Understanding the Multifaceted Role of Neutrophils in Cancer and Autoimmune Diseases

Mechanism of inflammatory response and therapeutic effects of stem cells in ischemic stroke: current evidence and future perspectives

Ischemic stroke is a leading cause of death and disability worldwide, with an increasing trend and tendency for onset at a younger age. China, in particular, bears a high burden of stroke cases. In recent years, the inflammatory response after stroke has become a research hotspot: understanding the role of inflammatory response in tissue damage and repair following ischemic stroke is an important direction for its treatment. This review summarizes several major cells involved in the inflammatory response following ischemic stroke, including microglia, neutrophils, monocytes, lymphocytes, and astrocytes. Additionally, we have also highlighted the recent progress in various treatments for ischemic stroke, particularly in the field of stem cell therapy. Overall, understanding the complex interactions between inflammation and ischemic stroke can provide valuable insights for developing treatment strategies and improving patient outcomes. Stem cell therapy may potentially become an important component of ischemic stroke treatment.

Nanoparticle-neutrophils interactions for autoimmune regulation

Neutrophils play an essential role as 'first responders' in the immune response, necessitating many immune-modulating capabilities. Chronic, unresolved inflammation is heavily implicated in the progression and tissue-degrading effects of autoimmune disease. Neutrophils modulate disease pathogenesis by interacting with the inflammatory and autoreactive cells through effector functions, including signaling, degranulation, and neutrophil extracellular traps (NETs) release. Since the current gold standard systemic glucocorticoid administration has many drawbacks and side effects, targeting neutrophils in autoimmunity provides a new approach to developing therapeutics. Nanoparticles enable targeting of specific cell types and controlled release of a loaded drug cargo. Thus, leveraging nanoparticle properties and interactions with neutrophils provides an exciting new direction toward novel therapies for autoimmune diseases. Additionally, recent work has utilized neutrophil properties to design novel targeted particles for delivery into previously inaccessible areas. Here, we outline nanoparticle-based strategies to modulate neutrophil activity in autoimmunity, including various nanoparticle formulations and neutrophil-derived targeting.

Non-Tumor Cells within the Tumor Microenvironment-The "Eminence Grise" of the Glioblastoma Pathogenesis and Potential Targets for Therapy

Glioblastoma (GBM) is the most common malignancy of the central nervous system in adults. GBM has high levels of therapy failure and its prognosis is usually dismal. The phenotypic heterogeneity of the tumor cells, dynamic complexity of non-tumor cell populations within the GBM tumor microenvironment (TME), and their bi-directional cross-talk contribute to the challenges of current therapeutic approaches. Herein, we discuss the etiology of GBM, and describe several major types of non-tumor cells within its TME, their impact on GBM pathogenesis, and molecular mechanisms of such an impact. We also discuss their value as potential therapeutic targets or prognostic biomarkers, with reference to the most recent works on this subject. We conclude that unless all "key player" populations of non-tumor cells within the TME are considered, no breakthrough in developing treatment for GBM can be achieved.

Neutrophils bearing adhesive polymer micropatches as a drug-free cancer immunotherapy

Tumour-associated neutrophils can exert antitumour effects but can also assume a pro-tumoural phenotype in the immunosuppressive tumour microenvironment. Here we show that neutrophils can be polarized towards the antitumour phenotype by discoidal polymer micrometric 'patches' that adhere to the neutrophils' surfaces without being internalized. Intravenously administered micropatch-loaded neutrophils accumulated in the spleen and in tumour-draining lymph nodes, and activated splenic natural killer cells and T cells, increasing the accumulation of dendritic cells and natural killer cells. In mice bearing subcutaneous B16F10 tumours or orthotopic 4T1 tumours, intravenous injection of the micropatch-loaded neutrophils led to robust systemic immune responses, a reduction in tumour burden and improvements in survival rates. Micropatch-activated neutrophils combined with the checkpoint inhibitor anti-cytotoxic T-lymphocyte-associated protein 4 resulted in strong inhibition of the growth of B16F10 tumours, and in complete tumour regression in one-third of the treated mice. Micropatch-loaded neutrophils could provide a potent, scalable and drug-free approach for neutrophil-based cancer immunotherapy.

Altered peripheral blood leukocyte subpopulations, function, and gene expression in children with Down syndrome: implications for respiratory tract infection

OBJECTIVES

We tested the hypothesis that aberrant expression of Hsa21-encoded interferon genes in peripheral blood immune cells would correlate to immune cell dysfunction in children with Down syndrome (DS).

STUDY DESIGN

We performed flow cytometry to quantify peripheral blood leukocyte subtypes and measured their ability to migrate and phagocytose. In matched samples, we measured gene expression levels for constituents of interferon signaling pathways. We screened 49 children, of which 29 were individuals with DS.

RESULTS

We show that the percentages of two peripheral blood myeloid cell subtypes (alternatively-activated macrophages and low-density granulocytes) in children with DS differed significantly from typical children, children with DS circulate a very different pattern of cytokines vs. typical individuals, and higher expression levels of type III interferon receptor Interleukin-10Rb in individuals with DS correlated with reduced migratory and phagocytic capacity of macrophages.

CONCLUSIONS

Increased susceptibility to severe and chronic infection in children with DS may result from inappropriate numbers and subtypes of immune cells that are phenotypically and functionally altered due to trisomy 21 associated interferonopathy.

Targeting the chromatin structural changes of antitumor immunity

Epigenomic imbalance drives abnormal transcriptional processes, promoting the onset and progression of cancer. Although defective gene regulation generally affects carcinogenesis and tumor suppression networks, tumor immunogenicity and immune cells involved in antitumor responses may also be affected by epigenomic changes, which may have significant implications for the development and application of epigenetic therapy, cancer immunotherapy, and their combinations. Herein, we focus on the impact of epigenetic regulation on tumor immune cell function and the role of key abnormal epigenetic processes, DNA methylation, histone post-translational modification, and chromatin structure in tumor immunogenicity, and introduce these epigenetic research methods. We emphasize the value of small-molecule inhibitors of epigenetic modulators in enhancing antitumor immune responses and discuss the challenges of developing treatment plans that combine epigenetic therapy and immunotherapy through the complex interaction between cancer epigenetics and cancer immunology.

Immature neutrophils in cord blood exert increased expression of genes associated with antimicrobial function

Introduction

The immune systems of both the mother and the newborn face significant challenges during birth. Proper immune regulation after birth is essential for the survival of neonates. Numerous studies have demonstrated that the neonatal immune system is relatively immature, particularly in its adaptive arm, placing the primary responsibility for immune surveillance on innate immunity.

Methods

Given the significant role of neutrophils in protecting the neonate after birth, we conducted a study investigating the properties of neutrophils in newborn cord blood using various methodological approaches.

Results

Our findings demonstrate the presence of immature low-density neutrophils in the cord blood, which are likely responsible for the observed elevated expression of genes coding for proteins essential to antimicrobial response, including myeloperoxidase, neutrophils elastase, and defensins.

Discussion

We propose that these cells function normally and support the protection of newborns early after birth. Furthermore, our results suggest that the mode of delivery might significantly influence the programming of neutrophil function. The presented findings emphasize the importance of distinct neutrophil subpopulations in neonatal immunity and their potential impact on early postnatal health.

Neutrophil Extracellular Traps in Tumors and Potential Use of Traditional Herbal Medicine Formulations for Its Regulation

Neutrophil extracellular traps (NETs) are extracellular fibers composed of deoxyribonucleic acid (DNA) and decorated proteins produced by neutrophils. Recently, NETs have been associated with the development of many diseases, including tumors. Herein, we reviewed the correlation between NETs and tumors. In addition, we detailed active compounds from traditional herbal medicine formulations that inhibit NETs, related nanodrug delivery systems, and antibodies that serve as "guiding moieties" to ensure targeted delivery to NETs. Furthermore, we discussed the strategies used by pathogenic microorganisms to evade NETs.

