Mechanisms of toxicity mediated by neutrophil and eosinophil granule proteins

A comprehensive assessment of smokeless tobacco (Shammah) extract: unraveling the effects on hematological parameters, antioxidant defense mechanisms, and organ health in rats

Shammah, also known as smokeless tobacco, is a form of tobacco product consumed without combustion, commonly used in various cultures, particularly in the Middle East and parts of Africa. The experiment was conducted in four groups control male and female, also treated male and female. The administration of Shammah extract induced significant hematological, biochemical, and histopathological changes in both female and male rats. Treated females showed a decrease in total leukocyte count (TLC) to 9900, while treated males increased to 14,525. Lymphocyte percentage decreased by 9.5% in females and 6.02% in males, with neutrophil counts rising by 24.6% and 20.5%, respectively. Eosinophil levels surged by 240% in females and 50.3% in males. Hemoglobin levels decreased by 12.4-13.1% in females, while males showed a non-significant increase to 15.68. Malondialdehyde (MDA) levels increased to 1.57 in females (57% increase) and 1.93 in males (70.8% increase). Antioxidant enzymes decreased, with superoxide dismutase (SOD) at 3.53 (116.2% decrease) in females and 3.90 (45.8% decrease) in males. Kidney function assessments revealed elevated urea levels of 36.35 (84.8% increase) in females and 43.17 (131.2% increase) in males, alongside creatinine levels of 1.28 (75.3% increase) in females and 1.56 (90.2% increase) in males. Histopathological examinations showed untreated livers with a typical structure, while treated livers exhibited infiltrative cell aggregations, venous congestion, hemorrhage, and edema. Treated kidneys showed severe glomerular atrophy and degeneration. Spleens from treated groups had blending of white and red pulp, while brains displayed hemorrhage and distorted neurons in males, and ghost neurons in females. Treated testes exhibited dilated blood vessels, edema, and reduced spermatogenesis, while treated ovaries showed cyst formation and vacuolar degeneration. These findings indicate significant oxidative stress and organ damage associated with Shammah extract exposure.

Extracellular Vesicles in Asthma: Intercellular Cross-Talk in TH2 Inflammation

Asthma is a complex, multifactorial inflammatory disorder of the airways, characterized by recurrent symptoms and variable airflow obstruction. So far, two main asthma endotypes have been identified, type 2 (T2)-high or T2-low, based on the underlying immunological mechanisms. Recently, extracellular vesicles (EVs), particularly exosomes, have gained increasing attention due to their pivotal role in intercellular communication and distal signaling modulation. In the context of asthma pathobiology, an increasing amount of experimental evidence suggests that EVs secreted by eosinophils, mast cells, dendritic cells, T cells, neutrophils, macrophages, and epithelial cells contribute to disease modulation. This review explores the role of EVs in profiling the molecular signatures of T2-high and T2-low asthma, offering novel perspectives on disease mechanisms and potential therapeutic targets.

Spatial adaptation of eosinophils and their emerging roles in homeostasis, infection and disease

Eosinophils are bone marrow-derived granulocytes that are traditionally associated with type 2 immune responses, such as those that occur during parasite infections and allergy. Emerging evidence demonstrates the remarkable functional plasticity of this elusive cell type and its pleiotropic functions in diverse settings. Eosinophils broadly contribute to tissue homeostasis, host defence and immune regulation, predominantly at mucosal sites. The scope of their activities primarily reflects the breadth of their portfolio of secreted mediators, which range from cytotoxic cationic proteins and reactive oxygen species to multiple cytokines, chemokines and lipid mediators. Here, we comprehensively review basic eosinophil biology that is directly related to their activities in homeostasis, protective immunity, regeneration and cancer. We examine how dysregulation of these functions contributes to the physiopathology of a broad range of inflammatory diseases. Furthermore, we discuss recent findings regarding the tissue compartmentalization and adaptation of eosinophils, shedding light on the factors that likely drive their functional diversification within tissues.

Eosinophils as modulators of host defense during parasitic, fungal, bacterial, and viral infections

Eosinophils, traditionally associated as central innate effector cells with type 2 immunity during allergic and helminth parasitic diseases, have recently been revealed to have important roles in tissue homeostasis as well as host defense in a broader variety of infectious diseases. In a dedicated session at the 2023 biennial conference of the International Eosinophil Society titled "Eosinophils in Host Defense," the multifaceted roles eosinophils play against diverse pathogens, ranging from parasites to fungi, bacteria, and viruses, were presented. In this review, the session speakers offer a comprehensive summary of recent discoveries across pathogen classes, positioning eosinophils as pivotal leukocytes in both host defense and pathology. By unraveling the intricacies of eosinophil engagement in host resistance, this exploration may provide valuable insights not only to understand specific underpinnings of eosinophil functions related to each class of pathogens but also to develop novel therapeutics effective against a broad spectrum of infectious diseases.

