The Neutrophil

Inwardly rectifying potassium channels regulate membrane potential polarization and direction sensing during neutrophil chemotaxis

Potassium channels regulate membrane potential and diverse physiological processes, including cell migration. However, the specific function of the inwardly rectifying potassium channels in immune cell chemotaxis is unknown. Here, we identified that the inwardly rectifying potassium channel Kir7.1 (KCNJ13) maintains the resting membrane potential and is required for directional sensing during neutrophil chemotaxis. Pharmacological or genetic inhibition of Kir7.1 in neutrophils impaired direction sensing toward various chemoattractants without affecting cell polarization in multiple neutrophil models. Using genetically encoded voltage indicators, we observed oscillating depolarization of the membrane potential in protrusions in zebrafish neutrophils, and Kir7.1 is required for polarized depolarization towards the chemokine source. Focal depolarization with optogenetic tools biases pseudopod selection and induces de novo protrusions. Global hyperpolarizing neutrophils stalled cell migration. Furthermore, Kir7.1 regulates GPCR signaling activation. This work adds membrane potential to the intricate feedforward mechanism, coupling the adaptive and excitable network required to steer immune cells in complex tissue environments.

Material-Mediated Immunotherapy to Regulate Bone Aging and Promote Bone Repair

As the global population ages, an increasing number of elderly people are experiencing weakened bone regenerative capabilities, resulting in slower bone repair processes and associated risks of various complications. This review outlines the research progress on biomaterials that promote bone repair through immunotherapy. This review examines how manufacturing technologies such as 3D printing, electrospinning, and microfluidic technology contribute to enhancing the therapeutic effects of these biomaterials. Following this, it provides detailed introductions to various anti-osteoporosis drug delivery systems, such as injectable hydrogels, nanoparticles, and engineered exosomes, as well as bone tissue engineering materials and coatings used in immunomodulation. Moreover, it critically analyzes the current limitations of biomaterial-mediated bone immunotherapy and explores future research directions for material-mediated bone immunotherapy. This review aims to inspire new approaches and broaden perspectives in addressing the challenges of bone repair and aging by exploring innovative biomaterial-mediated immunotherapy strategies.

Oncogenic activation of PI K3 CA in cancers: Emerging targeted therapies in precision oncology

Phosphoinositide 3-kinases (PI3Ks) are heterodimers consisting of a p110 catalytic subunit and a p85 regulatory subunit. The PIK3CA gene, which encodes the p110α, is the most frequently mutated oncogene in cancer. Oncogenic PIK3CA mutations activate the PI3K pathway, promote tumor initiation and development, and mediate resistance to anti-tumor treatments, making the mutant p110α an excellent target for cancer therapy. PIK3CA mutations occur in two hotspot regions: one in the helical domain and the other in the kinase domain. The PIK3CA helical and kinase domain mutations exert their oncogenic function through distinct mechanisms. For example, helical domain mutations of p110α gained direct interaction with insulin receptor substrate 1 (IRS-1) to activate the downstream signaling pathways. Moreover, p85β proteins disassociate from helical domain mutant p110α, translocate into the nucleus, and stabilize enhancer of zeste homolog 1/2 (EZH1/2). Due to the fundamental role of PI3Kα in tumor initiation and development, PI3Kα-specific inhibitors, represented by FDA-approved alpelisib, have developed rapidly in recent decades. However, side effects, including on-target side effects such as hyperglycemia, restrict the maximum dose and thus clinical efficacy of alpelisib. Therefore, developing p110α mutant-specific inhibitors to circumvent on-target side effects becomes a new direction for targeting PIK3CA mutant cancers. In this review, we briefly introduce the function of the PI3K pathway and discuss how PIK3CA mutations rewire cell signaling, metabolism, and tumor microenvironment, as well as therapeutic strategies under development to treat patients with tumors harboring a PIK3CA mutation.

Clinical Significance of Hematological Indices as Disease Activity Markers in Patients With Ankylosing Spondylitis Following Treatment With Tumor Necrosis Factor Inhibitors

BACKGROUND

The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) are commonly used to measure disease activity in patients with AS.

AIM

This study was conducted to determine the power of hematological indices to serve as disease activity markers in AS patients treated with tumor necrosis factor (TNF) inhibitors.