Tumor-associated neutrophils suppress CD8+ T cell immunity in urothelial bladder carcinoma through the COX-2/PGE2/IDO1 Axis

BACKGROUND

Many urothelial bladder carcinoma (UBC) patients don't respond to immune checkpoint blockade (ICB) therapy, possibly due to tumor-associated neutrophils (TANs) suppressing lymphocyte immune response.

METHODS

We conducted a meta-analysis on the predictive value of neutrophil-lymphocyte ratio (NLR) in ICB response and investigated TANs' role in UBC. We used RNA-sequencing, HALO spatial analysis, single-cell RNA-sequencing, and flow cytometry to study the impacts of TANs and prostaglandin E2 (PGE2) on IDO1 expression. Animal experiments evaluated celecoxib's efficacy in targeting PGE2 synthesis.

RESULTS

Our analysis showed that higher TAN infiltration predicted worse outcomes in UBC patients receiving ICB therapy. Our research revealed that TANs promote IDO1 expression in cancer cells, resulting in immunosuppression. We also found that PGE2 synthesized by COX-2 in neutrophils played a key role in upregulating IDO1 in cancer cells. Animal experiments showed that targeting PGE2 synthesis in neutrophils with celecoxib enhanced the efficacy of ICB treatment.

CONCLUSIONS

TAN-secreted PGE2 upregulates IDO1, dampening T cell function in UBC. Celecoxib targeting of PGE2 synthesis represents a promising approach to enhance ICB efficacy in UBC.

A GPCR-neuropeptide axis dampens hyperactive neutrophils by promoting an alternative-like polarization during bacterial infection

The notion that neutrophils exist as a homogeneous population is being replaced with the knowledge that neutrophils adopt different functional states. Neutrophils can have a pro-inflammatory phenotype or an anti-inflammatory state, but how these states are regulated remains unclear. Here, we demonstrated that the neutrophil-expressed G-protein-coupled receptor (GPCR) Mrgpra1 is a negative regulator of neutrophil bactericidal functions. Mrgpra1-mediated signaling was driven by its ligand, neuropeptide FF (NPFF), which dictated the balance between pro- and anti-inflammatory programming. Specifically, the Mrgpra1-NPFF axis counter-regulated interferon (IFN) γ-mediated neutrophil polarization during acute lung infection by favoring an alternative-like polarization, suggesting that it may act to balance overzealous neutrophilic responses. Distinct, cross-regulated populations of neutrophils were the primary source of NPFF and IFNγ during infection. As a subset of neutrophils at steady state expressed NPFF, these findings could have broad implications in various infectious and inflammatory diseases. Therefore, a neutrophil-intrinsic pathway determines their cellular fate, function, and magnitude of infection.

Characterizing the Inflammatory Profile of Neutrophil-Rich Triple-Negative Breast Cancer

Breast cancer (BC) is one of the most common types of cancer in women in the United Arab Emirates. Immunogenic tumours, such as triple-negative breast cancer (TNBC), show increased neutrophil infiltration, which is associated with poor prognosis and limited efficacy of immunotherapy. This study aims to investigate in vitro the bidirectional effect of neutrophils on metastatic TNBC (MDA-MB-231) compared to less-metastatic luminal breast cancer (MCF-7) cell lines. We found that BC cells or their conditioned medium (CM) reduced the viability of neutrophil-like cells (HL60). This was supported by increased cellular stress and NETosis in differentiated HL60 cells (dHL60) upon exposure to MDA-MB-231 compared to MCF-7-CM using nucleic acid staining essays. Flow cytometry showed comparable expression of inflammatory markers by polymorphonuclear cells (PMN) when treated with MDA-MB-231-CM and standard polarizing cocktails. Furthermore, MDA-MB-231-CM triggered an inflammatory pattern with evidence of stronger adhesion (CD62L) and degranulation (CD11b and CD66b) phenotypes. The proinflammatory polarization of dHL60 by MDA-MB-231-CM was additionally confirmed by the elevated CD54 expression, myeloperoxidase, and CD11b protein levels, which matched an increased transwell migratory capacity. In conclusion, BC might use neutrophils to their benefit through NETosis and complement system activation, which makes this crosstalk a potential mechanism for understanding tumour progression.

Neutrophils in HNSCC Can Be Associated with Both a Worse or Favorable Prognosis

The prognostic significance of tumor-infiltrating neutrophils in head and neck squamous cell carcinoma (HNSCC) is poorly understood. It is unclear how the presence of neutrophils affects prognosis due to their polarization into cytotoxic N1 or immunosuppressive N2. Therefore, we determined the number of CD66b+ neutrophil granulocytes separately in the stromal and epithelial compartments in cancer tissues from 397 patients with HNSCC. Tumor samples from six historical patient groups were processed into tissue microarrays and stained immunohistochemically. In total, 21.9% were HPV positive (p16+). Neutrophil counts were much lower in the stromal compartment (372 ± 812) than in the epithelial cancer compartment (1040 ± 1477) (p < 0.001), with large differences between groups. In three groups with high neutrophil infiltration, high rates were associated with a favorable prognosis, whereas in two groups, high rates were a negative prognostic factor. In p16- oropharyngeal and hypopharyngeal cancer high infiltration was associated with a favorable prognosis. Cancers with an exclusion of neutrophils in the epithelial compartment were associated with improved prognosis. In oropharyngeal and hypopharyngeal HPV-negative cancer high neutrophil infiltration rates were clearly associated with prolonged survival. Neutrophil granulocytes in HNSCC may contribute to a favorable or unfavorable prognosis.

Innate and adaptive immune-directed tumour microenvironment in pancreatic ductal adenocarcinoma

One of the most deadly and aggressive cancers in the world, pancreatic ductal adenocarcinoma (PDAC), typically manifests at an advanced stage. PDAC is becoming more common, and by the year 2030, it is expected to overtake lung cancer as the second greatest cause of cancer-related death. The poor prognosis can be attributed to a number of factors, including difficulties in early identification, a poor probability of curative radical resection, limited response to chemotherapy and radiotherapy, and its immunotherapy resistance. Furthermore, an extensive desmoplastic stroma that surrounds PDAC forms a mechanical barrier that prevents vascularization and promotes poor immune cell penetration. Phenotypic heterogeneity, drug resistance, and immunosuppressive tumor microenvironment are the main causes of PDAC aggressiveness. There is a complex and dynamic interaction between tumor cells in PDAC with stromal cells within the tumour immune microenvironment. The immune suppressive microenvironment that promotes PDAC aggressiveness is contributed by a range of cellular and humoral factors, which itself are modulated by the cancer. In this review, we describe the role of innate and adaptive immune cells, complex tumor microenvironment in PDAC, humoral factors, innate immune-mediated therapeutic advances, and recent clinical trials in PDAC.