Evidence for a Role of the Long Non-Coding RNA ITGB2-AS1 in Eosinophil Differentiation and Functions

Eosinophils, a type of granulocyte derived from myeloid precursors in the bone marrow, are distinguished by their cytoplasmic granules. They play crucial roles in immunoregulation, tissue homeostasis, and host defense, while also contributing to the pathogenesis of various inflammatory diseases. Although long non-coding RNAs (lncRNAs) are known to be involved in eosinophilic conditions, their specific expression and functions within eosinophils have not been thoroughly investigated, largely due to the reliance on tissue homogenates. In an effort to address this gap, we analyzed publicly available high-throughput RNA sequencing data to identify lncRNAs associated with eosinophilic conditions. Among the identified lncRNAs, ITGB2 antisense RNA 1 (ITGB2-AS1) was significantly downregulated in blood eosinophils from patients with hypereosinophilia. To further explore its role in eosinophil biology, we generated a stable ITGB2-AS1 knockdown in the HL-60 cell line. Interestingly, ITGB2-AS1 deficiency led to impaired eosinophil differentiation, as evidenced by a reduction in cytoplasmic granules and decreased expression of key eosinophil granule proteins, including eosinophil peroxidase (EPX) and major basic protein-1 (MBP-1). Additionally, ITGB2-AS1-deficient cells exhibited compromised eosinophil effector functions, with reduced degranulation and impaired production of reactive oxygen species (ROS). These findings suggest that ITGB2-AS1 plays a pivotal role in eosinophil differentiation and function, positioning it as a novel regulator in eosinophil biology.

The relevance of eosinophils in chronic obstructive pulmonary disease: inflammation, microbiome, and clinical outcomes

Chronic obstructive pulmonary disease is caused by the inhalation of noxious particles such as cigarette smoke. The pathophysiological features include airway inflammation, alveolar destruction, and poorly reversible airflow obstruction. A subgroup of patients with chronic obstructive pulmonary disease has higher blood eosinophil counts, associated with an increased response to inhaled corticosteroids and increased biomarkers of pulmonary type 2 inflammation. Emerging evidence shows that patients with chronic obstructive pulmonary disease with increased pulmonary eosinophil counts have an altered airway microbiome. Higher blood eosinophil counts are also associated with increased lung function decline, implicating type 2 inflammation in progressive pathophysiology in chronic obstructive pulmonary disease. We provide a narrative review of the role of eosinophils and type 2 inflammation in the pathophysiology of chronic obstructive pulmonary disease, encompassing the lung microbiome, pharmacological targeting of type 2 pathways in chronic obstructive pulmonary disease, and the clinical use of blood eosinophil count as a chronic obstructive pulmonary disease biomarker.

Eosinophil extracellular traps in respiratory ailment: Pathogenic mechanisms and clinical translation

Background

Eosinophilic extracellular traps (EETs) are reticular complexes comprising deoxyribonucleic-Acid (DNA) fibers and granule proteins.

Aims

EETs play a crucial role in antimicrobial host responses and are pathogenic when overproduced or under degraded. EETs created by eosinophils appear to enable vital immune responses against extra-cellular pathogens, nevertheless, trap overproduction is evident in pathology.

Materials & Methods

As considerably research is performed, new data affirmed that EETs can alter the outcome of respiratory ailment.

Results

We probe into the disclosure and specificity of EETs produced in reaction to various stimuli and propose a role for those frameworks in ailment pathogenesis and the establishment of chronic, unresolved inflammation.

Discussion

Whether EETs can be used as a prospective brand-new target for the diagnosis, treatment and prognosis of respiratory ailments is a scientific theme worth studying.

Conclusion

We probe into the disclosure and specificity of EETs produced in reaction to various stimuli and propose a role for those frameworks in ailment pathogenesis and the establishment of chronic, unresolved inflammation.

Assessment of immunopathological responses of a novel non-chemical biocide in C57BL/6 for safe disinfection usage

BACKGROUND

Water electrospray technology has been developed and extensively studied for its physical properties and potential application as a non-chemical biocide against airborne pathogens. However, there are still concerns regarding the safety and potential toxicity of inhaling water electrospray (WE) particles. To address these potential hazards and offer insights into the impact of WE on humans, we analyzed the immunopathological response to WE by employing an intranasal challenge C57BL/6 mouse model. This analysis aimed to compare the effects of WE with those of sodium hypochlorite (SH), a well-known biocidal agent.

RESULTS

The study findings suggest that the WE did not trigger any pathological immune reactions in the intranasal-challenged C57BL/6 mouse model. Mice challenged with WE did not experience body weight loss, and there was no increase in inflammatory cytokine production compared to SH-treated mice. Histopathological analysis revealed that WE did not cause any damage to the lung tissue. In contrast, mice treated with SH exhibited significant lung tissue damage, characterized by the infiltration of neutrophils and eosinophils. Transcriptomic analysis of lung tissue further confirmed the absence of a pathological immune response in mice treated with WE compared to those treated with SH. Upon intranasal challenge with WE, the C57BL/6 mouse model did not show any evidence of immunopathological damage.

CONCLUSIONS

The results of this study suggest that WE is a safe technology for disinfecting airborne pathogens. It demonstrated little to no effect on immune system activation and pathological outcomes in the intranasal challenge C57BL/6 mouse model. These findings not only support the potential use of WE as an effective and safe method for air disinfection but also highlight the value of the intranasal challenge of the C57BL/6 mouse model in providing significant immunopathological insights for assessing the inhalation of novel materials for potential use.

