Neutrophil peptide 1 accelerates the clearance of degenerative axons during Wallerian degeneration by activating macrophages after peripheral nerve crush injury

Macrophages play an important role in peripheral nerve regeneration,but the specific mechanism of regeneration is still unclear.Our preliminary findings indicated that neutrophil peptide 1 is an innate immune peptide closely involved in peripheral nerve regeneration.However,the mechanism by which neutrophil peptide 1 enhances nerve regeneration remains unclear.This study was designed to investigate the relationship between neutrophil peptide 1 and macrophages in vivo and in vitro in peripheral nerve crush injury.The functions of RAW 264.7 cells we re elucidated by Cell Counting Kit-8 assay,flow cytometry,migration assays,phagocytosis assays,immunohistochemistry and enzyme-linked immunosorbent assay.Axonal debris phagocytosis was observed using the CUBIC(Clear,Unobstructed Brain/Body Imaging Cocktails and Computational analysis)optical clearing technique during Wallerian degeneration.Macrophage inflammatory factor expression in different polarization states was detected using a protein chip.The results showed that neutrophil peptide 1 promoted the prolife ration,migration and phagocytosis of macrophages,and CD206 expression on the surfa ce of macrophages,indicating M2 polarization.The axonal debris clearance rate during Wallerian degeneration was enhanced after neutrophil peptide 1 intervention.Neutrophil peptide 1 also downregulated inflammatory factors interleukin-1α,-6,-12,and tumor necrosis factor-αin invo and in vitro.Thus,the results suggest that neutrophil peptide 1 activates macrophages and accelerates Wallerian degeneration,which may be one mechanism by which neutrophil peptide 1 enhances peripheral nerve regeneration.

The neutrophil–osteogenic cell axis promotes bone destruction in periodontitis

The immune-stromal cell interactions play a key role in health and diseases. In periodontitis, the most prevalent infectious disease in humans, immune cells accumulate in the oral mucosa and promote bone destruction by inducing receptor activator of nuclear factor-κB ligand (RANKL) expression in osteogenic cells such as osteoblasts and periodontal ligament cells. However, the detailed mechanism underlying immune–bone cell interactions in periodontitis is not fully understood. Here, we performed single-cell RNAsequencing analysis on mouse periodontal lesions and showed that neutrophil–osteogenic cell crosstalk is involved in periodontitis-induced bone loss. The periodontal lesions displayed marked infiltration of neutrophils, and in silico analyses suggested that the neutrophils interacted with osteogenic cells through cytokine production. Among the cytokines expressed in the periodontal neutrophils, oncostatin M (OSM) potently induced RANKL expression in the primary osteoblasts, and deletion of the OSM receptor in osteogenic cells significantly ameliorated periodontitis-induced bone loss. Epigenomic data analyses identified the OSM-regulated RANKL enhancer region in osteogenic cells, and mice lacking this enhancer showed decreased periodontal bone loss while maintaining physiological bone metabolism. These findings shed light on the role of neutrophils in bone regulation during bacterial infection, highlighting the novel mechanism underlying osteoimmune crosstalk.

Neutrophil extracellular traps mediate neuro-immunothrombosis

Neutrophil extracellular traps are primarily composed of DNA and histones and are released by neutrophils to promote inflammation and thrombosis when stimulated by various inflammato ry reactions.Neutrophil extracellular trap formation occurs through lytic and non-lytic pathways that can be further classified by formation mechanisms.Histones,von Willebrand factor,fibrin,and many other factors participate in the interplay between inflammation and thrombosis.Neuroimmunothrombosis summarizes the intricate interplay between inflammation and thrombosis during neural development and the pathogenesis of neurological diseases,providing cutting-edge insights into post-neurotrauma thrombotic events.The blood-brain barrier defends the brain and spinal cord against external assaults,and neutrophil extracellular trap involvement in blood-brain barrier disruption and immunothrombosis contributes substantially to secondary injuries in neurological diseases.Further research is needed to understand how neutrophil extracellular traps promote blood-brain barrier disruption and immunothrombosis,but recent studies have demonstrated that neutrophil extracellular traps play a crucial role in immunothrombosis,and identified modulators of neuro-immunothrombosis.However,these neurological diseases occur in blood vessels,and the mechanisms are unclear by which neutrophil extracellular traps penetrate the blood-brain barrier to participate in immunothrombosis in traumatic brain injury.This review discusses the role of neutrophil extracellular traps in neuro-immunothrombosis and explores potential therapeutic interventions to modulate neutrophil extracellular traps that may reduce immunothrombosis and improve traumatic brain injury outcomes.

