that is transmigrating as first line of defense in infected tissue and counteracts against pathogens is the neutrophil granulocyte. During the host-pathogen interaction they can undergo phagocytosis, apoptosis, degranulation, and form neutrophil extracellular traps (NETs). In this review, we summarize a wide spectrum of information about neutrophils in humans and animals, with a focus on vertebrates. Special attention is kept on the development, morphology, composition, and functions of these cells, but also on dysfunctions and options for cell culture or storage.

LPS-mediated neutrophil VEGF-A release is modulated by cannabinoid receptor activation

Neutrophils (PMNs) are innate immune cells with primary roles in inflammation and in host defense against infections. Both inflammatory and tumor angiogenesis are modulated by a sequential, coordinated production of angiogenic factors such as vascular endothelial growth factors (VEGFs), angiopoietins, hepatocyte growth factor (HGF), and chemokines. These factors are produced by several immune cells, including PMNs. Activation of cannabinoid receptor type-1 (CB₁ ) and -2 (CB₂ ) has been suggested as a new strategy to modulate in vitro and in vivo angiogenesis. We sought to investigate whether activation of CB₁ and CB₂ by CB agonists modulate LPS-mediated angiogenic activity of human PMNs. Highly purified PMNs were isolated from buffy coats of healthy donors. Cells were stimulated with CB₁ and CB₂ agonists/antagonists alone and/or in combination with LPS. Angiogenic factors in cell-free supernatants were measured by ELISA. The modulation of activation markers of PMNs by CB agonists was evaluated by flow cytometry. Angiogenesis in vitro was measured as tube formation by optical microscopy. Endothelial cell permeability was assessed by an in vitro vascular permeability assay. LPS-activated PMNs released VEGF-A, CXCL8, and HGF. Preincubation of PMNs with low concentrations of CB₁ and CB₂ agonists inhibited VEGF-A release induced by LPS, but did not affect CXCL8 and HGF production. The effects of CB agonists on VEGF-A release induced by LPS were reversed by preincubation with CB antagonists. CB agonists modulated in vitro angiogenesis and endothelial permeability induced by supernatants of LPS-activated PMNs through the reduction of VEGF-A. Neutrophils play a central role in the control of bacterial infections and in the outcome of sepsis. The latter condition is associated with an increase in circulating levels of VEGF-A. We demonstrated that low concentrations of CB agonists inhibit VEGF-A release from LPS-activated PMNs. These results suggest that CB agonists might represent a novel therapeutic strategy in patients with sepsis.

Oleic and Linoleic Acids Induce the Release of Neutrophil Extracellular Traps via Pannexin 1-Dependent ATP Release and P2X1 Receptor Activation

Non-esterified fatty acids (NEFAs) such as oleic acid (OA) and linoleic acid (LA) are associated with a higher incidence of infectious diseases such as metritis and mastitis during the bovine peripartum. Fatty acids can induce an increase in the release of ATP, and changes in the expression levels of purinergic receptors in bovine polymorphonuclears (PMN) during peripartum have also been reported. PMN respond to inflammatory processes with production of ROS, release of proteolytic and bactericidal proteins, and formation of neutrophil extracellular traps (NETs). NETs formation is known to require ATP production through glycolysis. Studies have shown that the above-mentioned metabolic changes alter innate immune responses, particularly in PMN. We hypothesized that NEFAs induce the formation of NETs through ATP release by Pannexin 1 and activation of purinergic receptors. In this study, we found that OA and LA induce NET formation and extracellular ATP release. Carbenoxolone, a pannexin-1 (PANX1) inhibitor, reduced OA- and LA-induced ATP release. We also found that P2X1, P2X4, P2X5, P2X7, and PANX1 were expressed at the mRNA level in bovine PMN. Additionally, NEFA-induced NET formation was completely abolished with exposure to NF449, a P2X1 antagonist, and partially inhibited by treatment with etomoxir, an inhibitor of fatty acid oxidation (FAO). Our results suggest that OA and LA induce NET formation and ATP release via PANX1 and activation of P2X1. These new data contribute to explaining the effects of NEFA high concentrations during the transition period of dairy cattle and further understanding of pro-inflammatory effects and outcome of postpartum diseases.