Silenced-C5ar1 improved multiple organ injury in sepsis rats via inhibiting neutrophil extracellular trap

Sepsis has a systemic inflammatory response syndrome caused by infection. While neutrophils play contradictory roles in different stages of sepsis. Neutrophils have been proven to play an antibacterial role by producing neutrophil extracellular traps (NETs). Although the NET is beneficial to bacteria resistance, abnormal NET increases tissue damage. The complement C5a receptor 1 (C5ar1) is a gene related to strong inflammatory reactions and is found to be associated with inflammatory factors. This study found that there were 45 down-regulated genes and 704 up-regulated genes in sepsis rats by transcriptome sequencing. And those genes were significantly related to inflammation and immunity by GO and KEGG enrichment analysis involving the chemokine signaling pathway, the Toll-like receptor (TLR) signaling pathway, and the Fc gamma R-mediated phagocytosis. Additionally, the C5ar1 gene was significantly upregulated with interesting potential in sepsis and used for further study. This study used cecum ligation and puncture (CLP) rats that were respectively injected intravenously with PBS or the lentivirus vector to explore the effect of C5ar1 on CLP rats. It demonstrated that silenced- C5ar1 inhibited the ALT, AST, BUN, and CREA levels, improved the lung and spleen injury, and reduced the TNF-α, IL-6, IL-1β, IL-10, cf-DNA, and cfDNA/MPO levels. Additionally, silenced C5ar1 inhibited the TLR2, TLR4, and peptidylarginine deiminase 4 expression levels, which suggested the improvement of silenced C5ar1 on sepsis via inhibiting NETs and the TLR signaling pathway. This study provides a basis and new direction for the study of treatment on sepsis.

Bacteria colonization in tumor microenvironment creates a favorable niche for immunogenic chemotherapy

The tumor microenvironment (TME) presents differential selective pressure (DSP) that favors the growth of cancer cells, and monovalent therapy is often inadequate in reversing the cancer cell dominance in the TME. In this work, we introduce bacteria as a foreign species to the TME and explore combinatorial treatment strategies to alter DSP for tumor eradication. We show that cancer-selective chemotherapeutic agents and fasting can provide a strong selection pressure against tumor growth in the presence of bacteria. Moreover, we show that an immunogenic drug (oxaliplatin), but not a non-immunogenic one (5-FU), synergizes with the bacteria to activate both the innate and adaptive immunity in the TME, resulting in complete tumor remission and a sustained anti-tumor immunological memory in mice. The combination of oxaliplatin and bacteria greatly enhances the co-stimulatory and antigen-presenting molecules on antigen-presenting cells, which in turn bridge the cytotoxic T cells for cancer-cell killing. Our findings indicate that rational combination of bacterial therapy and immunogenic chemotherapy can promote anticancer immunity against the immunosuppressive TME.

miR-146a inhibits ovarian tumor growth in vivo via targeting immunosuppressive neutrophils and enhancing CD8+ T cell infiltration

Immunotherapies have emerged as promising strategies for cancer treatment. However, existing immunotherapies have poor activity in high-grade serous ovarian cancer (HGSC) due to the immunosuppressive tumor microenvironment and the associated low tumoral CD8+ T cell (CTL) infiltration. Through multiple lines of evidence, including integrative analyses of human HGSC tumors, we have identified miR-146a as a master regulator of CTL infiltration in HGSC. Tumoral miR-146a expression is positively correlated with anti-cancer immune signatures in human HGSC tumors, and delivery of miR-146a to tumors resulted in significant reduction in tumor growth in both ID8-p53-/- and IG10 murine HGSC models. Increasing miR-146a expression in tumors improved anti-tumor immune responses by decreasing immune suppressive neutrophils and increasing CTL infiltration. Mechanistically, miR-146a targets IL-1 receptor-associated kinase 1 and tumor necrosis factor receptor-associated factor 6 adaptor molecules of the transcription factor nuclear factor κB signaling pathway in ID8-p53-/- cells and decreases production of the downstream neutrophil chemoattractant, C-X-C motif chemokine ligand 1. In addition to HGSC, tumoral miR-146a expression also correlates strongly with CTL infiltration in other cancer types including thyroid, prostate, breast, and adrenocortical cancers. Altogether, our findings highlight the ability of miR-146a to overcome immune suppression and improve CTL infiltration in tumors.

How Neutrophils Shape the Immune Response: Reassessing Their Multifaceted Role in Health and Disease

Neutrophils are the most abundant of the circulating immune cells and are the first to be recruited to sites of inflammation. Neutrophils are a heterogeneous group of immune cells from which are derived extracellular traps (NETs), reactive oxygen species, cytokines, chemokines, immunomodulatory factors, and alarmins that regulate the recruitment and phenotypes of neutrophils, macrophages, dendritic cells, T cells, and B cells. In addition, cytokine-stimulated neutrophils can express class II major histocompatibility complex and the internal machinery necessary for successful antigen presentation to memory CD4+ T cells. This may be relevant in the context of vaccine memory. Neutrophils thus emerge as orchestrators of immune responses that play a key role in determining the outcome of infections, vaccine efficacy, and chronic diseases like autoimmunity and cancer. This review aims to provide a synthesis of current evidence as regards the role of these functions of neutrophils in homeostasis and disease.

Cancer Stem Cells in Colorectal Cancer: Implications for Targeted Immunotherapies

PURPOSE

Colorectal cancers are composed of heterogeneous cell populations in the concepts of genetic and functional degrees that among them cancer stem cells are identified with their self-renewal and stemness capability mediating primary tumorigenesis, metastasize, therapeutic resistance, and tumor recurrence. Therefore, understanding the key mechanisms of stemness in colorectal cancer stem cells (CRCSCs) provides opportunities to discover new treatments or improve existing therapeutic regimens.

METHODS

We review the biological significance of stemness and the results of potential CRCSC-based targeted immunotherapies. Then, we pointed out the barriers to targeting CRCSCs in vivo and highlight new strategies based on synthetic and biogenic nanocarriers for the development of future anti-CRCSC trials.

RESULTS

The CSCs' surface markers, antigens, neoantigens, and signaling pathways supportive CRCSCs or immune cells that are interacted with CRCSCs could be targeted by immune monotherapy or in formulation with developed nanocarriers to overcome the resistant mechanisms in immune evader CRCSCs.

CONCLUSION

Identification molecular and cellular cues supporting stemness in CRCSCs and their targeting by nanoimmunotherpy can improve the efficacy of existed therapies or explore novel therapeutic options in future.

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

BACKGROUND

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

RESULTS

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

CONCLUSIONS

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

Integrated single-cell and bulk RNA sequencing revealed the molecular characteristics and prognostic roles of neutrophils in pancreatic cancer

Pancreatic cancer, one of the most prevalent tumors of the digestive system, has a dismal prognosis. Cancer of the pancreas is distinguished by an inflammatory tumor microenvironment rich in fibroblasts and different immune cells. Neutrophils are important immune cells that infiltrate the microenvironment of pancreatic cancer tumors. The purpose of this work was to examine the complex mechanism by which neutrophils influence the carcinogenesis and development of pancreatic cancer and to construct a survival prediction model based on neutrophil marker genes. We incorporated the GSE111672 dataset, comprising RNA expression data from 27,000 cells obtained from 3 patients with PC, and conducted single-cell data analysis. Thorough investigation of pancreatic cancer single-cell RNA sequencing data found 350 neutrophil marker genes. Using The Cancer Genome Atlas (TCGA), GSE28735, GSE62452, GSE57495, and GSE85916 datasets to gather pancreatic cancer tissue transcriptome data, and consistent clustering was used to identify two categories for analyzing the influence of neutrophils on pancreatic cancer. Using the Random Forest algorithm and Cox regression analysis, a survival prediction model for pancreatic cancer was developed, the model showed independent performance for survival prognosis, clinic pathological features, immune infiltration, and drug sensitivity. Multivariate Cox analysis findings revealed that the risk scores derived from predictive models is independent prognostic markers for pancreatic patients. In conclusion, based on neutrophil marker genes, this research created a molecular typing and prognostic grading system for pancreatic cancer, this system was very accurate in predicting the prognosis, tumor immune microenvironment status, and pharmacological treatment responsiveness of pancreatic cancer patients.