Formyl peptide enhances cancer immunotherapy by activating antitumoral neutrophils, and T cells

Neutrophils are heterogeneous and plastic, with the ability to polarize from antitumour to protumour phenotype and modulate tumour microenvironment components. While some advances have been made, the neutrophil-targeting therapy remains underexplored. Activation of formyl peptide receptors (FPRs) by formylated peptides is needed for local control of infection through the recruitment of activated neutrophils while the potential contribution of antitumour activity remains underexplored. Here, we demonstrate that neutrophils can be harnessed to suppress tumour growth through the action of the formyl peptide (FP) on the formyl peptide receptor (FPR). Mechanistically, FP efficiently recruits neutrophils to produce reactive oxygen species production (ROS), resulting in the direct killing of tumours. Antitumour functions disappeared when neutrophils were depleted by anti-Ly6G antibodies. Interestingly, extensive T-cell activation was observed in mouse tumours treated with FP, showing the potential to alter the immune suppressed tumour microenvironment (TME) and further sensitize mice to anti-PD1 therapy. Transcriptomic and flow cytometry analyses revealed the mechanisms of FP-sensitized anti-PD1 therapy, mainly including stimulated neutrophils and an altered immune-suppressed tumour microenvironment. Collectively, these data establish FP as an effective combination partner for sensitizing anti-PD1 therapy by stimulating tumour-infiltrated neutrophils.

Exploring the role of eosinophil cationic protein (ECP) in schizophrenia: Insights and implications

Schizophrenia, a multifaceted neuropsychiatric disorder characterized by disruptions in perception, cognition, and behavior, has been associated with neuroinflammatory processes. Emerging research has increasingly recognized the potential involvement of immune-related factors in the pathogenesis of schizophrenia, prompting investigations into biomarkers associated with inflammatory cascades. Among these biomarkers, Eosinophil Cationic Protein (ECP), traditionally known for its role in eosinophil-mediated immune responses, has garnered attention for its putative association with neuroinflammation in schizophrenia. This paper critically examines the current understanding of the role of ECP in schizophrenia. ECP, a cytotoxic protein released by eosinophils, has diverse immunomodulatory effects and has been identified in altered concentrations in individuals with schizophrenia. Studies have reported elevated levels of ECP in peripheral fluids of schizophrenia patients, suggesting a possible link between ECP dysregulation and the inflammatory milieu characteristic of the disorder. Moreover, the potential implications of ECP in neuroinflammatory processes relevant to schizophrenia pathophysiology are discussed. ECP's role in modulating immune responses and its potential impact on neuronal function, synaptic plasticity, and neurotoxicity within the central nervous system (CNS) are considered, highlighting the potential contribution of ECP to the neuroinflammatory mechanisms underlying schizophrenia. In conclusion, while the precise role of ECP in schizophrenia pathogenesis warrants further elucidation, exploring its association with neuroinflammation holds promise in unraveling new biomarkers and therapeutic avenues for managing this complex psychiatric disorder.

Cardiac Mechanics and Valvular and Vascular Abnormalities in Hypereosinophilic Syndrome

Hypereosinophilic syndrome (HES) is considered to be a rare myeloproliferative disease that is characterized by persistent eosinophilia with associated multiple-organ damage. The heart is often involved in HES, representing a major cause of morbidity and mortality. HES is a heterogeneous group of disorders; the majority of the cases are idiopathic. Summarizing the findings regarding myocardial, valvular, and vascular abnormalities in a series of patients with HES, most studies found normal left ventricular (LV) volumes with reduced LV global longitudinal strain and LV apical rotation and twist in HES cases, accompanied by increased left atrial (LA) volumes and stroke volumes, reduced peak LA circumferential strain (representing systolic abnormalities), and mitral annular dilation and functional deterioration. Regarding the right heart, preserved right ventricular volumes and functional properties, increased right atrial volumes, mild RA functional abnormalities, and dilated tricuspid annular dimensions without functional impairment could be seen in these studies. Aortic and pulmonary valves showed no specific disease-related alterations. Vascular abnormalities included increased aortic stiffness without dilation of the aorta and pulmonary hypertension in some cases. These results suggest disease-specific but relatively mild myocardial, valvular, and vascular abnormalities in HES. The present review aimed to summarize the available clinical data about cardiac mechanics and valvular and vascular abnormalities in a series of patients with HES.

Syntaxin-4 and SNAP23 are involved in neutrophil degranulation, but not in the release of mitochondrial DNA during NET formation

Neutrophils are a specialized subset of white blood cells, which have the ability to store pre-formed mediators in their cytoplasmic granules. Neutrophils are well-known effector cells involved in host protection against pathogens through diverse mechanisms such as phagocytosis, degranulation, extracellular traps, and oxidative burst. In this study, we provide evidence highlighting the significance of the SNARE proteins syntaxin-4 and synaptosomal-associated protein (SNAP) 23 in the release of azurophilic granules, specific granules, and the production of reactive oxygen species in human neutrophils. In contrast, the specific blockade of either syntaxin-4 or SNAP23 did not prevent the release of mitochondrial dsDNA in the process of neutrophil extracellular trap (NET) formation. These findings imply that degranulation and the release of mitochondrial dsDNA involve at least partially distinct molecular pathways in neutrophils.

Role of Mitochondria in the Regulation of Effector Functions of Granulocytes

Granulocytes (neutrophils, eosinophils, and basophils) are the most abundant circulating cells in the innate immune system. Circulating granulocytes, primarily neutrophils, can cross the endothelial barrier and activate various effector mechanisms to combat invasive pathogens. Eosinophils and basophils also play an important role in allergic reactions and antiparasitic defense. Granulocytes also regulate the immune response, wound healing, and tissue repair by releasing of various cytokines and lipid mediators. The effector mechanisms of granulocytes include the production of reactive oxygen species (ROS), degranulation, phagocytosis, and the formation of DNA-containing extracellular traps. Although all granulocytes are primarily glycolytic and have only a small number of mitochondria, a growing body of evidence suggests that mitochondria are involved in all effector functions as well as in the production of cytokines and lipid mediators and in apoptosis. It has been shown that the production of mitochondrial ROS controls signaling pathways that mediate the activation of granulocytes by various stimuli. In this review, we will briefly discuss the data on the role of mitochondria in the regulation of effector and other functions of granulocytes.