Autologous apoptotic neutrophils inhibit inflammatory cytokine secretion by human dendritic cells, but enhance Th1 responses

Neutrophils represent the most abundant cell type in peripheral blood and exhibit a remarkably brief (6–8 h) half‐life in circulation. The fundamental role of these professional phagocytes has been established in acute inflammation, based on their potential to both initiate and receive inflammatory signals. Furthermore, neutrophils also take part in maintaining chronic inflammatory processes, such as in various autoimmune diseases. Here, we demonstrate that human autologous apoptotic neutrophils are readily engulfed by immature monocyte‐derived dendritic cells (moDCs) with similar efficiency as allogeneic apoptotic neutrophils [Majai G et al. (2010) J Leukoc Biol 88, 981–991]. Interestingly, in contrast to the allogeneic system, exposure of moDCs to autologous apoptotic neutrophils inhibits LPS + IFN‐γ‐induced production of inflammatory cytokines in a phagocytosis‐independent manner. Autologous apoptotic neutrophil‐primed DCs are able to modulate T‐cell responses by inducing the generation of IFN‐γ‐secreting cells while hampering that of IL‐17A‐producing cells. Our observations indicate that capture of autologous apoptotic neutrophils by immature DCs may impede further neutrophil‐mediated phagocytosis and tissue damage, and allow increased clearance of dying cells by macrophages.

Urinary proteomics links keratan sulfate degradation and lysosomal enzymes to early type 1 diabetes

Diabetes is the leading cause of end-stage renal disease worldwide. Our understanding of the early kidney response to chronic hyperglycemia remains incomplete. To address this, we first investigated the urinary proteomes of otherwise healthy youths with and without type 1 diabetes and subsequently examined the enriched pathways that might be dysregulated in early disease using systems biology approaches. This cross-sectional study included two separate cohorts for the discovery (N = 30) and internal validation (N = 30) of differentially excreted proteins. Discovery proteomics was performed on a Q Exactive Plus hybrid quadrupole-orbitrap mass spectrometer. We then searched the pathDIP, KEGG, and Reactome databases to identify enriched pathways in early diabetes; the Integrated Interactions Database to retrieve protein-protein interaction data; and the PubMed database to compare fold changes of our signature proteins with those published in similarly designed studies. Proteins were selected for internal validation based on pathway enrichment and availability of commercial enzyme-linked immunosorbent assay kits. Of the 2451 proteins identified, 576 were quantified in all samples from the discovery cohort; 34 comprised the urinary signature for early diabetes after Benjamini-Hochberg adjustment (Q < 0.05). The top pathways associated with this signature included lysosome, glycosaminoglycan degradation, and innate immune system (Q < 0.01). Notably, all enzymes involved in keratan sulfate degradation were significantly elevated in urines from youths with diabetes (|fold change| > 1.6). Increased urinary excretion of monocyte differentiation antigen CD14, hexosaminidase A, and lumican was also observed in the validation cohort (P < 0.05). Twenty-one proteins from our signature have been reported elsewhere as potential mediators of early diabetes. In this study, we identified a urinary proteomic signature for early type 1 diabetes, of which lysosomal enzymes were major constituents. Our findings highlight novel pathways such as keratan sulfate degradation in the early kidney response to hyperglycemia.

Y-RNA subtype ratios in plasma extracellular vesicles are cell type- specific and are candidate biomarkers for inflammatory diseases

Major efforts are made to characterize the presence of microRNA (miRNA) and messenger RNA in blood plasma to discover novel disease-associated biomarkers. MiRNAs in plasma are associated to several types of macromolecular structures, including extracellular vesicles (EV), lipoprotein particles (LPP) and ribonucleoprotein particles (RNP). RNAs in these complexes are recovered at variable efficiency by commonly used EV- and RNA isolation methods, which causes biases and inconsistencies in miRNA quantitation. Besides miRNAs, various other non-coding RNA species are contained in EV and present within the pool of plasma extracellular RNA. Members of the Y-RNA family have been detected in EV from various cell types and are among the most abundant non-coding RNA types in plasma. We previously showed that shuttling of full-length Y-RNA into EV released by immune cells is modulated by microbial stimulation. This indicated that Y-RNAs could contribute to the functional properties of EV in immune cell communication and that EV-associated Y-RNAs could have biomarker potential in immune-related diseases. Here, we investigated which macromolecular structures in plasma contain full length Y-RNA and whether the levels of three Y-RNA subtypes in plasma (Y1, Y3 and Y4) change during systemic inflammation. Our data indicate that the majority of full length Y-RNA in plasma is stably associated to EV. Moreover, we discovered that EV from different blood-related cell types contain cell-type-specific Y-RNA subtype ratios. Using a human model for systemic inflammation, we show that the neutrophil-specific Y4/Y3 ratios and PBMC-specific Y3/Y1 ratios were significantly altered after induction of inflammation. The plasma Y-RNA ratios strongly correlated with the number and type of immune cells during systemic inflammation. Cell-type-specific "Y-RNA signatures" in plasma EV can be determined without prior enrichment for EV, and may be further explored as simple and fast test for diagnosis of inflammatory responses or other immune-related diseases.