Identification of Breast Cancer LCK Proto-Oncogene as a Master Regulator of TNBC Neutrophil Enrichment and Polarization

The role of neutrophils in breast cancer shows that the N1 proinflammatory subtype can suppress and attack the tumor. In contrast, the N2 pro-tumor subtype aids the tumor in its survival, progression, and metastasis. Recently, more focus has been directed to the role of innate myeloid cells, specifically neutrophils, in regulating the responses of lymphoid populations both in the progression of cancer and in response to therapy. However, the exact crosstalk between breast cancer cells and neutrophils is poorly understood. In this work, we used in-silico assays to investigate the role of the bidirectional effect of neutrophils on metastatic TNBC. Our reanalysis of publicly available data reveals that most TNBC's classified within the CE2 subtype are leukocyte-poor and have four major cell types in their ecotypes: dendritic cells, macrophages, fibroblasts, and epithelial cells. Further immune deconvolution of these patients revealed that a few cells significantly differed between groups, including macrophages, neutrophils, and T cells. All BC showed lower infiltrating neutrophils compared to healthy surrounding tissue. Treated TNBCs improved the count of infiltrating neutrophils in TNBC. Most TNBC patients have a unique CE2 ecotype, characterized by more basal-like epithelial cells, more neutrophils, and fewer mononuclear lymphocytes (B cells, macrophages M1, T cell CD4+ (non-regulatory), and T cell CD8+ and T regs). This can be related to our finding that CE2 TNBCs are characterized by a lower LCK and higher ERBB2, and their top DEGs are related to leukocyte activation and NFKB pathway.

The Role of Cytokines in Neutrophil Development, Tissue Homing, Function and Plasticity in Health and Disease

Neutrophils are crucial innate immune cells and comprise 50-70% of the white blood cell population under homeostatic conditions. Upon infection and in cancer, blood neutrophil numbers significantly increase because of the secretion of various chemo- and cytokines by, e.g., leukocytes, pericytes, fibroblasts and endothelial cells present in the inflamed tissue or in the tumor microenvironment (TME). The function of neutrophils in cancer has recently gained considerable attention, as they can exert both pro- and anti-tumorigenic functions, dependent on the cytokine milieu present in the TME. Here, we review the effect of cytokines on neutrophil development, tissue homing, function and plasticity in cancer and autoimmune diseases as well as under physiological conditions in the bone marrow, bloodstream and various organs like the spleen, kidney, liver, lung and lymph nodes. In addition, we address several promising therapeutic options, such as cytokine therapy, immunocytokines and immunotherapy, which aim to exploit the anti-tumorigenic potential of neutrophils in cancer treatment or block excessive neutrophil-mediated inflammation in autoimmune diseases.

Pro-Tumorigenic and Thrombotic Activities of Platelets in Lung Cancer

Aside from their key protective roles in hemostasis and innate immunity, platelets are now recognized as having multifaceted, adverse roles in the pathogenesis, progression and outcome of many types of human malignancy. The most consistent and compelling evidence in this context has been derived from the notable association of elevated circulating platelet counts with the onset and prognosis of various human malignancies, particularly lung cancer, which represents the primary focus of the current review. Key topics include an overview of the association of lung cancer with the circulating platelet count, as well as the mechanisms of platelet-mediated, pro-tumorigenic immunosuppression, particularly the role of transforming growth factor beta 1. These issues are followed by a discussion regarding the pro-tumorigenic role of platelet-derived microparticles (PMPs), the most abundant type of microparticles (MPs) in human blood. In this context, the presence of increased levels of PMPs in the blood of lung cancer patients has been associated with tumor growth, invasion, angiogenesis and metastasis, which correlate with disease progression and decreased survival times. The final section of the review addresses, firstly, the role of cancer-related platelet activation and thrombosis in the pathogenesis of secondary cardiovascular disorders and the associated mortality, particularly in lung cancer, which is second only to disease progression; secondly, the review addresses the potential role of antiplatelet agents in the adjunctive therapy of cancer.

Schlafen4+-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases

Introduction

MDSCs express SCHLAFEN 4 (SLFN4) in Helicobacter-infected stomachs coincident with spasmolytic polypeptide-expressing metaplasia (SPEM), a precursor of gastric cancer. We aimed to characterize SLFN4+ cell identity and the role of Slfn4 in these cells.

Methods

Single-cell RNA sequencing was performed on immune cells sorted from PBMCs and stomachs prepared from uninfected and 6-month H. felis-infected mice. Knockdown of Slfn4 by siRNA or PDE5/6 inhibition by sildenafil were performed in vitro. Intracellular ATP/GTP levels and GTPase activity of immunoprecipitated Slfn4 complexes were measured using the GTPase-Glo assay kit. The intracellular level of ROS was quantified by the DCF-DA fluorescent staining, and apoptosis was determined by cleaved Caspase-3 and Annexin V expression. Gli1CreERT2 x Slfn4 fl/fl mice were generated and infected with H. felis. Sildenafil was administered twice over 2 weeks by gavaging H. felis infected mice ~4 months after inoculation once SPEM had developed.

Results

Slfn4 was highly induced in both monocytic and granulocytic MDSCs from infected stomachs. Both Slfn4 +-MDSC populations exhibited strong transcriptional signatures for type-I interferon responsive GTPases and exhibited T cell suppressor function. SLFN4-containing protein complexes immunoprecipitated from myeloid cell cultures treated with IFNa exhibited GTPase activity. Knocking down Slfn4 or PDE5/6 inhibition with sildenafil blocked IFNa induction of GTP, SLFN4 and NOS2. Moreover, IFNa induction of Slfn +-MDSC function was inhibited by inducing their reactive oxygen species (ROS) production and apoptosis through protein kinase G activation. Accordingly, in vivo disruption of Slfn4 in Gli1CreERT2 x Slfn4 fl/fl mice or pharmacologic inhibition by sildenafil after Helicobacter infection also suppressed SLFN4 and NOS2, reversed T cell suppression and mitigated SPEM development.

Conclusion

Taken together, SLFN4 regulates the activity of the GTPase pathway in MDSCs and precludes these cells from succumbing to the massive ROS generation when they acquire MDSC function.

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

INTRODUCTION

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

METHODOLOGY

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

RESULTS

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

CONCLUSION

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

Bladder cancer patients have increased NETosis and impaired DNaseI-mediated NET degradation that can be therapeutically restored in vitro

Background

Neutrophils, key players of the immune system, also promote tumor development through the formation of neutrophil extracellular traps (NETs) in a process called NETosis. NETs are extracellular networks of DNA, histones and cytoplasmic and granular proteins (calprotectin, myeloperoxidase, elastase, etc.) released by neutrophils upon activation. NETs regulate tumor growth while promoting angiogenesis and invasiveness, and tumor cells also stimulate NETosis. Although NETosis seems to be increased in cancer patients, an increase of NETs in plasma may also be mediated by an impaired degradation by plasma DNaseI, as evidenced in several immunological disorders like lupus nephritis. However, this has never been evidenced in bladder cancer (BC) patients. Herein, we aimed to evaluate the occurrence of increased NETosis in plasma and tumor tissue of BC patients, to ascertain whether it is mediated by a reduced DNaseI activity and degradation, and to in vitro explore novel therapeutic interventions.

Methods

We recruited 71 BC patients from whom we obtained a plasma sample before surgery and a formalin-fixed paraffin embedded tumor tissue sample, and 64 age- and sex-matched healthy controls from whom we obtained a plasma sample. We measured NETs markers (cell-free fDNA, calprotectin, nucleosomes and neutrophil elastase) and the DNaseI activity in plasma with specific assays. We also measured NETs markers in BC tissue by immunofluorescence. Finally, we evaluated the ability of BC and control plasma to degrade in vitro-generated NETs, and evaluated the performance of the approved recombinant human DNaseI (rhDNaseI, Dornase alfa, Pulmozyme^®, Roche) to restore the NET-degradation ability of plasma. In vitro experiments were performed in triplicate. Statistical analysis was conducted with Graphpad (v.8.0.1).