NBEAL2 deficiency in humans leads to low CTLA-4 expression in activated conventional T cells

Loss of NBEAL2 function leads to grey platelet syndrome (GPS), a bleeding disorder characterized by macro-thrombocytopenia and α-granule-deficient platelets. A proportion of patients with GPS develop autoimmunity through an unknown mechanism, which might be related to the proteins NBEAL2 interacts with, specifically in immune cells. Here we show a comprehensive interactome of NBEAL2 in primary T cells, based on mass spectrometry identification of altogether 74 protein association partners. These include LRBA, a member of the same BEACH domain family as NBEAL2, recessive mutations of which cause autoimmunity and lymphocytic infiltration through defective CTLA-4 trafficking. Investigating the potential association between NBEAL2 and CTLA-4 signalling suggested by the mass spectrometry results, we confirm by co-immunoprecipitation that CTLA-4 and NBEAL2 interact with each other. Interestingly, NBEAL2 deficiency leads to low CTLA-4 expression in patient-derived effector T cells, while their regulatory T cells appear unaffected. Knocking-down NBEAL2 in healthy primary T cells recapitulates the low CTLA-4 expression observed in the T cells of GPS patients. Our results thus show that NBEAL2 is involved in the regulation of CTLA-4 expression in conventional T cells and provide a rationale for considering CTLA-4-immunoglobulin therapy in patients with GPS and autoimmune disease.

Functional Amyloids: Where Supramolecular Amyloid Assembly Controls Biological Activity or Generates New Functionality

Functional amyloids are a rapidly expanding class of fibrillar protein structures, with a core cross-β scaffold, where novel and advantageous biological function is generated by the assembly of the amyloid. The growing number of amyloid structures determined at high resolution reveal how this supramolecular template both accommodates a wide variety of amino acid sequences and also imposes selectivity on the assembly process. The amyloid fibril can no longer be considered a generic aggregate, even when associated with disease and loss of function. In functional amyloids the polymeric β-sheet rich structure provides multiple different examples of unique control mechanisms and structures that are finely tuned to deliver assembly or disassembly in response to physiological or environmental cues. Here we review the range of mechanisms at play in natural, functional amyloids, where tight control of amyloidogenicity is achieved by environmental triggers of conformational change, proteolytic generation of amyloidogenic fragments, or heteromeric seeding and amyloid fibril stability. In the amyloid fibril form, activity can be regulated by pH, ligand binding and higher order protofilament or fibril architectures that impact the arrangement of associated domains and amyloid stability. The growing understanding of the molecular basis for the control of structure and functionality delivered by natural amyloids in nearly all life forms should inform the development of therapies for amyloid-associated diseases and guide the design of innovative biomaterials.

The impact of soy products, isoflavones, and Lactobacillus acidophilus on iron status and morphological parameters in healthy female rats

BACKGROUND

Isoflavones and probiotics are two major factors involved in bone health. Osteoporosis and disturbances in iron (Fe) levels are common health problems in aging women. This study aimed to analyze how soybean products, daidzein, genistein, and Lactobacillus acidophilus (LA) affect Fe status and blood morphological parameters in healthy female rats.

METHODS

A total of 48 Wistar rats aged 3 months were randomly divided into six groups. The control group (K) received a standard diet (AIN 93 M). The remaining five groups received a standard diet supplemented with the following: tempeh flour (TP); soy flour (RS); daidzein and genistein (DG); Lactobacillus acidophilus DSM20079 (LA); as well as a combination of daidzein, genistein, and L. acidophilus DSM20079 (DGLA). After 8 weeks of intervention, blood samples of the rats were collected for morphological analysis, whereas tissue samples were collected and kept at -80 °C until Fe analysis. Red blood cells, hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelets (PLTs), red cell distribution width, white blood cells, neutrophils (NEUT), lymphocytes (LYM), monocytes, eosinophils (EOS), and basophils were measured for blood morphological analysis. Fe concentrations were determined using flame atomic spectrometry. For statistical analysis, an ANOVA test for significance at the 5 % level was used. The relationship between tissue Fe levels and blood morphological parameters was determined using Pearson's correlation.

RESULTS

Although no significant differences were observed in the Fe content between all diets, the TP group showed significantly higher levels of NEUT and lower levels of LYM than the control group. Compared with the DG and DGLA groups, the TP group showed a dramatically higher PLT level. In addition, the RS group showed significantly higher Fe concentrations in the spleen compared with the standard diet. Compared with the DG, LA, and DGLA groups, the RS group also showed significantly higher Fe concentrations in the liver. Compared with the TP, DG, LA, and DGLA groups, the RS group showed dramatically higher Fe concentrations in the femur. Pearson's correlations between blood morphological parameters and Fe levels in tissues were observed, especially a negative correlation between the Fe level in the femur and the NEUT concentration (-0.465) and a strong positive correlation between the Fe level in the femur and the LYM concentration (0.533).

CONCLUSION

Soybean flour was found to increase Fe levels in rats, whereas tempeh may alter anti-inflammatory blood parameters. Isoflavones and probiotics did not affect Fe status in healthy female rats.