METHODS

A total of 222 patients with AS were recruited and classified into active disease (BASDAI ≥ 4, n = 158) and remission (BASDAI < 4, n = 64) groups. The active group was treated with TNF inhibitors for 3 months. Composite indices such as BASDAI and ASDAS-CRP were measured to assess disease activity. Hematological indices as alternative disease activity markers including neutrophil-to-lymphocyte ratio (NLR), neutrophil-to-hemoglobin and lymphocyte (NHL) score, systemic immune-inflammation index (SII), and platelet-to-lymphocyte ratio (PLR) were assessed.

RESULTS

Patients with active AS showed higher NLR, NHL score, SII, and PLR than those in remission. ASDAS-CRP and BASDAI values at baseline were significantly associated with all hematological indices, including NLR, NHL score, SII, and PLR. Similar to the improvement of BASDAI and ASDAS-CRP scores following TNF inhibitors treatment, NLR, NHL score, SII, and PLR markedly decreased after treatment with TNF inhibitors for 3 months (p < 0.001 for all, respectively). All hematological indices closely predicted major improvement (∆ ≥ 2.0 of ASDAS-CRP) following treatment with TNF inhibitors.

CONCLUSION

This study indicated that four hematological indices may be useful markers of disease activity and predictors of treatment response to TNF inhibitors in patients with AS. Further studies in larger populations are needed to validate the usefulness of hematological indices as measures of disease activity in patients with AS.

The Protein Kinase aPKC as Well as the Small GTPases RhoA and Cdc42 Regulates Neutrophil Chemotaxis Partly by Recruiting the ROCK Kinase to the Leading Edge

The small GTPases RhoA and Cdc42 and their effector proteins play crucial roles in neutrophil chemotaxis. However, endogenous localization and regulation of these proteins have remained largely unknown. Here, we show, using a trichloroacetic acid fixation method, that endogenous RhoA and Cdc42 are preferentially accumulated at the F-actin-rich leading edge (pseudopod) during chemotaxis of human neutrophil-like PLB-985 cells in response to the chemoattractant C5a. Interestingly, the enrichment of RhoA is impaired by knockdown of Cdc42, indicating a positive regulation by Cdc42. Depletion of Cdc42 or RhoA each induces the formation of multiple pseudopods, confirming their significance in cell polarization with an organized actin network at the front. The Rho-associated kinase ROCK is also recruited to the leading edge during chemotaxis in a manner dependent on not only RhoA and Cdc42 but also aPKC, a Cdc42-interacting kinase that can also bind to ROCK. ROCK promotes phosphorylation of the myosin light chain at the front, possibly regulating pseudopod contractility. Knockdown of aPKC suppresses neutrophil chemotaxis by disturbing pseudopod orientation without forming multiple protrusions. An incorrectly oriented pseudopod is also observed in ROCK-depleted cells. Thus, aPKC, as well as RhoA and Cdc42, likely regulates neutrophil chemotaxis partly by recruiting ROCK to the leading edge for correct directionality.

Redefining CRP in tissue injury and repair: more than an acute pro-inflammatory mediator

Most early studies investigating the role of C-reactive protein (CRP) in tissue damage determined it supported pro-hemostatic and pro-inflammatory activities. However, these findings were not universal, as other data suggested CRP inhibited these same processes. A potential explanation for these disparate observations finally emerged with the recognition that CRP undergoes context-dependent conformational changes in vivo, and each of its three isoforms - pentameric CRP (pCRP), modified pentameric CRP (pCRP*), and monomeric CRP (mCRP) - have different effects. In this review, we consider this new paradigm and re-evaluate the role of CRP and its isoforms in the tissue repair process. Indeed, a growing body of evidence points toward the involvement of CRP not just in hemostasis and inflammation, but also in the resolution of inflammation and in tissue regeneration. Additionally, we briefly discuss the shortcomings of the currently available diagnostic tests for CRP and highlight the need for change in how CRP is currently utilized in clinical practice.

The dual role of neutrophils in sepsis-associated liver injury

Sepsis is often accompanied by liver injury and is associated with an increase in the number of circulating and hepatic neutrophils. In sepsis-associated liver injury, neutrophils exhibit phenotypic heterogeneity and perform both pro- and anti-inflammatory functions. Moreover, neutrophil dysfunction and neutrophil-associated immunosuppression are also involved in the pathogenesis of sepsis. Given the complex functionality of this cell type, the aim of this review was to describe the possible mechanistic role of neutrophils in sepsis-associated liver injury, with a brief introduction to neutrophil recruitment and subsequent discussion of the potential contributions of neutrophils to different subtypes of sepsis-associated liver injury.