Results

NETosis occurs in BC tissue, more profusely in the muscle-invasive subtype (P<0.01), that with the worst prognosis. Compared to controls, BC patients had increased NETosis and a reduced DNaseI activity in plasma (P<0.0001), which leads to an impairment to degrade NETs (P<0.0001). Remarkably, this can be therapeutically restored with rhDNaseI to the level of healthy controls.

Conclusion

To the best of our knowledge, this is the first report demonstrating that BC patients have an increased NETosis systemically and in the tumor microenvironment, in part caused by an impaired DNaseI-mediated NET degradation. Remarkably, this defect can be therapeutically restored in vitro with the approved Dornase alfa, thus Pulmozyme^® could become a potential therapeutic tool to locally reduce BC progression.

Genetic susceptibility for autoimmune diseases and white blood cell count

Some autoimmune (AI) conditions affect white blood cell (WBC) counts. Whether a genetic predisposition to AI disease associates with WBC counts in populations expected to have low numbers of AI cases is not known. We developed genetic instruments for 7 AI diseases using genome-wide association study summary statistics. Two-sample inverse variance weighted regression (IVWR) was used to determine associations between each instrument and WBC counts. Effect size represents change in transformed WBC counts per change in log odds-ratio of the disease. For AI diseases with significant associations by IVWR, polygenic risk scores (PRS) were used to test for associations with measured WBC counts in individuals of European ancestry in a community-based (ARIC, n = 8926), and a medical-center derived cohort (BioVU, n = 40,461). The IVWR analyses revealed significant associations between 3 AI diseases and WBC counts: systemic lupus erythematous (Beta = - 0.05 [95% CI, - 0.06, - 0.03]), multiple sclerosis (Beta =  - 0.06 [- 0.10, - 0.03]), and rheumatoid arthritis (Beta = 0.02 [0.01, 0.03]). PRS for these diseases showed associations with measured WBC counts in ARIC and BioVU. Effect sizes tended to be larger among females, consistent with the known higher prevalence of these diseases among this group. This study shows that genetic predisposition to systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis was associated with WBC counts, even in populations expected to have very low numbers of disease cases.

Response of mesenchymal stem cells to surface topography of scaffolds and the underlying mechanisms

Mesenchymal stem/stromal cells (MSCs) serve as essential components of regenerative medicine. Their destiny is influenced by the interaction of the cells with the external environment. In addition to the biochemical cues in a microenvironment, physical cues of the topography of the surrounding materials such as the extracellular matrix emerge as a crucial regulator of stem cell destiny and function. With recent advances in technologies of materials production and surface modification, surfaces with micro/nanotopographical characteristics can be fabricated to mimic the micro/nanoscale mechanical stimuli of the extracellular matrix environment and regulate the biological behavior of cells. Understanding the interaction of cells with the topography of a surface is conducive to the control of stem cell fate for application in regenerative medicine. However, the mechanisms by which topography affects the biological behavior of stem cells have not been fully elucidated. This review will present the effects of surface topography at the nano/micrometer scale on stem cell adhesion, morphology, proliferation, migration, and differentiation. It also focuses on discussing current theories about the sensing and recognition of surface topology cues, the transduction of the extracellular cues into plasma, and the final activation of related signaling pathways and downstream gene expression in MSCs. These insights will provide a theoretical basis for the future design of biomaterial scaffolds for application in regenerative medicine and tissue engineering.

The Outcome of COVID-19 Infection in Patients With Gastrointestinal Diseases: An Experience at a Tertiary Center

OBJECTIVE

Observing the impact of the coronavirus disease 2019 (COVID-19) pandemic on digestive diseases in hospitalized patients at the Department of Gastroenterology-Hepatology in "Mother Teresa" University Hospital Center (UHC),Tirana.

METHODS

This retrospective study was carried out from June 2020 to December 2021 involving 41 cases of patients >18 years who were positive for COVID-19 infection detected by RT-PCR (Reverse Transcription-Polymerase Chain Reaction) assays of nasopharyngeal swab specimens. The severity of COVID-19 infection was evaluated by hematological/biochemical parameters, blood oxygenation/need for oxygen, radiological data on pulmonary CT imaging.

RESULTS

Out of 2527 hospitalized cases, 1.6% (41) were positive for the infection. The average age was 60.05 +/- 15.008 years. The group of age with more patients (48.8%) was 41-60 years. Infected males were higher than females (p<0.001). Out of the total, 21% were vaccinated at the diagnosis. Most patients came from urban areas, more than a half from the capital. Frequency of the digestive diseases was: cirrhosis 31.7%, pancreatitis 21.9%, alcoholic liver disease 21.9%, gastrointestinal hemorrhage 19.5%, digestive cancer 14.6%, biliary diseases 7.3%, inflammatory bowel disease (IBD) 2.4%, other digestive diseases 4.8%. Fever (90%) and fatigue (78.04%) were the dominant clinical signs.  Biochemical and hematological parameters showed elevation of average value of aspartate amino transferase (AST), alanine transaminase (ALT) (AST>ALT, p<0.001), and bilirubin in all the patients. Higher levels of creatinine and significantly predictive value of systemic inflammation indices NLR (neutrophil to lymphocyte ratio ) and MLR (monocyte to lymphocyte ratio) were found in the fatality cases. Patients with cirrhosis had more severe form of COVID-19, lower blood oxygenation and needed treatment by O₂-therapy (p<0.046). Death rate was 12%. A strong correlation was found between the need for O₂-therapy and deaths (p<0.001) and between characteristic findings for COVID-19 in pulmonary CT imaging and low blood oxygenation (p<0.003).

CONCLUSION

Comorbidity with chronic diseases, such as liver cirrhosis, has an important impact on the severity and mortality of the patients with COVID-19 infection. Inflammatory indices, such as NLR (neutrophil to lymphocyte ratio) and MLR (monocyte to lymphocyte ratio), are useful tools in predicting the evolution toward severe forms of the disease.

Hyaluronic Acid in Synovial Fluid Prevents Neutrophil Activation in Spondyloarthritis

Spondyloarthritis (SpA) patients suffer from joint inflammation resulting in tissue damage, characterized by the presence of numerous neutrophils in the synovium and synovial fluid (SF). As it is yet unclear to what extent neutrophils contribute to the pathogenesis of SpA, we set out to study SF neutrophils in more detail. We analyzed the functionality of SF neutrophils of 20 SpA patients and 7 disease controls, determining ROS production and degranulation in response to various stimuli. In addition, the effect of SF on neutrophil function was determined. Surprisingly, our data show that SF neutrophils in SpA patients have an inactive phenotype, despite the presence of many neutrophil-activating stimuli such as GM-CSF and TNF in SF. This was not due to exhaustion as SF neutrophils readily responded to stimulation. Therefore, this finding suggests that one or more inhibitors of neutrophil activation may be present in SF. Indeed, when blood neutrophils from healthy donors were activated in the presence of increasing concentrations of SF from SpA patients, degranulation and ROS production were dose-dependently inhibited. This effect was independent of diagnosis, gender, age, and medication in the patients from which the SF was isolated. Treatment of SF with the enzyme hyaluronidase strongly reduced the inhibitory effect of SF on neutrophil activation, indicating that hyaluronic acid that is present in SF may be an important factor in preventing SF neutrophil activation. This finding provides novel insights into the role of soluble factors in SF regulating neutrophil function and may lead to the development of novel therapeutics targeting neutrophil activation via hyaluronic acid or associated pathways.