Evaluation of physicochemical parameters, acute and subchronic toxicities, and anti-diabetic activity of Spondias venulosa (Engl.) Mart. ex Engl. leaf extract on alloxan-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Spondias venulosa is a medicinal plant whose leaves are popularly used for decades in Northeast Nigeria as a first-choice medicinal plants for the treatment of diabetes. This claim has not been proven scientifically.

AIM OF THE STUDY

The present study was carried out to determine the physicochemical profiles, acute, sub-chronic toxicities, and antidiabetic activity the leaf extract in alloxan-induced diabetic rats.

MATERIALS AND METHODS

The physicochemical parameters of S. venulosa leaves, acute, subchronic toxicities, and antidiabetic activity in alloxan-induced diabetic rats were determined using standard procedures. All physicochemical parameters were carried out triplicate. Acute and subchronic toxicity studies were carried out following OECD guidelines by administering maximum extract dose of 2000 mg/kg orally to Wistar rats. Subchronic toxicity and antidiabetic studies were carried out in rats of opposite sexes at doses 300, 600, and 1200 mg/kg (orally).

RESULTS

Results obtained showed that the moisture content, water soluble extractive, and organic matter had values of 4.98 ± 1.01, 12.04 ± 1.24 and 1.01 ± 0.01% w/w respectively. The metallic contents of the methanol leaf extract revealed the presence of zinc with value of 12.01 ± 1.01 ppm (normal range:< 100 mg/kg DM) and copper with value of 6.24 ± 2.14 ppm (normal range:< 30 mg/kg DM). Oral median lethal dose (LD50) was estimated to be greater than 2000 mg/kg since the extract did not produce any sign of toxicity or death in short term while, subchronic toxicity study showed that there was no significant weight loss in the rats after 28 days of extract administration. All hematology and biochemical parameters showed no elevated values when compared to the control group (p < 0.05). Histopathological examinations of major organs do not show signs of organ damages which indicate that the extract was safe at the doses administered. Oral administration of extract doses for 30 days reduced blood glucose levels in alloxan-induced diabetic rats in dose-dependent manner compared (p < 0.05) to standard drug (Glibenclamide).

CONCLUSIONS

Our study showed some physicochemical parameters of S. venulosa leaf which are essential for its identification from closely related species in traditional medicine. The study further showed that S. venulosa methanol leaf extract possessed antidiabetic activity, thus, justifying its use for the treatment of diabetes in Nigeria. However, there is need to identify and investigate the bioactive compound(s) responsible for the activity towards drug discovery.

Advances in antibody-based therapy in oncology

Monoclonal antibodies are a growing class of targeted cancer therapeutics, characterized by exquisite specificity, long serum half-life, high affinity and immune effector functions. In this review, we outline key advances in the field with a particular focus on recent and emerging classes of engineered antibody therapeutic candidates, discuss molecular structure and mechanisms of action and provide updates on clinical development and practice.

Think Beyond Particle Cytotoxicity: When Self-Cellular Components Released After Immunogenic Cell Death Explain Chronic Disease Development

The prolonged perturbation of the immune system following the release of a plethora of self-molecules (known as damage-associated molecular patterns, DAMPs) by stressed or dying cells triggers acute and chronic pathological responses. DAMPs are commonly released after plasma membrane damage or complete rupture due to immunogenic cell death (ICD), upon numerous stressors including infectious and toxic agents. The set of DAMPs released after ICD include mature proinflammatory cytokines and alarmins, but also polymeric macromolecules. These self-intracellular components are recognized by injured and healthy surrounding cells via innate receptors, and induce upregulation of stress-response mechanisms, including inflammation. In this review, by overstepping the simple toxicological evaluation, we apply ICD and DAMP concepts to silica cytotoxicity, providing new insights on the mechanisms driving the progress and/or the exacerbation of certain SiO2–related pathologies. Finally, by proposing self-DNA as new crucial DAMP, we aim to pave the way for the development of innovative and easy-to-perform predictive tests to better identify the hazard of fine and ultrafine silica particles. Importantly, such mechanisms could be extended to nano/micro plastics and diesel particles, providing strategic advice and reports on their health issues.

Neutrophils and polymorphonuclear myeloid-derived suppressor cells: an emerging battleground in cancer therapy

Neutrophils are central mediators of innate and adaptive immunity and first responders to tissue damage. Although vital to our health, their activation, function, and resolution are critical to preventing chronic inflammation that may contribute to carcinogenesis. Cancers are associated with the expansion of the neutrophil compartment with an escalation in the number of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) in the peripheral circulation and tumor microenvironment. Although phenotypically similar to classically activated neutrophils, PMN-MDSC is pathologically activated and immunosuppressive in nature. They dynamically interact with other cell populations and tissue components and convey resistance to anticancer therapies while accelerating disease progression and metastatic spread. Cancer-associated neutrophilia and tumor infiltration of neutrophils are significant markers of poor outcomes in many cancers. Recently, there has been significant progress in the identification of molecular markers of PMN-MDSC providing insights into the central role of PMN-MDSC in the local tumor microenvironment as well as the systemic immune response in cancer. Further advances in sequencing and proteomics techniques will improve our understanding of their diverse functionalities and the complex molecular mechanisms at play. Targeting PMN-MDSC is currently one of the major focus areas in cancer research and several signaling pathways representing possible treatment targets have been identified. Positive results from preclinical studies clearly justify the current investigation in drug development and thus novel therapeutic strategies are being evaluated in clinical trials. In this review, we discuss the involvement of PMN-MDSC in cancer initiation and progression and their potential as therapeutic targets and clinical biomarkers in different cancers.