Cancer-educated neutrophils promote lung cancer progression via PARP-1-ALOX5-mediated MMP-9 expression

Objective:Neutrophils are one of the most predominant infiltrating leukocytes in lung cancer tissues and are associated with lung cancer progression.How neutrophils promote lung cancer progression,however,has not been established.Methods:Kaplan–Meier plotter online analysis and tissue immunohistochemistry were used to determine the relationship between neutrophils and overall survival in lung cancer patients.The effect of neutrophils on lung cancer was determined using the Transwell migration assay,a proliferation assay,and a murine tumor model.Gene knockdown was used to determine poly ADPribose polymerase(PARP)-1 function in lung cancer-educated neutrophils.Western blot analysis and gelatin zymography were used to demonstrate the correlation between PARP-1 and matrix metallopeptidase 9(MMP-9).Immunoprecipitation coupled to mass spectrometry(IP/MS)was used to identify the proteins interacting with PARP-1.Co-immunoprecipitation(Co-IP)was used to confirm that PARP-1 interacts with arachidonate 5-lipooxygenase(ALOX5).Neutrophil PARP-1 blockage by AG14361 rescued neutrophil-promoted lung cancer progression.Results:An increased number of infiltrating neutrophils was negatively associated with overall survival in lung cancer patients(P<0.001).Neutrophil activation promoted lung cancer cell invasion,migration,and proliferation in vitro,and murine lung cancer growth in vivo.Mechanistically,PARP-1 was shown to be involved in lung cancer cell-induced neutrophil activation to increase MMP-9 expression through interacting and stabilizing ALOX5 by post-translational protein modification(PARylation).Blocking PARP-1 by gene knockdown or AG14361 significantly decreased ALOX5 expression and MMP-9 production,and eliminated neutrophil-mediated lung cancer cell invasion and in vivo tumor growth.Conclusion:We identified a novel mechanism by which PARP-1 mediates lung cancer cell-induced neutrophil activation and PARylates ALOX5 to regulate MMP-9 expression,which exacerbates lung cancer progression.

The Combined Effect of Lumenato and Ceramide in the Protection of Collagen Damage Induced by Neutrophils in Normal Human Dermal Fibroblasts

Introduction: Collagen is the primary structural protein fibroblasts produce in the skin’s extracellular matrix. Infiltration of neutrophils into the epidermis and dermis by exposure to UV causes collagen damage and contributes to photoaging. Methods: To study the combined effect of Lumenato and ceramide in preventing collagen-1 damage induced by phagocytes, we used co-cultures of normal human dermal fibroblasts (fibroblasts) and activated human neutrophils. The present study aimed to determine the protective effect of the combination of Lumenato and ceramide on fibroblast collagen-1 damage induced by neutrophils. Results: Lumenato (in the range of 6.5 - 208 μg/ml) or ceramide (in the range of 0.1 - 50 μM) inhibited the production of superoxides and MPO by TNFα-stimulated neutrophils, as well as the production of NO by LPS-stimulated macrophages in a dose-dependent manner. The combinations of Lumenato and ceramide, in low concentrations, caused synergistic prevention of fibroblasts’ collagen-1 damage induced by TNFα-activated neutrophils, detected by fluorescence immunostaining and WB analysis. MPO activity in the supernatants of the co-cultures was also synergistically inhibited. Adding Lumenato or ceramide singly or in combinations in these low concentrations to the fibroblast cultures did not affect the expression of collagen-1. The combinations of Lumenato or ceramide in these concentrations also caused a synergistic inhibition of NO production by activated macrophages. Conclusions: The results suggest that combining low concentrations of Lumenato and ceramide results in synergistic protection against fibroblasts’ collagen-1 damage induced by neutrophils, thus indicating their possible potential for enhanced skin health.