Fashionable, but What is Their Real Clinical Usefulness? NLR, LMR, and PLR as a Promising Indicator in Colorectal Cancer Prognosis: A Systematic Review

The link between inflammation and cancer is still an attractive subject of many studies because systemic inflammatory response has been proven to play a pivotal role in cancer progression and metastasis. The strongest relationship between chronic inflammation and cancer development is observed in colorectal cancer (CRC). The evaluation of ratios derived from the routinely performed inflammatory biomarkers shows limited performances and limited clinical utility when individually used as prognostic factors for patients with CRC. In this review, we would like to summarize the latest knowledge about the diagnostic utility of systemic inflammatory ratios: neutrophil/lymphocyte (NLR), lymphocyte/monocyte (LMR), and platelet/lymphocyte (PLR) in CRC. We focused on the papers that assessed the diagnostic utility of blood cell parameters on the basis of the area under the ROC curve published in the recent 6 years. Identification of biomarkers that are significantly associated with prognostic in cancer would help the selection of patients with a high risk of poor outcomes.

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

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

Single-Cell Transcriptomic Profiles of Lung Pre-Metastatic Niche Reveal Neutrophil and Lymphatic Endothelial Cell Roles in Breast Cancer

The establishment of a pre-metastatic niche (PMN) is critical for cancer metastasis. However, it remains unclear as to which phenotypes induce changes in the PMN. Single-cell transcriptomic profiling of all cells of the lung in cancer-bearing MMTV-PyVT mice revealed an increased infiltration of N2-type neutrophils and classical monocytes associated with chronic inflammation; notably, lung neutrophils isolated from mice with primary cancer exhibited similar N2-type phenotypes and expressed high levels of inflammatory and angiogenic factors. We also discovered a new cluster of Ki67-upregulated lymphatic endothelial cells (ECs) that activated several cell division-related pathways. Receptor-ligand interactions within the lung potentially mediated PMN formation; these were exemplified by the cross talk of lymphatic EC-N2-type neutrophil via S100A6. In vitro study revealed S100A6 impaired EC tight junction and increased the transendothelial migration of neutrophils. Our results highlight the molecular mechanisms that shape lung PMN and inspire preventive strategies for lung metastasis in breast cancer.

Neutrophil dynamics and inflammaging in acute ischemic stroke: A transcriptomic review

Stroke is among the leading causes of death and disability worldwide. Restoring blood flow through recanalization is currently the only acute treatment for cerebral ischemia. Unfortunately, many patients that achieve a complete recanalization fail to regain functional independence. Recent studies indicate that activation of peripheral immune cells, particularly neutrophils, may contribute to microcirculatory failure and futile recanalization. Stroke primarily affects the elderly population, and mortality after endovascular therapies is associated with advanced age. Previous analyses of differential gene expression across injury status and age identify ischemic stroke as a complex age-related disease. It also suggests robust interactions between stroke injury, aging, and inflammation on a cellular and molecular level. Understanding such interactions is crucial in developing effective protective treatments. The global stroke burden will continue to increase with a rapidly aging human population. Unfortunately, the mechanisms of age-dependent vulnerability are poorly defined. In this review, we will discuss how neutrophil-specific gene expression patterns may contribute to poor treatment responses in stroke patients. We will also discuss age-related transcriptional changes that may contribute to poor clinical outcomes and greater susceptibility to cerebrovascular diseases.

A missense variant in NCF1 is associated with susceptibility to unexplained recurrent spontaneous abortion

Unexplained recurrent spontaneous abortion (URSA) is a major concern in reproductive medicine. Neutrophil cytosolic factor 1 (NCF1) polymorphisms leading to low production of reactive oxygen species (ROS) are strongly associated with autoimmune diseases. We investigated the association of the missense single nucleotide polymorphism (SNP) rs201802880 (NCF1-339) in NCF1 with URSA and explored its function. We performed NCF1-339 SNP genotyping of samples from 152 Chinese patients with URSA and 72 healthy controls using nested PCR and TaqMan assays. ROS production and RELA (NF-κB subunit) expression in the blood of participants with different NCF1-339 genotypes were determined. The frequencies of the wild-type (GG) and mutant (GA) genotypes remarkably differed between the URSA and control groups. The mutant genotype was associated with an increased risk of recurrent abortion. Furthermore, ROS levels in the URSA group with the GG genotype were significantly higher than those in the group with the GA genotype (p < 0.05). RELA expression in URSA patients with the GA genotype was considerably higher than that in control individuals with the GG genotype. These findings indicate that mutations in NCF1 may increase the risk of URSA via the NADP/ROS/NF-κB signaling pathway, which has implications for the diagnosis and treatment of URSA.

Non-apoptotic activity of the mitochondrial protein SMAC/Diablo in lung cancer: Novel target to disrupt survival, inflammation, and immunosuppression

Mitochondrial SMAC/Diablo induces apoptosis by binding the inhibitor of apoptosis proteins (IAPs), thereby activating caspases and, subsequently, apoptosis. Previously, we found that despite its pro-apoptotic activity, SMAC/Diablo is overexpressed in cancer, and demonstrated that in cancer it possesses new essential and non-apoptotic functions that are associated with regulating phospholipid synthesis including modulating mitochondrial phosphatidylserine decarboxylase activity. Here, we demonstrate additional functions for SMAC/Diablo associated with inflammation and immunity. CRISPR/Cas9 SMAC/Diablo-depleted A549 lung cancer cells displayed inhibited cell proliferation and migration. Proteomics analysis of these cells revealed altered expression of proteins associated with lipids synthesis and signaling, vesicular transport and trafficking, metabolism, epigenetics, the extracellular matrix, cell signaling, and neutrophil-mediated immunity. SMAC-KO A549 cell-showed inhibited tumor growth and proliferation and activated apoptosis. The small SMAC-depleted “tumor” showed a morphology of alveoli-like structures, reversed epithelial-mesenchymal transition, and altered tumor microenvironment. The SMAC-lacking tumor showed reduced expression of inflammation-related proteins such as NF-kB and TNF-α, and of the PD-L1, associated with immune system suppression. These results suggest that SMAC is involved in multiple processes that are essential for tumor growth and progression. Thus, targeting SMAC’s non-canonical function is a potential strategy to treat cancer.

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

Background

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

Method

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

Results

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

Conclusions

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

Neutrophils: Musketeers against immunotherapy

Neutrophils, the most copious leukocytes in human blood, play a critical role in tumorigenesis, cancer progression, and immune suppression. Recently, neutrophils have attracted the attention of researchers, immunologists, and oncologists because of their potential role in orchestrating immune evasion in human diseases including cancer, which has led to a hot debate redefining the contribution of neutrophils in tumor progression and immunity. To make this debate fruitful, this review seeks to provide a recent update about the contribution of neutrophils in immune suppression and tumor progression. Here, we first described the molecular pathways through which neutrophils aid in cancer progression and orchestrate immune suppression/evasion. Later, we summarized the underlying molecular mechanisms of neutrophil-mediated therapy resistance and highlighted various approaches through which neutrophil antagonism may heighten the efficacy of the immune checkpoint blockade therapy. Finally, we have highlighted several unsolved questions and hope that answering these questions will provide a new avenue toward immunotherapy revolution.

Melanoma Stem Cells Educate Neutrophils to Support Cancer Progression

Simple Summary

In melanoma patients, poor prognosis often correlates with high presence of cancer-associated neutrophils, indicating that tumors can recruit these immune cells to specifically sustain their own development and progression. However, the role of cancer stem cells (CSCs) in this dialogue has not been elucidated yet. Our results revealed that melanoma SCs can reshape the immune microenvironment by triggering a pro-tumor N2 phenotype in neutrophils, which in turn are able to confer stemness properties to melanoma cells.