Assessing the health hazard originated via pesticide chemicals in human through rabbit model in agricultural production system in Bangladesh

BACKGROUND

The use of chemical pesticides in developing countries like Bangladesh and their impacts on human health and food security is a global concern. Bangladesh is an agricultural dependent country for the growing population demand for food security and food safety. We conduct this study to assess public health threats of commonly utilised pesticides including malathion and nitrobenzene in female rabbit model.

METHODS

Thirty New Zealand White healthy rabbit was divided randomly into three groups; and subjected to distilled water as control, malathion@ 5 mg/kg body weight and nitrobenzene@ 5 mg/kg body i.p daily for the next 15 days. Hematology, serum biochemistry and hormonal assay were performed.

RESULTS

Red blood cell (RBC) concentrations (TEC, Hb, PCV%) were reduced in rabbits exposed to malathion and nitrobenzene. The neutrophil and eosinophil percentage were increased in the malathion and nitrobenzene exposed juvenile rabbit group. We found that serum aspartate aminotransferase (AST) and creatinine were increased in the nitrobenzene exposed group in infants, whereas malathion exposure increased serum alanine aminotransferase (ALT). In contrast, the juvenile group exposed to malathion increased the ALT level. There was no change in AST or creatinine levels in juvenile rabbits exposed to malathion or nitrobenzene. Serum estradiol levels were significantly lower in rabbits exposed to malathion and nitrobenzene. Serum testosterone concentration was increased in juvenile rabbits exposed to malathion and nitrobenzene, but progesterone was decreased in malathion exposed juvenile rabbits.

CONCLUSION

However, this study highlights the importance of rigorous monitoring and testing of agricultural products. In addition, strengthen research and extension in the fields of agro economy, organic farming, local universities and farmer associations.

Molecular Basis for Paradoxical Activities of Polymorphonuclear Neutrophils in Inflammation/Anti-Inflammation, Bactericide/Autoimmunity, Pro-Cancer/Anticancer, and Antiviral Infection/SARS-CoV-II-Induced Immunothrombotic Dysregulation

Polymorphonuclear neutrophils (PMNs) are the most abundant white blood cells in the circulation. These cells act as the fast and powerful defenders against environmental pathogenic microbes to protect the body. In addition, these innate inflammatory cells can produce a number of cytokines/chemokines/growth factors for actively participating in the immune network and immune homeostasis. Many novel biological functions including mitogen-induced cell-mediated cytotoxicity (MICC) and antibody-dependent cell-mediated cytotoxicity (ADCC), exocytosis of microvesicles (ectosomes and exosomes), trogocytosis (plasma membrane exchange) and release of neutrophil extracellular traps (NETs) have been successively discovered. Furthermore, recent investigations unveiled that PMNs act as a double-edged sword to exhibit paradoxical activities on pro-inflammation/anti-inflammation, antibacteria/autoimmunity, pro-cancer/anticancer, antiviral infection/COVID-19-induced immunothrombotic dysregulation. The NETs released from PMNs are believed to play a pivotal role in these paradoxical activities, especially in the cytokine storm and immunothrombotic dysregulation in the recent SARS-CoV-2 pandemic. In this review, we would like to discuss in detail the molecular basis for these strange activities of PMNs.

Neutrophils and schistosomiasis: a missing piece in pathology

Schistosomiasis is a chronic human parasitic disease that causes serious health problems worldwide. The disease-associated liver pathology is one of the hallmarks of infections by S. mansoni and S. japonicum, and is accountable for the debilitating condition found in infected patients. In the past few years, investigative studies have highlighted the key role played by neutrophils and the influence of inflammasome signaling pathway in different pathological conditions. However, it is noteworthy that the study of inflammasome activation in neutrophils has been overlooked by reports concerning macrophages and monocytes. This interplay between neutrophils and inflammasomes is much more poorly investigated during schistosomiasis. Herein we reviewed the role of neutrophils during schistosomiasis and addressed the potential connection between these cells and inflammasome activation in this context.

Evaluation of Immune Response and Haematological Parameters in Infected Male Albino Rats by Giardiasis

The present work aimed to study the effects of G. lamblia infection on immunological, haematological studies and to evaluate immunoglobulins and some cytokines. Fifty male albino rats were divided into six groups. The control group including 20 rats and the infected group includes 30 rats. All the estimations were checked all over five checkpoints (CP) (7, 14, 21, 28, and 35 days post-infection). Serum levels of IgA, IgG, IgM and IgE. Cytokines INF-γ, TNF-alpha, IL-4, IL-10, and haematological parameters were determined. Cyst and trophozoite were counted. A considerable increase in the level of immunoglobulins and cytokines in all infected groups compared to the control group was documented. Furthermore, a significant decrease in red blood corpuscles, haemoglobin, and mean corpuscular haemoglobin concentration levels, whereas substantial increases in mean corpuscular volume, mean corpuscular haemoglobin and platelets were observed. Moreover, infected rats had a substantial rise in WBCs, lymphocytes, and eosinophil counts compared to the control group, whereas neutrophils and monocytes had a significant decrease. Number of trophozoites and cysts were significantly increased in infected groups before diminishing after day 28. The current results showed that Th1 and Th2 immune responses, which are characterized by the production of TNF-α, IFN-γ, IL-4 and IL-10, are important for protection against Giardia infections and also verified the balance between these cytokines and the timing of their production was crucial in G. lamblia immune response. Giardia lamblia, Immunity, Antibodies, cytokines, eosinophil.