Neutrophils in colorectal cancer: mechanisms, prognostic value, and therapeutic implications

Neutrophils, the most abundant myeloid cells in human peripheral blood, serve as the first defense line against infection and are also significantly involved in the initiation and progression of cancer. In colorectal cancer (CRC), neutrophils exhibit a dual function by promoting tumor events and exerting antitumor activity, which is related to the heterogeneity of neutrophils. The neutrophil extracellular traps (NETs), gut microbiota, and various cells within the tumor microenvironment (TME) are involved in shaping the heterogeneous function of neutrophils. This article provides an updated overview of the complex functions and underlying mechanisms of neutrophils in CRC and their pivotal role in guiding prognosis assessment and therapeutic strategies, aiming to offer novel insights into neutrophil-associated treatment approaches for CRC.

Calycosin extracted from Astragali Radix reduces NETs formation to improve renal fibrosis via TLR4/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Astragali Radix (A. Radix) is the dry root of the leguminous plants Astragalus membranaceus (Fisch) Beg. var. mongholicus (Beg) Hsiao, and Astragalus membranaceus (Fisch) Bge., being used as a medicinal and edible resource. AR is used in traditional Chinese medicine prescriptions to treat chronic nephritis. Calycosin (CA), the primary active compound derived from Astragali Radix, shows significant antifibrotic effects in multiple organs, but the anti-renal fibrosis effect of CA is rarely reported, and the associated mechanism of action is still need to be elucidated.

AIM OF THE STUDY

The objective of this study was to investigate the protective effects of CA on the kidney against renal fibrosis and the underlying molecular mechanisms. Evaluation of the effects of CA on renal fibrosis using unilateral ureteral obstruction (UUO) mice and transforming growth factor β1 (TGF β1)-induced cell fibrosis. The mechanism of action supporting the investigated anti-renal fibrosis effects were studied by a series of biochemical experiments.

RESULTS

Our research demonstrated that CA reduced kidney cell fibrosis in mice with UUO and in TGF-β1-stimulated NRK-52E cells. Additionally, CA mitigated renal fibrosis via toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) and had a synergistic effect with resatorvid (TAK-242). Our findings revealed an unobserved impact of CA in inhibiting neutrophil extracellular traps (NETs) formation in UUO mice and neutrophils activated by phorbol 12-myristate 13-acetate.

CONCLUSIONS

Our findings revealed that calycosin reduces NETs production to alleviate renal fibrosis via TLR4 and NF-κB, supporting its potential as a strategy for treating renal fibrosis.

Periodontitis-related myocardial fibrosis by expansion of collagen-producing SiglecF+ neutrophils

BACKGROUNDS AND AIMS

Patients with periodontitis (PD) are prone to developing myocardial infarction (MI), yet the prognosis and mechanisms remain unclear. Given the presumed close association of neutrophils with both conditions, this study aims to elucidate the roles of neutrophils in mediating the interaction between PD and MI.

METHODS

Three prospective cohorts and PD + MI mouse model were investigated to assess the effects of PD on MI prognosis. Single-cell-RNA sequencing and genome-wide association study were employed to identify the neutrophil subtype involved. To characterize the function of SiglecF+ neutrophils, bone marrow transplantation, Edu-pulse chasing, lineage tracing, and collagen contraction assay were utilized. Adoptive neutrophil transfer, conditional Siglecf knockout and lipid nanoparticles facilitating local SiglecF+ neutrophils depletion was harnessed to explore the roles of SiglecF+ neutrophils in MI repair.

RESULTS

Persisting but not short-term PD upset MI prognosis (cardiac fibrosis and function) in human and mice. Bone marrow neutrophils of PD were intrinsically skewed toward longer-lived SiglecF+ neutrophil differentiation, a subtype that was converted by GMCSF or TGFβ in PPARγ-dependent manner. SiglecF+ neutrophils were expanded in infarcted PD heart where they deposit collagen and activate fibroblasts to instigate excessive fibrosis. SiglecF+ neutrophil depletion was efficacious for mitigating fibrosis.

CONCLUSIONS

This study demonstrated that long-lasting PD-aggravated MI prognosis by expanding scar-associated SiglecF+ neutrophils into the heart and highlighted the clinical relevance of oral health examination for treating MI in a holistic fashion.