Overcoming neutrophil-induced immunosuppression in postoperative cancer therapy: Combined sialic acid-modified liposomes with scaffold-based vaccines

Immunotherapy is a promising approach for preventing postoperative tumor recurrence and metastasis. However, inflammatory neutrophils, recruited to the postoperative tumor site, have been shown to exacerbate tumor regeneration and limit the efficacy of cancer vaccines. Consequently, addressing postoperative immunosuppression caused by neutrophils is crucial for improving treatment outcomes. This study presents a combined chemoimmunotherapeutic strategy that employs a biocompatible macroporous scaffold-based cancer vaccine (S-CV) and a sialic acid (SA)-modified, doxorubicin (DOX)-loaded liposomal platform (DOX@SAL). The S-CV contains whole tumor lysates as antigens and imiquimod (R837, Toll-like receptor 7 activator)-loaded PLGA nanoparticles as immune adjuvants for cancer, which enhance dendritic cell activation and cytotoxic T cell proliferation upon localized implantation. When administered intravenously, DOX@SAL specifically targets and delivers drugs to activated neutrophils in vivo, mitigating neutrophil infiltration and suppressing postoperative inflammatory responses. In vivo and vitro experiments have demonstrated that S-CV plus DOX@SAL, a combined chemo-immunotherapeutic strategy, has a remarkable potential to inhibit postoperative local tumor recurrence and distant tumor progression, with minimal systemic toxicity, providing a new concept for postoperative treatment of tumors.

Crossroads:Pathogenic role and therapeutic targets of neutrophil extracellular traps in rheumatoid arthritis

Rheumatoid arthritis(RA)is a prevalent autoimmune disease whose main features include chronic synovial inflammation,bone destruction,and joint degeneration.Neutrophils are often considered to be the first responders to inflammation and are a key presence in the inflammatory milieu of RA.Neutrophil extracellular traps(NETs),a meshwork of DNA-histone complexes and proteins released by activated neutrophils,are widely involved in the pathophysiology of autoimmune diseases,especially RA,in addition to playing a key role in the neutrophil innate immune response.NETs have been found to be an important source of citrullinated autoantigen antibodies and inflammatory factor release,which can activate RA synovial fibroblasts(FLS)and cause joint damage.This article reviews the role of NETs in the pathophysiology of RA,demonstrating the application of multiple molecules with various therapies,with a view to informing the discovery and development of novel biomarkers and therapeutic targets for RA.

Prognostic value of circulating tumor cells combined with neutrophil-lymphocyte ratio in patients with hepatocellular carcinoma

BACKGROUND Circulating tumor cell(CTC)count and neutrophil-to-lymphocyte ratio(NLR)are both closely associated with the prognosis of hepatocellular carcinoma(HCC).AIM To investigate the prognostic value of combining these two indicators in HCC.METHODS Clinical data were collected from patients with advanced HCC who received im-mune therapy combined with targeted therapy at the Department of Oncology,the Affiliated Hospital of Southwest Medical University,Sichuan,China,from 2021 to 2023.The optimal cutoff values for CTC programmed death-ligand 1(PD-L1)(+)>1 or CTC PD-L1(+)≤1 and NLR>3.89 or NLR≤3.89 were evaluated using X-Tile software.Patients were categorized into three groups based on CTC PD-L1(+)counts and NLR:CTC-NLR(0),CTC-NLR(1),and CTC-NLR(2).The relationship between CTC-NLR and clinical variables as well as survival rates was assessed.RESULTS Patients with high CTC PD-L1(+)expression or NLR at baseline had shorter median progression-free survival(m-PFS)and median overall survival(mOS)than those with low levels of CTC PD-L1(+)or NLR(P<0.001).Mean-while,patients in the CTC-NLR(2)group showed a significant decrease in mPFS and mOS.Cox regression analysis revealed that alpha-fetoprotein(AFP),CTC PD-L1(+),and CTC-NLR were independent predictors of OS.The time-dependent receiver operating characteristic curve showed that the area under the curve of CTC-NLR at 12 months(0.821)and 18 months(0.821)was superior to that of AFP and CTC PD-L1(+).CONCLUSION HCC patients with high CTC PD-L1(+)or NLR expression tend to exhibit poor prognosis,and a high baseline CTC-NLR score may indicate low survival.CTC-NLR may serve as an effective prognostic indicator for patients with advanced HCC receiving immunotherapy combined with targeted therapy.