Abstract

Background: It is now well-established that cancer stem cells (CSCs) can support melanoma progression by reshaping the tumor immune microenvironment. However, the molecular mechanisms underlying the crosstalk between melanoma SCs and cancer-associated neutrophils have not been elucidated yet. Methods: The aim of the present study was to unravel the role of melanoma SCs in neutrophil polarization. HL60 neutrophil-like (dHL60) cells were treated with conditioned medium from A375 melanoma SCs (CSC-CM), and their phenotype was investigated. Results: We demonstrated that CSC-CM could specifically activate immune cells by increasing CD66b and CD11b expression. In particular, we revealed that A375 CSCs could release various soluble factors, namely TGF-β, IL-6, and IL-8, able to promote the recruitment of neutrophils and their switch toward an N2 phenotype characterized by the activation of ERK, STAT3, and P38 pathways and the overexpression of CXCR2 and NF-kB. Moreover, after exposure to CSC-CM, dHL60 cells exhibited enhanced ROS production and NET release, without undergoing cell death; increased secretion of MMP-9 and pro-inflammatory cytokines was also observed. Finally, CSC-CM-activated neutrophils endowed A375 cells with stemness traits, stimulating both sphere formation and ABCG2 expression. Conclusion: Collectively, our results suggest that melanoma SCs can prime neutrophils to support cancer progression.

Vitamin D3 Priming of Dendritic Cells Shifts Human Neutrophil-Dependent Th17 Cell Development to Regulatory T Cells

Vitamin D3 (VD3) is a potential adjuvant for use in tolerogenic vaccine formulations that target dendritic cells (DCs) for the treatment of chronic inflammatory disorders, e.g., autoimmune diseases. These disorders are often associated with enhanced activity of IL-17-producing T helper 17 (Th17) cells which develop in a DC-driven and neutrophil-dependent fashion. Here, we investigated the effect of VD3 on Candida albicans-specific human T-cell differentiation, since C. albicans is a model pathogen for Th17 cell development. VD3 priming of DCs restricted neutrophil-dependent Th17 cell development and neutrophil-independent Th1 cell formation from naive CD4⁺ T cells. In line with this, the production of Th1/Th17-polarizing cytokines IL-12 and IL-23 by DCs was reduced by VD3 priming. Development of both FoxP3⁺CD127_lowCD25⁺ Tregs and IL-10-producing T cells was significantly enhanced in VD3-primed conditions, even in the presence of neutrophils. ICOS⁺ Tregs, major IL-10 producers, CD69⁺FoxP3⁺, and TIGIT⁺FoxP3⁺ Tregs were significantly induced by VD3 priming as well. Our data support the potential use of VD3 as an adjuvant to induce tolerance in the treatment of autoimmune disorders, including those in which neutrophils are involved in pathogenesis, since we show that Treg development is enhanced by VD3 even in the presence of neutrophils, while Th17 cell development is restricted.

From infection to repair: Understanding the workings of our innate immune cells

In a world filled with microbes, some posing a threat to our body, our immune system is key to living a healthy life. The innate immune system is made of various cell types that act to guard our bodies. Unlike the adaptive immune system that has a specific response, our innate immune system encompasses cells that elicit unspecific immune responses, triggered whenever the right signals are detected. Our understanding of immunity started with the concept of our immune system only responding to "nonself" like the pathogens that invade our body. However, over the past few decades, we have learned that the immune system is more than an on/off switch that recognizes nonself. The innate immune system regularly patrols our bodies for pathogens and tissue damage. Our innate immune system not only seeks to resolve infection but also repair tissue injury, through phagocytosing debris and initiating the release of growth factors. Recently, we are starting to see that it is not just recognizing danger, our innate immune system plays a crucial role in repair. Innate immune cells phenotypically change during repair. In the context of severe injury or trauma, our innate immune system is modified quite drastically to help repair, resulting in reduced infection control. Moreover, these changes in immune cell function can be modified by sex as a biological variable. From past to present, in this overview, we provide a summary of the innate immune cells and pathways in infection and tissue repair. This article is categorized under: Immune System Diseases > Molecular and Cellular Physiology.

Integrative analysis of immune-related multi-omics profiles identifies distinct prognosis and tumor microenvironment patterns in osteosarcoma

Osteosarcoma (OS) is the most common primary malignancy of bone. Epigenetic regulation plays a pivotal role in cancer development in various aspects, including immune response. In this study, we studied the potential association of alterations in the DNA methylation and transcription of immune-related genes with changes in the tumor microenvironment (TME) and tumor prognosis of OS. We obtained multi-omics data for OS patients from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO) databases. By referring to curated immune signatures and using a consensus clustering method, we categorized patients based on immune-related DNA methylation patterns (IMPs), and evaluated prognosis and TME characteristics of the resulting patient subgroups. Subsequently, we used a machine-learning approach to construct an IMP-associated prognostic risk model incorporating the expression of a six-gene signature (MYC, COL13A1, UHRF2, MT1A, ACTB, and GBP1), which was then validated in an independent patient cohort. Furthermore, we evaluated TME patterns, transcriptional variation in biological pathways, somatic copy number alteration, anticancer drug sensitivity, and potential responsiveness to immune checkpoint inhibitor therapy with regard to our IMP-associated signature scoring model. By integrative IMP and transcriptomic analysis, we uncovered distinct prognosis and TME patterns in OS. Finally, we constructed a classifying model, which may aid in prognosis prediction and provide a potential rationale for targeted- and immune checkpoint inhibitor therapy in OS.

Neutrophils Contribute to Severity of Tuberculosis Pathology and Recovery From Lung Damage Pre- and Posttreatment

BACKGROUND

Despite microbiological cure, about 50% of tuberculosis (TB) patients have poor lung recovery. Neutrophils are associated with lung pathology; however, CD16/CD62L-defined subsets have not been studied in TB. Using flow cytometry, we monitored frequencies, phenotype, and function of neutrophils following stimulation with Mycobacterium tuberculosis (Mtb) whole cell lysate (WCL) and ESAT-6/CFP-10 fusion protein (EC) in relation to lung pathology.

METHODS

Fresh blood from 42 adult, human immunodeficiency virus (HIV)-negative TB patients were analyzed pre- and post-therapy, with disease severity determined using chest radiography and bacterial load. Flow cytometry was used to monitor frequencies, phenotype, and function (generation of reactive oxygen species [ROS], together with CD11b, tumor necrosis factor, and interleukin 10 [IL-10] expression) of neutrophils following 2-hour stimulation with Mtb-specific antigens.

RESULTS

Total neutrophils decreased by post-treatment compared to baseline (P = .0059); however, CD16brCD62Lbr (segmented) neutrophils increased (P = .0031) and CD16dimCD62Lbr (banded) neutrophils decreased (P = .038). Banded neutrophils were lower in patients with severe lung damage at baseline (P = .035). Following WCL stimulation, ROS from segmented neutrophils was higher in patients with low Mtb loads even after adjusting for sex (P = .038), whereas IL-10-expressing CD16dimCD62Llo cells were higher in patients with mild damage (P = .0397) at baseline.

CONCLUSIONS

High ROS generation, low levels of banded neutrophils, and high levels of IL-10-expressing CD16dimCD62Llo neutrophils are associated with reduced lung pathology at diagnosis. Hence, neutrophils are potential early indicators of TB severity and promising targets for TB host-directed therapy.