Imaging flow cytometry methods for quantitative analysis of label-free crystalline silica particle interactions with immune cells

Exposure to respirable fractions of crystalline silica quartz dust particles is associated with silicosis, cancer and the development of autoimmune conditions. Early cellular interactions are not well understood, partly due to a lack of suitable technological methods. Improved techniques are needed to better quantify and study high-level respirable crystalline silica exposure in human populations. Techniques that can be applied to complex biological matrices are pivotal to understanding particle-cell interactions and the impact of particles within real, biologically complex environments. In this study, we investigated whether imaging flow cytometry could be used to assess the interactions between cells and crystalline silica when present within complex biological matrices. Using the respirable-size fine quartz crystalline silica dust Min-u-sil® 5, we first validated previous reports that, whilst associating with cells, crystalline silica particles can be detected solely through their differential light scattering profile using conventional flow cytometry. This same property reliably identified crystalline silica in association with primary monocytic cells in vitro using an imaging flow cytometry assay, where darkfield intensity measurements were able to detect crystalline silica concentrations as low as 2.5 μg/mL. Finally, we ultilised fresh whole blood as an exemplary complex biological matrix to test the technique. Even after the increased sample processing required to analyse cells within whole blood, imaging flow cytometry was capable of detecting and assessing silica-association to cells. As expected, in fresh whole blood exposed to crystalline silica, neutrophils and cells of the monocyte/macrophage lineage phagocytosed the particles. In addition to the use of this technique in in vitro exposure models, this method has the potential to be applied directly to ex vivo diagnostic studies and research models, where the identification of crystalline silica association with cells in complex biological matrices such as bronchial lavage fluids, alongside additional functional and phenotypic cellular readouts, is required.

Propranolol Is an Effective Topical and Systemic Treatment Option for Experimental Epidermolysis Bullosa Acquisita

Propranolol is an ADRB2 blocker that regulates heart muscle contractions, smooth muscle relaxation, and glycogenolysis. In addition, an increasing number of applications in dermatology have been described, most prominently, the use as a first-line treatment for infantile hemangiomas. We here show that propranolol enhances IL-8-induced neutrophil chemotaxis and reduces the release of ROS after immune complex stimulation. To obtain further molecular insights into the modulatory effects of propranolol in activated neutrophils, we performed RNA sequencing of immune complex-stimulated neutrophils in the absence and presence of the drug. We identified the transcriptomic signature of propranolol and demonstrated an ADR2-independent immunomodulatory effect. To determine if the anti-inflammatory transcriptomic signature of propranolol also translates into clinical effects, we next evaluated the impact of propranolol in a prototypical neutrophil-dependent skin disease, specifically, antibody transfer-induced epidermolysis bullosa acquisita in mice. To validate the identified propranolol gene signature obtained in human neutrophils, we analyzed a selection of genes by RT-PCR in mouse epidermolysis bullosa acquisita skin and confirmed TNF, among others, to be differentially regulated by propranolol treatment. Our data clearly indicate that, based on its molecular impact on immune complex-activated neutrophils, propranolol is a potential treatment option for neutrophil-mediated inflammatory skin diseases.

Role of β2 Integrins in Neutrophils and Sepsis

Sepsis remains medically challenging, with high morbidity and mortality. A novel intervention is urgently needed in the absence of specific, targeted therapy. Neutrophils act as double-edged swords in sepsis; they can help to eradicate microbes, but they also contribute to tissue injury. β2 integrins are critical adhesion molecules that regulate a number of neutrophil functions. β2 integrins consist of four members, namely, αLβ2, αMβ2, αXβ2, and αDβ2. Here, we review the role of each β2 integrin in neutrophils and sepsis and consider future direction for therapeutic intervention.