FOXO1 reshapes neutrophils to aggravate acute brain damage and promote late depression after traumatic brain injury

Background:Neutrophils are traditionally viewed as first responders but have a short onset of action in response to traumatic brain injury(TBI).However,the heterogeneity,multifunctionality,and time-dependent modulation of brain damage and outcome mediated by neutrophils after TBI remain poorly understood.Methods:Using the combined single-cell transcriptomics,metabolomics,and proteomics analysis from TBI patients and the TBI mouse model,we investigate a novel neutrophil phenotype and its associated effects on TBI outcome by neurological deficit scoring and behavioral tests.We also characterized the underlying mechanisms both invitro and invivo through molecular simulations,signaling detections,gene expression regulation assessments[including dual-luciferase reporter and chromatin immunoprecipitation(ChIP)assays],primary cultures or co-cultures of neutrophils and oligodendrocytes,intracellular iron,and lipid hydroperoxide concentration measurements,as well as forkhead box protein O1(FOXO1)conditional knockout mice.Results:We identified that high expression of the FOXO1 protein was induced in neutrophils after TBI both in TBI patients and the TBI mouse model.Infiltration of these FOXO1high neutrophils in the brain was detected not only in the acute phase but also in the chronic phase post-TBI,aggravating acute brain inflammatory damage and promoting late TBI-induced depression.In the acute stage,FOXO1 upregulated cytoplasmic Versican(VCAN)to interact with the apoptosis regulator B-cell lymphoma-2(BCL-2)-associated X protein(BAX),suppressing the mitochondrial translocation of BAX,which mediated the antiapoptotic effect companied with enhancing interleukin-6(IL-6)production of FOXO1high neutrophils.In the chronic stage,the“FOXO1-transferrin receptor(TFRC)”mechanism contributes to FOXO1high neutrophil ferroptosis,disturbing the iron homeostasis of oligodendrocytes and inducing a reduction in myelin basic protein,which contributes to the progression of late depression after TBI.Conclusions:FOXO1high neutrophils represent a novel neutrophil phenotype that emerges in response to acute and chronic TBI,which provides insight into the heterogeneity,reprogramming activity,and versatility of neutrophils in TBI.

Machine learning based on metabolomics unveils neutrophil extracellular trap-related metabolic signatures in non-small cell lung cancer patients undergoing chemoimmunotherapy

BACKGROUND Non-small cell lung cancer(NSCLC)is the primary form of lung cancer,and the combination of chemotherapy with immunotherapy offers promising treatment options for patients suffering from this disease.However,the emergence of drug resistance significantly limits the effectiveness of these therapeutic strategies.Consequently,it is imperative to devise methods for accurately detecting and evaluating the efficacy of these treatments.AIM To identify the metabolic signatures associated with neutrophil extracellular traps(NETs)and chemoimmunotherapy efficacy in NSCLC patients.METHODS In total,159 NSCLC patients undergoing first-line chemoimmunotherapy were enrolled.We first investigated the characteristics influencing clinical efficacy.Circulating levels of NETs and cytokines were measured by commercial kits.Liquid chromatography tandem mass spectrometry quantified plasma metabolites,and differential metabolites were identified.Least absolute shrinkage and selection operator,support vector machine-recursive feature elimination,and random forest algorithms were employed.By using plasma metabolic profiles and machine learning algorithms,predictive metabolic signatures were established.RESULTS First,the levels of circulating interleukin-8,neutrophil-to-lymphocyte ratio,and NETs were closely related to poor efficacy of first-line chemoimmunotherapy.Patients were classed into a low NET group or a high NET group.A total of 54 differential plasma metabolites were identified.These metabolites were primarily involved in arachidonic acid and purine metabolism.Three key metabolites were identified as crucial variables,including 8,9-epoxyeicosatrienoic acid,L-malate,and bis(monoacylglycerol)phosphate(18:1/16:0).Using metabolomic sequencing data and machine learning methods,key metabolic signatures were screened to predict NET level as well as chemoimmunotherapy efficacy.CONCLUSION The identified metabolic signatures may effectively distinguish NET levels and predict clinical benefit from chemoimmunotherapy in NSCLC patients.