Neutrophil Death in Myeloproliferative Neoplasms: Shedding More Light on Neutrophils as a Pathogenic Link to Chronic Inflammation

Neutrophils are an essential component of the innate immune response, but their prolonged activation can lead to chronic inflammation. Consequently, neutrophil homeostasis is tightly regulated through balance between granulopoiesis and clearance of dying cells. The bone marrow is both a site of neutrophil production and the place they return to and die. Myeloproliferative neoplasms (MPN) are clonal hematopoietic disorders characterized by the mutations in three types of molecular markers, with emphasis on Janus kinase 2 gene mutation (JAK2V617F). The MPN bone marrow stem cell niche is a site of chronic inflammation, with commonly increased cells of myeloid lineage, including neutrophils. The MPN neutrophils are characterized by the upregulation of JAK target genes. Additionally, MPN neutrophils display malignant nature, they are in a state of activation, and with deregulated apoptotic machinery. In other words, neutrophils deserve to be placed in the midst of major events in MPN. Our crucial interest in this review is better understanding of how neutrophils die in MPN mirrored by defects in apoptosis and to what possible extent they can contribute to MPN pathophysiology. We tend to expect that reduced neutrophil apoptosis will establish a pathogenic link to chronic inflammation in MPN.

Assessment of the acute and sub-acute toxicity of the ethanolic extract of the aerial parts of Crassocephalum rabens (Asteraceae) in rats

This pioneering study was to assess the acute and sub-acute toxicity of the ethanolic extract of the aerial parts of Crassocephalum rabens (Asteraceae) in rats. C. rabens is a common vegetable and herb for treating inflammation-related syndromes in Taiwan. Pharmacological studies have unveiled that the extracts of C. rabens have potential to become hepatoprotective, anti-inflammatory, or anti-cancer agents. The toxicological effects of the aerial parts of C. rabens in rodents are still elusive. For the acute toxicity study, rats were administrated with a single dose of 5,000 mg/kg body weight (BW) and observed for 14 days in accordance with the Organization for Economic Cooperation and Development (OECD) guideline No. 420. For the sub-acute toxicity study, animals were orally treated with daily doses of 0, 416.7, 833.3, and 1,666.7 mg/kg BW for 28 days based on the OECD guideline No. 407. The toxicity of the repeated dose was observed with anthropometric, hematological, and biochemical parameters as well as histology. The mortality and critical pathological and biochemical abnormalities were not observed in the acute and/or sub-acute toxicity studies. The oral median lethal dose (LD₅₀) of the extract was greater than 5000 mg/kg BW. The no-observed-adverse-effect-level (NOAEL) in male and female rats was greater than 1,666.7 mg/kg BW. As such, the extract of the aerial parts of C. rabens is considered a non-toxic substance.

The Immune System Throws Its Traps: Cells and Their Extracellular Traps in Disease and Protection

The first formal description of the microbicidal activity of extracellular traps (ETs) containing DNA occurred in neutrophils in 2004. Since then, ETs have been identified in different populations of cells involved in both innate and adaptive immune responses. Much of the knowledge has been obtained from in vitro or ex vivo studies; however, in vivo evaluations in experimental models and human biological materials have corroborated some of the results obtained. Two types of ETs have been described—suicidal and vital ETs, with or without the death of the producer cell. The studies showed that the same cell type may have more than one ETs formation mechanism and that different cells may have similar ETs formation mechanisms. ETs can act by controlling or promoting the mechanisms involved in the development and evolution of various infectious and non-infectious diseases, such as autoimmune, cardiovascular, thrombotic, and neoplastic diseases, among others. This review discusses the presence of ETs in neutrophils, macrophages, mast cells, eosinophils, basophils, plasmacytoid dendritic cells, and recent evidence of the presence of ETs in B lymphocytes, CD4+ T lymphocytes, and CD8+ T lymphocytes. Moreover, due to recently collected information, the effect of ETs on COVID-19 is also discussed.

The Enigma of Eosinophil Degranulation

Eosinophils are specialized white blood cells, which are involved in the pathology of diverse allergic and nonallergic inflammatory diseases. Eosinophils are traditionally known as cytotoxic effector cells but have been suggested to additionally play a role in immunomodulation and maintenance of homeostasis. The exact role of these granule-containing leukocytes in health and diseases is still a matter of debate. Degranulation is one of the key effector functions of eosinophils in response to diverse stimuli. The different degranulation patterns occurring in eosinophils (piecemeal degranulation, exocytosis and cytolysis) have been extensively studied in the last few years. However, the exact mechanism of the diverse degranulation types remains unknown and is still under investigation. In this review, we focus on recent findings and highlight the diversity of stimulation and methods used to evaluate eosinophil degranulation.

Eosinophils in skin diseases

Eosinophil infiltration is a common finding in a broad spectrum of skin diseases, despite the fact that the skin is devoid of eosinophils under physiologic conditions. Although cutaneous eosinophilia is reactive, cytokine-mediated in most cases, diseases with an intrinsic mutation-mediated clonal expansion of eosinophils can also manifest on the skin. As eosinophils are involved in host defense, regulate immune responses, generate pruritus, induce remodeling and fibrosis, and can cause tissue damage, they have the capacity to actively contribute to the pathogenesis of diseases. Recent research provided deeper insights in the mechanisms, e.g., bacterial and viral clearance, blister formation, recruitment of cytotoxic T cells, and generation of pruritus, by which eosinophils might come into action. This review aims at providing an overview on the clinical presentations of eosinophil-associated dermatoses and the current understanding of their pathogenic role in these diseases. Further, we discuss the effects of therapies targeting eosinophils.