Inhibitory Activity of Boesenbergia rotunda (L.) Mansf. Rhizome towards the Expression of Akt and NF-KappaB p65 in Acetic Acid-Induced Wistar Rats

Materials and Methods

Forty-eight male Wistar rats were divided into anti-inflammatory mechanism study (n = 18) and acute toxicity study (n = 30). The anti-inflammatory mechanism study employed six groups (n = 3), e.g., the normal control, negative control, positive control (quercetin 20 mg/kg BW), and three doses of BREE (250 mg/kg BW; 500 mg/kg BW; 1000 mg/kg BW). All groups (except the normal control) were inflammatory-induced i.p. using 0.1 mL of 1% of acetic acid. The expression of Akt and NF-kappaB p65 in the stomach and intestine of the rats was examined using Western blot analysis. The acute toxicity study (21 days) was conducted by following the Regulation of Indonesia National Agency of Drug and Food Control No. 7/2014 about In Vivo Nonclinical Toxicity Study using 5 doses of BREE (250 mg/kg BW; 500 mg/kg BW; 1000 mg/kg BW; 2000 mg/kg BW; 4000 mg/kg BW).

Results

BREE reduces the infiltration of inflammatory cells in both the stomach and the intestine of acetic acid-induced rats. BREE also alters the expression of Akt and NF-kappaB p65 in the rat's stomach and intestine (p=0.005). The acute toxicity study reveals no lethal effects and behavioral signs of toxicity at all tested doses, which indicates that the LD₅₀ is greater than 4000 mg/kg BW.

Conclusion

Taken together, BREE could inhibit the expression of Akt and NF-kappaB p65 in the stomach and intestine of acetic acid-induced Wistar rats. This plant could be further explored for its potential as plant-based antistomach ulceration.

Myeloid Cell-Derived Arginase in Cancer Immune Response

Amino acid metabolism is a critical regulator of the immune response, and its modulating becomes a promising approach in various forms of immunotherapy. Insufficient concentrations of essential amino acids restrict T-cells activation and proliferation. However, only arginases, that degrade L-arginine, as well as enzymes that hydrolyze L-tryptophan are substantially increased in cancer. Two arginase isoforms, ARG1 and ARG2, have been found to be present in tumors and their increased activity usually correlates with more advanced disease and worse clinical prognosis. Nearly all types of myeloid cells were reported to produce arginases and the increased numbers of various populations of myeloid-derived suppressor cells and macrophages correlate with inferior clinical outcomes of cancer patients. Here, we describe the role of arginases produced by myeloid cells in regulating various populations of immune cells, discuss molecular mechanisms of immunoregulatory processes involving L-arginine metabolism and outline therapeutic approaches to mitigate the negative effects of arginases on antitumor immune response. Development of potent arginase inhibitors, with improved pharmacokinetic properties, may lead to the elaboration of novel therapeutic strategies based on targeting immunoregulatory pathways controlled by L-arginine degradation.

Improved mouse models and advanced genetic and genomic technologies for the study of neutrophils

Mice have been excellent surrogates for studying neutrophil biology and, furthermore, murine models of human disease have provided fundamental insights into the roles of human neutrophils in innate immunity. The emergence of novel humanized mice and high-diversity mouse populations offers the research community innovative and powerful platforms for better understanding, respectively, the mechanisms by which human neutrophils drive pathogenicity, and how genetic differences underpin the variation in neutrophil biology observed among humans. Here, we review key examples of these new resources. Additionally, we provide an overview of advanced genetic engineering tools available to further improve such murine model systems, of sophisticated neutrophil-profiling technologies, and of multifunctional nanoparticle (NP)-based neutrophil-targeting strategies.

Extracellular traps (ETosis) can be activated through NADPH-dependent and -independent mechanisms in bivalve mollusks

In mammals, NETosis is a process in which the activation of neutrophils induces the release of chromatin. This DNA prevents the spread of infection by trapping, neutralizing and killing microorganisms during their interaction with antimicrobial proteins. The release of NETs is usually triggered by stimuli that promote reactive oxygen species production. Although this release of extracellular traps (ETs) has been described in some groups of invertebrates, there is a lack of basic information about them in these animals. In the present study, we describe a robust and reproducible model for the induction, analysis and quantification of ETs production using hemocytes from the bivalve Mytilus galloprovincialis. We analyzed the structure of ETs and the involvement of the ROS in the activation of this process. It was demonstrated that the formation of ETs in hemocytes can be triggered through NOX-dependent and NOX-independent pathways, depending on the stimuli used.