Phagocytosis: A Practical Approach for Evaluating Neutrophil Function in Health and Disease

Neutrophils, crucial players in the effector phase of the immune response, are recognized as important mediators of both innate and adaptive immune responses. Through the production of pro- and anti-inflammatory cytokines, they modulate the function of T and other lymphoid cells. Countless reports have highlighted the importance of these cells as efficient antimicrobial agents and annotated their involvement in the pathology of infectious and noninfectious diseases. The development of modern, sophisticated technologies has allowed the study of the functions of these cells in clinical settings. These advanced technologies include fluorescence-activated cell sorters, confocal microscopy, automated cell image analyzers, and live cell analysis instruments. Unfortunately, the cost of these modern instruments, maintenance, reagents, and the need for qualified technicians prohibit their use in low-income laboratories and universities in developing countries. With this in mind, we propose a series of basic tests that can be used in low-input clinical laboratories and universities to evaluate the function of neutrophils in health and disease. Our methodology allows us to assess in a practical and low-cost manner the functions of neutrophils in the phagocytic process, including opsonization, ingestion, ROI production (NBT reduction), myeloperoxidase content, phagosome-lysosome fusion, microbicidal activity, and NET production. Thus, under a disadvantageous ambiance, this may guide physicians in deciding whether a patient’s illness involves phagocytic defects without imposing a heavy financial burden.Graphical Abstract[-rId13-]

Correlation of neutrophil to lymphocyte ratio to severity of coronary artery disease and in-hospital clinical outcomes in patients with acute coronary syndrome: A prospective observational study

Objective:To explore correlation of neutrophil-to-lymphocyte ratio(NLR)to severity of coronary artery disease(CAD)and in-hospital clinical outcomes in patients with acute coronary syndrome(ACS).Methods:In this prospective and observational study,we recruited 500 patients with ACS.For all the eligible patients,demographic details were collected,and laboratory parameters were evaluated.The CAD severity was evaluated in terms of the number of involved vessels.The NLR was calculated based on neutrophils and lymphocytes and the correlation of various risk factors and severity and outcome of CAD was performed.Results:77.2%of Patients was male,and 52%of the patients aged between 55-70 years.Based on the type of ACS,396 out of 500 patients had ST-elevation myocardial infarction.An ascending trend in the white blood cell levels and NLR value was noted as the severity of the ACS increased and the highest white blood cell levels and NLR was noted among classⅣpatients.The mean NLR value among the non-survivors were higher compared to the survivors(9.52±5.72 vs.4.76±2.36;P<0.01).Receiver operating curve showed that the cut-off NLR value was 5.76 with a sensitivity of 75.0%and a specificity of 77.3%.Conclusions:The NLR can be used as an independent prognostic marker in ACS.An elevated NLR value serves as a reliable predictor for short-term complications,notably in-hospital mortality.