Periodontitis pathogen Porphyromonas gingivalis promotes pancreatic tumorigenesis via neutrophil elastase from tumor-associated neutrophils

Intratumor microbiome shapes the immune system and influences the outcome of various tumors. Porphyromonas gingivalis (P. gingivalis), the keystone periodontal pathogen, is highly epidemically connected with pancreatic cancer (PC). However, its causative role and the underlining mechanism in promoting PC oncogenesis remain unclear. Here, we illustrated the landscape of intratumor microbiome and its bacterial correlation with oral cavity in PC patients, where P. gingivalis presented both in the oral cavity and tumor tissues. When exposed to P. gingivalis, tumor development was accelerated in orthotopic and subcutaneous PC mouse model, and the cancerous pancreas exhibited a neutrophils-dominated proinflammatory tumor microenvironment. Mechanistically, the intratumoral P. gingivalis promoted PC progression via elevating the secretion of neutrophilic chemokines and neutrophil elastase (NE). Collectively, our study disclosed the bacterial link between periodontitis and PC, and revealed a previously unrecognized mechanism of P. gingivalis in PC pathophysiology, hinting at therapeutic implications.

Neutrophil infiltration combined with necrosis in the primary tumor is a useful prognostic indicator for three‑year disease‑free survival time in patients with colorectal cancer

Histopathological evaluation plays a key role in the diagnosis of colorectal cancer (CRC). Tumor-related local inflammation is regarded as a novel prognostic parameter. Neutrophils constitute one of the main types of inflammatory cells. The aim of the present study was to evaluate the prognostic value of intratumoral tumor-associated neutrophils (intraTANs), stromal TANs (stromaTANs) and necrosis, as well as their combined parametric value in formalin-fixed paraffin-embedded tissue sections from patients with CRC. For this purpose, a retrospective study of 160 patients with CRC who underwent surgery was conducted. The association of intraTANs, stromaTANs, necrosis and their combined parametric value with the clinicopathological features of patients with CRC was examined. The Kaplan-Meier method and the log-rank test were used to compare survival curves. To identify independent prognostic factors, uni- and multivariate Cox proportional hazards regression models were used. StromaTANs were associated with lymph node metastasis (P=0.049) and tumor deposits (P=0.041). In addition, necrosis was found to be associated with venous (P=0.003), lymphatic (P=0.007) and perineural (P=0.015) invasion, as well as with lymph node metastasis (P=0.033), the number of invaded lymph nodes (P=0.012), and lymph node pouch invasion (P=0.043). Furthermore, necrosis was found to be associated with the white blood cell count (P=0.030), neutrophil count (P=0.011), the combined neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (NLR-PLR) (P=0.038), and the combined platelet and NLR (PLT-NLR status) (P=0.030), as well as with the serum carcinoembryonic antigen (CEA) levels following surgery (P=0.011) and the monocyte-to-lymphocyte ratio (P=0.023). The combined parametric value was found to be associated with pT stage (P=0.049), venous (P=0.034) and lymphatic (P=0.026) invasion, and with serum CEA levels prior to surgery (P=0.029). The analysis of the 3-year disease-free survival (DFS) time revealed that tumor growth [hazard ratio (HR), 2.070; 95% CI, 1.837-3.808; P=0.003] and the combined parametric value (intraTANs, stromaTANs and necrosis, HR, 1.577; 95% CI, 1.372-3.032; P=0.028) were independent factors for patients with CRC. Taken together, the findings of the present study demonstrated that the combined value of neutrophils and necrosis examined in the cancerous tissue may be used as a prognostic factor for the 3-year DFS time in patients with CRC.

Blocking TGF-β Expression Attenuates Tumor Growth in Lung Cancers, Potentially Mediated by Skewing Development of Neutrophils

In the tumor microenvironment (TME), cells secrete a cytokine known as transforming growth factor-β (TGF-β), which polarizes tumor-associated neutrophils (TANs) towards a protumor phenotype. In this work, C57BL/6 mice with TGF-β1 gene knocked out selectively in myofibroblasts receive orthotopic implantation of Lewis lung carcinoma (LLC). Then, TANs' differentiation and tumor growth are studied both in vivo and in vitro, to examine the potential effects of TGF-β levels in TME on neutrophil polarization and cancer progression. Possible results are anticipated and discussed from various aspects. Though tumor suppression via inhibition of TGF-β signaling has been widely studied in this field, this study is the first to present a detailed experimental design for evaluating the potential antitumor effects of blocking TGF-β expression. This work provides a creative approach for cancer treatment targeting specific cytokines, and the experimental design presented here may apply to future research on other cytokines, promoting the development of novel cancer-treating strategies.

The Pathogenesis of Ischemia-Reperfusion Induced Acute Kidney Injury Depends on Renal Neutrophil Recruitment Whereas Sepsis-Induced AKI Does Not

Acute kidney injury (AKI) may be induced by different causes, including renal ischemia-reperfusion injury and sepsis, which represent the most common reasons for AKI in hospitalized patients. AKI is defined by reduced urine production and/or increased plasma creatinine. However, this definition does not address the molecular mechanisms of different AKI entities, and uncertainties remain regarding distinct pathophysiological events causing kidney injury in the first place. In particular, sepsis-induced AKI is considered not to be associated with leukocyte infiltration into the kidney, but a direct investigation of this process is missing to this date. In this study, we used two murine AKI models induced by either renal ischemia-reperfusion injury (IRI) or cecal ligation and puncture (CLP) to investigate the contribution of neutrophils to tissue injury and kidney function. By using VEC-Y731F mice, in which neutrophil recruitment is impaired, we analyzed the specific contribution of neutrophil recruitment to the pathogenesis of IRI- and CLP-induced AKI. We observed that the degree of renal injury evaluated by plasma creatinine, urinary biomarkers and histological analyses, following IRI-induction was dependent on neutrophil migration into the kidney, whereas the pathogenesis of CLP-induced AKI was independent of neutrophil recruitment. Furthermore, plasma transfer experiments suggest that the pathogenesis of CLP-induced AKI relies on circulating inflammatory mediators. These results extend our knowledge of the AKI pathogenesis and may help in the development of prophylactic and therapeutic treatments for AKI patients.

Multisystem Inflammatory Syndrome and Autoimmune Diseases Following COVID-19: Molecular Mechanisms and Therapeutic Opportunities

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), has led to huge concern worldwide. Some SARS-CoV-2 infected patients may experience post–COVID-19 complications such as multisystem inflammatory syndrome, defined by symptoms including fever and elevated inflammatory markers (such as elevation of C reactive protein (CRP), erythrocyte sedimentation rate, fibrinogen, procalcitonin test, D-dimer, ferritin, lactate dehydrogenase or IL-6, presence of neutrophilia, lymphopenia, decreased albumin, and multiple organ dysfunction). Post–COVID-19 complications may also manifest as autoimmune diseases such as Guillain-Barré syndrome and systemic lupus erythematosus. Signaling disorders, increased inflammatory cytokines secretion, corticosteroid use to treat COVID-19 patients, or impaired immune responses are suggested causes of autoimmune diseases in these patients. In this review, we discuss the molecular and pathophysiological mechanisms and therapeutic opportunities for multisystem inflammatory syndrome and autoimmune diseases following SARS-CoV-2 infection with the aim to provide a clear view for health care providers and researchers.

Clinical Translation of Neutrophil Imaging and Its Role in Cancer

Neutrophils are the first line of defense against pathogens and abnormal cells. They regulate many biological processes such as infections and inflammation. Increasing evidence demonstrated a role for neutrophils in cancer, where different subpopulations have been found to possess both pro- or anti-tumorigenic functions in the tumor microenvironment. In this review, we discuss the phenotypic and functional diversity of neutrophils in cancer, their prognostic significance, and therapeutic relevance in human and preclinical models. Molecular imaging methods are increasingly used to probe neutrophil biology in vivo, as well as the cellular changes that occur during tumor progression and over the course of treatment. This review will discuss the role of neutrophil imaging in oncology and the lessons that can be drawn from imaging in infectious diseases and inflammatory disorders. The major factors to be considered when developing imaging techniques and biomarkers for neutrophils in cancer are reviewed. Finally, the potential clinical applications and the limitations of each method are discussed, as well as the challenges for future clinical translation.