Transport and programmed release of nanoscale cargo from cells by using NETosis

Cells can take up nanoscale materials, which has important implications for understanding cellular functions, biocompatibility as well as biomedical applications. Controlled uptake, transport and triggered release of nanoscale cargo is one of the great challenges in biomedical applications of nanomaterials. Here, we study how human immune cells (neutrophilic granulocytes, neutrophils) take up nanomaterials and program them to release this cargo after a certain time period. For this purpose, we let neutrophils phagocytose DNA-functionalized single-walled carbon nanotubes (SWCNTs) in vitro that fluoresce in the near infrared (980 nm) and serve as sensors for small molecules. Cells still migrate, follow chemical gradients and respond to inflammatory signals after uptake of the cargo. To program release, we make use of neutrophil extracellular trap formation (NETosis), a novel cell death mechanism that leads to chromatin swelling, subsequent rupture of the cellular membrane and release of the cell's whole content. By using the process of NETosis, we can program the time point of cargo release via the initial concentration of stimuli such as phorbol 12-myristate-13-acetate (PMA) or lipopolysaccharide (LPS). At intermediate stimulation, cells continue to migrate, follow gradients and surface cues for around 30 minutes and up to several hundred micrometers until they stop and release the SWCNTs. The transported and released SWCNT sensors are still functional as shown by subsequent detection of the neurotransmitter dopamine and reactive oxygen species (H2O2). In summary, we hijack a biological process (NETosis) and demonstrate how neutrophils transport and release functional nanomaterials.

Distinct Features of Human Myeloid Cell Cytokine Response Profiles Identify Neutrophil Activation by Cytokines as a Prognostic Feature during Tuberculosis and Cancer

Myeloid cells are a vital component of innate immunity and comprise monocytes, macrophages, dendritic cells, and granulocytes. How myeloid cell lineage affects activation states in response to cytokines remains poorly understood. The cytokine environment and cellular infiltrate during an inflammatory response may contain prognostic features that predict disease outcome. In this study, we analyzed the transcriptional responses of human monocytes, macrophages, dendritic cells, and neutrophils in response to stimulation by IFN-γ, IFN-β, IFN-λ, IL-4, IL-13, and IL-10 cytokines to better understand the heterogeneity of activation states in inflammatory conditions. This generated a myeloid cell-cytokine-specific response matrix that can infer representation of myeloid cells and the cytokine environment they encounter during infection, in tumors and in whole blood. Neutrophils were highly responsive to type 1 and type 2 cytokine stimulation but did not respond to IL-10. We identified transcripts specific to IFN-β stimulation, whereas other IFN signature genes were upregulated by both IFN-γ and IFN-β. When we used our matrix to deconvolute blood profiles from tuberculosis patients, the IFN-β-specific neutrophil signature was reduced in tuberculosis patients with active disease, whereas the shared response to IFN-γ and IFN-β in neutrophils was increased. When applied to glioma patients, transcripts of neutrophils exposed to IL-4/IL-13 and monocyte responses to IFN-γ or IFN-β emerged as opposing predictors of patient survival. Hence, by dissecting how different myeloid cells respond to cytokine activation, we can delineate biological roles for myeloid cells in different cytokine environments during disease processes, especially during infection and tumor progression.

Autophagy Driven Extracellular Vesicles in the Leukaemic Microenvironment

The leukaemias are a heterogeneous group of blood cancers, which together, caused 310,000 deaths in 2016. Despite significant research into their biology and therapeutics, leukaemia is predicted to account for an increased 470,000 deaths in 2040. Many subtypes remain without targeted therapy, and therefore the mainstay of treatment remains generic cytotoxic drugs with bone marrow transplant the sole definitive option. In this review, we will focus on cellular mechanisms which have the potential for therapeutic exploitation to specifically target and treat this devastating disease. We will bring together the disciplines of autophagy and extracellular vesicles, exploring how the dysregulation of these mechanisms can lead to changes in the leukaemic microenvironment and the subsequent propagation of disease. The dual effect of these mechanisms in the disease microenvironment is not limited to leukaemia; therefore, we briefly explore their role in autoimmunity, inflammation and degenerative disease.