Correlation between Neutrophil Percentage-to-albumin Ratio and Coronary Heart Disease Complicated with Diabetes Mellitus

[Objectives]This study was conducted to explore the relationship between neutrophil percentage-to-albumin ratio(NPAR)and coronary heart disease complicated with diabetes.[Methods]A total of 603 patients with coronary heart disease who underwent coronary angiography in Pingquan County Hospital from January,2023 to December,2023 and met the inclusion criteria were included as the research object.All the patients were divided into a coronary heart disease complicated with diabetes group(CAD+T2DM group)(n=298 cases)and a control group(CAD group)(n=305 cases),according to patients medical history,heart color ultrasound and biochemical test results.The clinical data,biochemical test results and coronary artery imaging data of patients were recorded,and the Gensini score was calculated.The neutrophil percentage(NEUT%)and albumin count were determined to calculate NPAR.[Results]The NPAR value of the coronary heart disease complicated with diabetes mellitus group was(1.6±0.42),which was significantly higher than that of the control group(1.47±0.49),and the difference was statistically significant(P<0.05).The area under the ROC curve was 0.619(95%CI:0.591-0.675,P<0.05),and the prediction of coronary heart disease complicated with diabetes using NPAR showed a Youden index of 0.31,a sensitivity of 60.4%,a specificity of 40.3%,and a best cut-off score of 1.4506.[Conclusions]The neutrophil percentage-to-albumin ratio(NPAR)is closely related to coronary heart disease complicated with diabetes mellitus,and NPAR has clinical application value in the diagnosis of coronary heart disease complicated with diabetes mellitus.

Predictive Value of the Neutrophil to Lymphocyte Ratio (NLR) to Predict the Development of Preeclampsia and Pregnancy Induced Hypertension at 1st Trimester

Introduction: Hypertensive disorder in pregnancy affects 4 to 6 percent of all pregnancies and carries risks for the both baby and the mother. Only a few groups of women who are at high-risk pregnancies are received prophylaxis Aspirin, more than 15 percent of women develop pre-eclampsia with a single minor risk factor. Methods: This descriptive cross-sectional study was conducted to compare the 1st trimester NLR value of normotensive, pregnancy induced hypertensive and pre-eclamptic pregnant women. The study was conducted with a sample of 416, antenatal patients who were admitted to ward 25, at Colombo North Teaching Hospital Ragama. Data was collected as separated three groups. NLR value was calculated separately and ANOVA test was used to analyze the 3 categorical data. Post HOC test was done to assess the multiple comparison. Results: The prevalence rates of pregnancy induced hypertension and pre-eclampsia among the pregnant women were 8.6% and 5.7%. The mean NLR values of normotensive group was 2.708, pregnancy induced hypertensive group was 2.650 and pre eclamptic group was 3.789. There was a significant difference in NLR value between pre eclamptic group and other two groups with P value of Conclusion: The 1st trimester NLR value of pre eclamptic patients significantly increased compared to normotensive women.

Systemic Immune-Inflammation Index (SII) and Neutrophil-Lymphocyte Ratio (NLR) as Systemic Inflammatory Predictors in the Diagnosis of Bullous Pemphigoid and Pemphigus Vulgaris

Introduction: Autoimmune blistering skin disorders such as Bullous Pemphigoid and Pemphigus Vulgaris present diagnostic challenges. The Systemic Immune-Inflammation Index (SII) and Neutrophil-Lymphocyte Ratio (NLR), are inflammatory markers used to assess the body’s immune-inflammatory response. Objectives: The study aims to evaluate the significance of hematologic markers, specifically the Systemic Immune-Inflammation Index (SII) and Neutrophil-Lymphocyte Ratio (NLR), as diagnostic predictors of bullous pemphigoid (BP) and pemphigus vulgaris (PV). Methods: A retrospective study of 64 patients (36 with BP and 28 with PV). Patient clinical data: age, gender, complete blood count, autoimmune antibody levels (Dsg1, 3 and BP180, 230), IgE and C-reactive protein, and history of hypertension, diabetes, brain infarction, and coronary heart disease. The data was analyzed using SPSS. Results: The study involved 36 (56.3%) diagnosed with bullous pemphigoid (BP) and 28 (43.75%) with pemphigus vulgaris (PV). The average age in BP was 71 ± 8 and 52 ± 13 in PV. Laboratory findings showed high levels of Dsg1, Dsg3, neutrophil count, and lymphocyte count in PV, while high levels of eosinophils with a significant increase in C-reactive protein (CRP) in BP. Blood biomarkers, including NLR, PLR, SII, MPV, CRP, and IgE, proved an overall of 84.4% in disease prediction. Dsg1, Dsg3, BP180, and BP230 showed an overall of 88.1%. No significant relationship was noted between NLR, SII, and patients with comorbidities. Conclusion: The study highlights the diagnostic potential of SII and NLR in addition to hematologic markers in BP and PV, emphasizing their role in early diagnosis and therapeutic interventions, requiring further validation in larger patient cohorts.