Regulation of eosinophil functions by autophagy

Eosinophils are granule-containing leukocytes which develop in the bone marrow. For many years, eosinophils have been recognized as cytotoxic effector cells, but recent studies suggest that they perform additional immunomodulatory and homeostatic functions. Autophagy is a conserved intracellular process which preserves cellular homeostasis. Autophagy defects have been linked to the pathogenesis of many human disorders. Evidence for abnormal regulation of autophagy, including decreased or increased expression of autophagy-related (ATG) proteins, has been reported in several eosinophilic inflammatory disorders, such as Crohn's disease, bronchial asthma, eosinophilic esophagitis, and chronic rhinosinusitis. Despite the increasing extent of research using preclinical models of immune cell-specific autophagy deficiency, the physiological relevance of autophagic pathway in eosinophils has remained unknown until recently. Owing to the increasing evidence that eosinophils play a role in keeping organismal homeostasis, the regulation of eosinophil functions is of considerable interest. Here, we discuss the most recent advances on the role of autophagy in eosinophils, placing particular emphasis on insights obtained in mouse models of infections and malignant diseases in which autophagy has genetically dismantled in the eosinophil lineage. These studies pointed to the possibility that autophagy-deficient eosinophils exaggerate inflammation. Therefore, the pharmacological modulation of the autophagic pathway in these cells could be used for therapeutic interventions.

The twilight zone: plasticity and mixed ontogeny of neutrophil and eosinophil granulocyte subsets

It is now becoming clear that neutrophils and eosinophils are heterogeneous cells with potentially multiple subsets in health and disease. With greater marker coverage by multi-color flow cytometry and single-cell level sequencing of granulocyte populations, novel phenotypes of these cells began to emerge. Intriguingly, many newly described subsets blend distinctions between classical myeloid lineage phenotypes, which are especially true for tissue resident or recruited cells in contexts of inflammation and disease. This includes reports of neutrophils with features of eosinophils, monocytes and dendritic cells, and eosinophil subsets expressing neutrophil markers. Moreover, novel studies show the ability of immature neutrophils to transdifferentiate into mature cells belonging to other myeloid lineages (eosinophils, monocytes/macrophages). In this review, we summarize novel findings in this exciting research frontier and shed light on potential processes driving the plasticity and heterogeneity of granulocyte subsets. Specifically, we discuss the hematopoietic flexibility of granulocyte precursors in bone marrow and the adaptation of myeloid cells to local tissue microenvironments. The understanding of such intermediate and developmental phenotypes is very important, as it can teach us about origins of functionally distinct myeloid cells during inflammation, and explain reasons for successes and failures of biologics targeting terminally differentiated granulocytes.

Intestinal eosinophils, homeostasis and response to bacterial intrusion

Eosinophils are traditionally considered as end-stage effector cells involved in the pathogenesis of Th2 immune-mediated disorders as well as in the protection against parasite infection. However, this restricted view has recently been challenged by a series of studies revealing the highly plastic nature of these cells and implication in various homeostatic processes. Large numbers of eosinophils reside in the lamina propria of the gastrointestinal tract, at the front line of host defence, where they contribute to maintain the intestinal epithelial barrier function in the face of inflammation-associated epithelial cell damage. Eosinophils confer active protection against bacterial pathogens capable of penetrating the mucosal barrier through the release of cytotoxic compounds and the generation of extracellular DNA traps. Eosinophils also integrate tissue-specific cytokine signals such as IFN-γ, which synergise with bacterial recognition pathways to enforce different context-dependent functional responses, thereby ensuring a rapid adaptation to the ever-changing intestinal environment. The ability of eosinophils to regulate local immune responses and respond to microbial stimuli further supports the pivotal role of these cells in the maintenance of tissue homeostasis at the intestinal interface.

The Release Kinetics of Eosinophil Peroxidase and Mitochondrial DNA Is Different in Association with Eosinophil Extracellular Trap Formation

Eosinophils are a subset of granulocytes characterized by a high abundance of specific granules in their cytoplasm. To act as effector cells, eosinophils degranulate and form eosinophil extracellular traps (EETs), which contain double-stranded DNA (dsDNA) co-localized with granule proteins. The exact molecular mechanism of EET formation remains unknown. Although the term “EET release” has been used in scientific reports, it is unclear whether EETs are pre-formed in eosinophils and subsequently released. Moreover, although eosinophil degranulation has been extensively studied, a precise time-course of granule protein release has not been reported until now. In this study, we investigated the time-dependent release of eosinophil peroxidase (EPX) and mitochondrial DNA (mtDNA) following activation of both human and mouse eosinophils. Unexpectedly, maximal degranulation was already observed within 1 min with no further change upon complement factor 5 (C5a) stimulation of interleukin-5 (IL-5) or granulocyte/macrophage colony-stimulating factor (GM-CSF)-primed eosinophils. In contrast, bulk mtDNA release in the same eosinophil populations occurred much slower and reached maximal levels between 30 and 60 min. Although no single-cell analyses have been performed, these data suggest that the molecular pathways leading to degranulation and mtDNA release are at least partially different. Moreover, based on these data, it is likely that the association between the mtDNA scaffold and granule proteins in the process of EET formation occurs in the extracellular space.