An Attempt to Polarize Human Neutrophils Toward N1 and N2 Phenotypes in vitro

Neutrophils act as the first line of defense against invading pathogens. Although traditionally considered in context of their antimicrobial effector functions, the importance of tumor-associated neutrophils (TANs) in the development of cancer has become increasingly clear during the last decade. With regard to their high plasticity, neutrophils were shown to acquire an anti-tumorigenic N1 or a pro-tumorigenic N2 phenotype. Despite the urgent need to get a comprehensive understanding of the interaction of TANs with their tumor microenvironment, most studies still rely on murine tumor models. Here we present for the first time a polarization attempt to generate N1 and N2 neutrophils from primary human neutrophils in vitro. Our results underscore that N1-polarized neutrophils have a pro-inflammatory phenotype characterized among others by a higher level of intercellular adhesion molecule (ICAM)-1 and high secretion of interferon (IFN)γ-induced protein 10 (IP-10)/C-X-C motif chemokine 10 (CXCL10) and tumor necrosis factor (TNF). Further, we demonstrate that neutrophils incubated under a tumor-mimicking in vitro environment show a high cell surface expression of C-X-C motif chemokine receptor 2 (CXCR2) and secrete high levels of interleukin (IL)-8. These findings suggest that it is feasible to polarize blood-derived primary human neutrophils toward N1- and N2-like phenotypes in vitro. Further, we hypothesized that the presence of anti-inflammatory neutrophil phenotype is not a phenomenon limited to cancer but also occurs when neutrophils are infected with intracellular pathogens. Indeed, our findings indicate that N2-polarized neutrophils exert a markedly decreased capacity to kill the protozoan parasite Leishmania donovani and therefore permit parasite persistence.

Preoperative leukocytosis is associated with increased tumor-infiltrating neutrophil extracellular traps and worse outcomes in esophageal cancer

Background

We evaluated the correlation between preoperative white blood cell (WBC) count and the prognosis in esophageal cancer (EC) patients who underwent esophagectomy, and explored the potential link between preoperative WBC count and tumor-infiltrating neutrophil extracellular traps (NETs) in EC.

Methods

From January 2013 to December 2017, 3,096 patients at Fudan University Shanghai Cancer Center (FUSCC) undergoing esophagectomy for EC were enrolled in this retrospective cohort. The prognostic value of preoperative WBC count together with tumor-infiltrating NETs was investigated.

Results

Leukocytosis (≥10,000/µL) was significantly associated with decreased overall survival (OS) and disease-free survival (DFS) (P<0.05). Further, moderate leukocytosis (≥7,000/µL) were also identified as an independent prognostic factor for survival. Additionally, moderate leukocytosis was correlated with male sex (P=0.006), advanced T stage (P<0.001), TNM stage (P<0.001) and ineffective postoperative chemotherapy (P<0.001), and moderate leukocytosis even predicted increased relapse postoperatively (P<0.001). Importantly, patients with moderate leukocytosis had a significantly higher level of intra-tumoral NETs infiltration (P<0.001), and the higher level of NETs infiltration were associated with worse OS and DFS (P<0.001).

Conclusions

Our data indicated that preoperative moderate leukocytosis is associated with increased tumor-infiltrating NETs and is an independent prognostic factor for survival in EC after surgery.

Neuro-Immune Circuits Regulate Immune Responses in Tissues and Organ Homeostasis

The dense innervation of the gastro-intestinal tract with neuronal networks, which are in close proximity to immune cells, implies a pivotal role of neurons in modulating immune functions. Neurons have the ability to directly sense danger signals, adapt immune effector functions and integrate these signals to maintain tissue integrity and host defense strategies. The expression pattern of a large set of immune cells in the intestine characterized by receptors for neurotransmitters and neuropeptides suggest a tight neuronal hierarchical control of immune functions in order to systemically control immune reactions. Compelling evidence implies that targeting neuro-immune interactions is a promising strategy to dampen immune responses in autoimmune diseases such as inflammatory bowel diseases or rheumatoid arthritis. In fact, electric stimulation of vagal fibers has been shown to be an extremely effective treatment strategy against overwhelming immune reactions, even after exhausted conventional treatment strategies. Such findings argue that the nervous system is underestimated coordinator of immune reactions and underline the importance of neuro-immune crosstalk for body homeostasis. Herein, we review neuro-immune interactions with a special focus on disease pathogenesis throughout the gastro-intestinal tract.