Neutrophil elastase:From mechanisms to therapeutic potential

Neutrophil elastase(NE),a major protease in the primary granules of neutrophils,is involved in microbicidal activity.NE is an important factor promoting inflammation,has bactericidal effects,and shortens the inflammatory process.NE also regulates tumor growth by promoting metastasis and tumor microenvironment remodeling.However,NE plays a role in killing tumors under certain conditions and promotes other diseases such as pulmonary ventilation dysfunction.Additionally,it plays a complex role in various physiological processes and mediates several diseases.Sivelestat,a specific NE inhibitor,has strong potential for clinical application,particularly in the treatment of coronavirus disease 2019(COVID-19).This review discusses the pathophysiological processes associated with NE and the potential clinical applications of sivelestat.

Neutrophils as key regulators of tumor immunity that restrict immune checkpoint blockade in liver cancer

Objective:Liver cancer is a deadly malignancy associated with high mortality and morbidity.Less than 20%of patients with advanced liver cancer respond to a single anti-PD-1 treatment.The high heterogeneity of neutrophils in the tumor immune microenvironment in liver cancer may contribute to resistance to immune checkpoint blockade(ICB).However,the underlying mechanism remains largely unknown.Methods:We established an orthotopic liver cancer model by using transposable elements to integrate the oncogenes Myc and KrasG12Dinto the genome in liver cells from conditional Trp53 null/null mice(pTMK/Trp53^(-/-)).Flow cytometry and immunohistochemistry were used to assess the changes in immune cells in the tumor microenvironment.An ex vivo coculture assay was performed to test the inhibitory effects of tumor-associated neutrophils(TANs)on CD8^(+)T cells.The roles of neutrophils,T cells,and NK cells were validated through antibody-mediated depletion.The efficacy of the combination of neutrophil depletion and ICB was evaluated.Results:Orthotropic pTMK/Trp53^(-/-)mouse liver tumors displayed a moderate response to anti-Ly6G treatment but not PD-1 blockade.Depletion of neutrophils increased the infiltration of CD8^(+)T cells and decreased the number of exhausted T cells in the tumor microenvironment.Furthermore,depletion of either CD8^(+)T or NK cells abrogated the antitumor efficacy of anti-Ly6G treatment.Moreover,the combination of anti-Ly6G with anti-PD-L1 enhanced the infiltration of cytotoxic CD8^(+)T cells and thereafter resulted in a significantly greater decrease in tumor burden.Conclusions:Our data suggest that TANs may contribute to the resistance of liver cancer to ICB,and combining TAN depletion with T cell immunotherapy synergistically increases antitumor efficacy.

Neutrophil-derived interleukin-17A participates in neuroinflammation induced by traumatic brain injury

After brain injury, infiltration and abnormal activation of neutrophils damages brain tissue and worsens inflammation, but the mediators that connect activated neutrophils with neuroinflammation have not yet been fully clarified. To identify regulators of neutrophil-mediated neuroinflammation after traumatic brain injury, a mouse model of traumatic brain injury was established by controlled cortical impact. At 7 days post-injury(sub-acute phase), genome-wide transcriptomic data showed that interleukin 17 A-associated signaling pathways were markedly upregulated, suggesting that interleukin 17 A may be involved in neuroinflammation. Double immunofluorescence staining showed that interleukin 17 A was largely secreted by neutrophils rather than by glial cells and neurons. Furthermore, nuclear factor-kappaB and Stat3, both of which are important effectors in interleukin 17 A-mediated proinflammatory responses, were significantly activated. Collectively, our findings suggest that neutrophil-derived interleukin 17 A participates in neutrophil-mediated neuroinflammation during the subacute phase of traumatic brain injury. Therefore, interleukin 17 A may be a promising therapeutic target for traumatic brain injury.