Physiological responses to cisplatin using a mouse hypersensitivity model

Background: The physiological mechanisms underlying the development of respiratory hypersensitivity to cisplatin (CDDP) are not well-understood. It has been suggested that these reactions are likely the result of type I hypersensitivity, but other explanations are plausible and the potential for CDDP to induce type I hypersensitivity responses has not been directly evaluated in an animal model. Objectives and Methods: To investigate CDDP hypersensitivity, mice were topically sensitized through application of CDDP before being challenged by oropharyngeal aspiration (OPA) with CDDP. Before and immediately after OPA challenge, pulmonary responses were assessed using whole body plethysmography (WBP). Results: CDDP did not induce an immediate response or alter the respiratory rate in sensitized mice. Two days later, baseline enhanced pause (Penh) values were significantly elevated (p < 0.05) in mice challenged with CDDP. When challenged with methacholine (Mch) aerosol, Penh values were significantly elevated (p < 0.05) in sensitized mice and respiratory rate was reduced (p < 0.05). Lymph node cell counts and immunoglobulin E levels also indicated successful sensitization to CDDP. Irrespective of the sensitization state of the mice, the number of neutrophils increased significantly in bronchoalveolar lavage fluid (BALF) following CDDP challenge. BALF from sensitized mice also contained 2.46 (±0.8) × 10⁴ eosinophils compared to less than 0.48 (±0.2) × 10⁴ cells in non-sensitized mice (p < 0.05). Conclusions: The results from this study indicate that dermal exposure to CDDP induces immunological changes consistent with type I hypersensitivity and that a single respiratory challenge is enough to trigger pulmonary responses in dermally sensitized mice. These data provide previously unknown insights into the mechanisms of CDDP hypersensitivity.

Murine Intraepithelial Dendritic Cells Interact With Phagocytic Cells During Aspergillus fumigatus-Induced Inflammation

People are constantly exposed to airborne fungal spores, including Aspergillus fumigatus conidia that can cause life-threatening conditions in immunocompromised patients or acute exacerbations in allergics. However, immunocompetent hosts do not exhibit mycoses or systemic inflammation, due to the sufficient but not excessive antifungal immune response that prevent fungal invasion. Intraepithelial dendritic cells (IE-DCs) of the conducting airway mucosa are located in the primary site of the inhalant pathogen entry; these cells can sense A. fumigatus conidia and maintain homeostasis. The mechanisms by which IE-DCs contribute to regulating the antifungal immune response and controlling conidia dissemination are not understood. To clarify the role of IE-DCs in the balance between pathogen sensing and immune tolerance we investigated the A. fumigatus conidia distribution in optically cleared mouse lungs and estimated the kinetics of the local phagocytic response during the course of inflammation. MHCII⁺ antigen-presenting cells, including IE-DCs, and CD11b⁺ phagocytes were identified by immunohistochemistry and three-dimensional fluorescence confocal laser-scanning microscopy of conducting airway whole-mounts. Application of A. fumigatus conidia increased the number of CD11b⁺ phagocytes in the conducting airway mucosa and induced the trafficking of these cells through the conducting airway wall to the luminal side of the epithelium. Some CD11b⁺ phagocytes internalized conidia in the conducting airway lumen. During the migration through the airway wall, CD11b⁺ phagocytes formed clusters. Permanently located in the airway wall IE-DCs contacted both single CD11b⁺ phagocytes and clusters. Based on the spatiotemporal characteristics of the interactions between IE-DCs and CD11b⁺ phagocytes, we provide a novel anatomical rationale for the contribution of IE-DCs to controlling the excessive phagocyte-mediated immune response rather than participating in pathogen uptake.

Treatment with anti-neonatal Fc receptor (FcRn) antibody ameliorates experimental epidermolysis bullosa acquisita in mice

Background and Purpose

Pemphigus and pemphigoid diseases are characterized and caused predominantly by IgG autoantibodies targeting structural proteins of the skin. Their current treatment relies on general and prolonged immunosuppression that causes severe adverse events, including death. Hence, novel safe and more effective treatments are urgently needed. Due to its' physiological functions, the neonatal Fc receptor (FcRn) has emerged as a potential therapeutic target for pemphigus and pemphigoid, primarily because IgG is protected from proteolysis after uptake into endothelial cells. Thus, blockade of FcRn would reduce circulating autoantibody concentrations. However, long‐term effects of pharmacological FcRn inhibition in therapeutic settings of autoimmune diseases are unknown.

Experimental Approach

Therapeutic effects of FcRn blockade were investigated in a murine model of the prototypical autoantibody‐mediated pemphigoid disease, epidermolysis bullosa acquisita (EBA). B6.SJL‐H2s C3c/1CyJ mice with clinically active disease were randomized to receive either an anti‐FcRn monoclonal antibody (4470) or an isotype control over 4 weeks.

Key Results

While clinical disease continued to worsen in isotype control‐treated mice, overall disease severity continuously decreased in mice injected with 4470, leading to almost complete remission in over 25% of treated mice. These clinical findings were paralleled by a reduction of autoantibody concentrations. Reduction of autoantibody concentrations, rather than modulating neutrophil activation, was responsible for the observed therapeutic effects.

Conclusion and Implications

The clinical efficacy of anti‐FcRn treatment in this prototypical autoantibody‐mediated disease encourages further development of anti‐FcRn antibodies for clinical use in pemphigoid diseases and potentially in other autoantibody mediated diseases.

The immune infiltration in clear cell Renal Cell Carcinoma and their clinical implications: A study based on TCGA and GEO databases

The tumor immune microenvironment in clear cell Renal Cell Carcinoma (ccRCC) still remains poorly understood. Previous methods to study the tumor immune microenvironment have a limitation when accounting for the functionally distinct cell types. In this study, we investigated the differently infiltrated immune cells and their clinical significance in ccRCC for the purpose of shedding some important light on the complex immune microenvironment in ccRCC. The devolution algorithm (CIBERSORT) was applied to infer the proportion of 22 immune infiltrating cells based on gene expression profiles of ccRCC bulk tissue, which were downloaded from TCGA and GEO databases. As a result, we observed considerable differences in immune cells percentage between ccRCC tumor tissue and paired normal tissue; meanwhile, we uncovered their internal correlations and associations with Fuhrman grade. Moreover, dendritic cells resting, dendritic cells activated, mast cells resting, mast cells activated and eosinophils were associated with favorable prognosis, whereas B cells memory, T cells follicular helper and T cells regulatory (Tregs) were correlated with poorer outcome.

The Role of Inflammation in the Pathogenesis of Osteoarthritis

A joint is the point of connection between two bones in our body. Inflammation of the joint leads to several diseases, including osteoarthritis, which is the concern of this review. Osteoarthritis is a common chronic debilitating joint disease mainly affecting the elderly. Several studies showed that inflammation triggered by factors like biomechanical stress is involved in the development of osteoarthritis. This stimulates the release of early-stage inflammatory cytokines like interleukin-1 beta (IL-1β), which in turn induces the activation of signaling pathways, such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositide 3-kinase/protein kinase B (PI3K/AKT), and mitogen-activated protein kinase (MAPK). These events, in turn, generate more inflammatory molecules. Subsequently, collagenase like matrix metalloproteinases-13 (MMP-13) will degrade the extracellular matrix. As a result, anatomical and physiological functions of the joint are altered. This review is aimed at summarizing the previous studies highlighting the involvement of inflammation in the pathogenesis of osteoarthritis.

Targeting the receptor for advanced glycation end products (RAGE) in type 1 diabetes

Type 1 diabetes (T1D) is one of the most common chronic diseases manifesting in early life, with the prevalence increasing worldwide at a rate of approximately 3% per annum. The prolonged hyperglycaemia characteristic of T1D upregulates the receptor for advanced glycation end products (RAGE) and accelerates the formation of RAGE ligands, including advanced glycation end products, high-mobility group protein B1, S100 calcium-binding proteins, and amyloid-beta. Interestingly, changes in the expression of RAGE and these ligands are evident in patients before the onset of T1D. RAGE signals via various proinflammatory cascades, resulting in the production of reactive oxygen species and cytokines. A large number of proinflammatory ligands that can signal via RAGE have been implicated in several chronic diseases, including T1D. Therefore, it is unsurprising that RAGE has become a potential therapeutic target for the treatment and prevention of disease. In this review, we will explore how RAGE might be targeted to prevent the development of T1D.

Genetic, epigenetic and biochemical regulation of succinate dehydrogenase function

Succinate dehydrogenase (SDH), complex II or succinate:quinone oxidoreductase (SQR) is a crucial enzyme involved in both the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS), the two primary metabolic pathways for generating ATP. Impaired function of SDH results in deleterious disorders from cancer to neurodegeneration. SDH function is tailored to meet the energy demands in different cell types. Thus, understanding how SDH function is regulated and how it operates in distinct cell types can support the development of therapeutic approaches against the diseases. In this article we discuss the molecular pathways which regulate SDH function and describe extra roles played by SDH in specific cell types.