Hsa_circ_0036740 in familial adenomatous polyposis:Immune regulation and neutrophil effects in CRC based on highthroughput assay

Familial adenomatous polyposis(FAP)is an autosomal dominant disease with a high probability of becoming cancerous.Many RNAs potentially associated with FAP have not been identified.In this study,a circRNA(circular RNA)expression profile of FAP was established using a circRNA microarray,and differentially expressed circRNAs were verified by RT-qPCR.The effects of hsa_circ_0036740 on the malignant behavior of tumor cells(proliferation,apoptosis,and epithelial mesenchymal transition)and the levels of C3A complement protein expression were evaluated.Moreover,neutrophils were isolated and co-cultured with colorectal cancer cells(CRCs),followed by measurements of MPO-DNA,citrullinated histone H3,interleukin(IL)-1β,IL-6,and IL-8 levels.Nuclear translocation of arginine deiminase 4(PAD4)was observed using immunofluorescence assays.Based on the high-throughput assay,238 downregulated circRNAs,and 38 upregulated circRNAs were identified.A Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggested that immune regulation might be involved in FAP.A total of 10 DECs(differentially expressed circular RNAs)were identified by RT-qPCR,and among them,hsa_circ_0036740 showed the highest fold-change in upregulation.Results of gain-of-and loss-of-function studies revealed that hsa_circ_0036740 enhanced the malignant behavior of tumor cells,such as metastasis,proliferation,and apoptosis,with an increasing level of C3A complement.Moreover,hsa_circ_0036740 also significantly increased neutrophil extracellular trap formation and inflammation in neutrophils,as shown by an increased expression of PAD4.In conclusion,this study revealed the expression profiles of circRNAs in FAP and confirmed the possible involvement of hsa_circ_0036740 in the immune regulation mediated by neutrophils.Finally,hsa_circ_0036740 was suggested as a new therapeutic target for CRC.

Oral polymorphonuclear neutrophil characteristics in relation to oral health： a cross-sectional, observational clinical study

Polymorphonuclear neutmphils （PMNs） have a major role in the innate immune system. However, little is known about PMN contribution in relation to oral health. The objective of this study was to investigate the numbers and functional characteristics of oral PMNs （oPMNs） compared with circulatory PMNs （cPMNs）. Oral rinse and venous blood samples were obtained from 268 systemically and orally healthy volunteers in a cross-sectional observational study. PMN counts, cell cycle analysis and cellular activation state were investigated. Also, reactive oxygen species （ROS） production was analyzed, with and without bacterial stimulation （Fusobacterium nucleatum）. In males, 1.2 × 10^6- 1.0 ×10^6 oPMNs were collected, and showed a tendency to correlate with the levels of gingival bleeding （r= 0.215, P= 0.008）. Comparable oPMNs counts were found among females （1.0 ×10^6＋ 0.7 × 10^6）. More late-stage apoptotic/necrotic cells were found among the oPMNs （53.1%） compared with the cPMNs （8.5%; P〈 0.001）. Without additional stimulation, oPMNs were more activated than cPMNs, as indicated by higher expression of CD11b, CD63 and CD66b, and higher constitutive ROS levels （P〈 0.001）. Notably, in response to bacterial stimulation, oPMNs released comparable ROS levels as cPMNs （P= 0.042）. In conclusion, this study provides data on viable oPMNs showing high levels of activation in orally and systemically healthy individuals, free of apparent caries lesions and periodontal disease. These data suggests that although the oPMNs are in a more mature stage of their life cycle compared with the cPMNs, oPMNs are still responsive to stimulation, which indicates their functional potential and possible contribution to a healthy oral ecosystem.