Gαq/11 aggravates acute lung injury in mice by promoting endoplasmic reticulum stress-mediated NETosis

BACKGROUND

Acute lung injury (ALI) is distinguished by exaggerated neutrophil extracellular traps (NETs), elevated clinical mortality rates, and a paucity of targeted therapeutic interventions. The Gαq/11 protein, a member of the G protein subfamily, is an effective intervention target for a variety of diseases, but little is known about its role in ALI.

METHODS

In this study, a murine model of ALI induced by lipopolysaccharide (LPS) was utilized, employing myeloid cell-specific Gna11 knockout mice. The pulmonary pathology of mice was assessed and the lung samples were collected for immunofluorescence staining and RNA-sequencing analysis to elucidate the impact and underlying mechanisms of Gαq/11 in ALI. Mouse bone marrow-derived neutrophils were isolated and cultured for live-cell imaging to investigate the in vitro effects of Gαq/11.

RESULTS

The expression of Gαq/11 was found to be upregulated in the lung tissues of mice with ALI, coinciding with the increased expression of inflammatory genes. Myeloid cell-specific Gna11 deficience attenuated LPS-induced lung injury and the formation of NETs in mice. Mechanistically, Gαq/11 facilitates NETosis by promoting the activation of the endoplasmic reticulum (ER) stress sensor IRE1α in neutrophils and mediating the production of mitochondrial reactive oxygen species (mitoROS). Pharmacological inhibition of Gαq/11 using YM-254,890 was shown to reduce NETs formation and lung injury in mice.

CONCLUSIONS

The upregulation of Gαq/11 exacerbates ALI through the promotion of ER stress-mediated NETosis. Consequently, Gαq/11 represents a potential therapeutic target for the treatment of ALI.

Squaraine-Peptide Conjugates as Efficient Reporters of Neutrophil Extracellular Traps-Mediated Chronic Inflammation

The excessive and uncontrolled release of neutrophil extracellular traps (NETs) is increasingly linked to the pathogenesis of various inflammatory diseases, cardiovascular disorders, and cancers. Real-time, non-invasive detection of NETs is crucial for understanding their role in disease progression and developing targeted therapies. Current NETs detection methods often lack the necessary specificity and resolution, particularly in vivo and ex vivo settings. To address this, we have developed novel near-infrared squaraine-peptide conjugates by rational molecular design as reporters of NETosis by targeting the protease activity of neutrophil elastase (NE). These self-quenching, cell-impermeable probes enable the precise real-time detection and imaging of NETs. The Förster resonance energy transfer (FRET)-based probe, Hetero-APA, demonstrated high specificity in detecting NETs in vitro and in vivo, generating strong fluorescence in NETs-rich environments. To overcome the limitations of FRET-based probes for ex vivo imaging, we designed SQ-215-NETP, a non-FRET-based probe that covalently binds to the NE. SQ-215-NETP achieved an unprecedented imaging resolution of 90 nm/pixel in human coronary thrombi, marking the first report of such high resolution with a low molecular weight probe. Additionally, SQ-215-NETP effectively detected NETs by flow cytometry. These results highlight the potential of these probes in NETosis detection, offering promising tools for enhanced diagnostics and therapeutic strategies in managing NET-mediated inflammatory diseases and cancers.

β2 integrin regulates neutrophil trans endothelial migration following traumatic brain injury

Neutrophils are the first responders among peripheral immune cells to infiltrate the central nervous system following a traumatic brain injury (TBI), triggering neuroinflammation that can exacerbate secondary tissue damage. The precise molecular controls that dictate the inflammatory behavior of neutrophils post-TBI, however, remain largely elusive. Our comprehensive analysis of the molecular landscape surrounding the trauma in TBI mice has revealed a significant alteration in the abundance of β2 integrin (ITGB2), predominantly expressed by neutrophils and closely associated with immune responses. Using the fluid percussion injury (FPI) mouse model, we investigated the therapeutic efficacy of Rovelizumab, an agent that blocks ITGB2. The treatment has demonstrated significant improvements in neurologic function in TBI mice, attenuating blood-brain barrier permeability, mitigating oxidative stress and inflammatory mediator release, and enhancing cerebral perfusion. Moreover, ITGB2 blockade has effectively limited the adherence, migration, and infiltration of neutrophils, and has impeded the formation of neutrophil extracellular traps (NETs) upon their activation. Finally, it was demonstrated that ITGB2 mediates these effects mainly through its interaction with intercellular adhesion molecule-1 (ICAM 1) of endotheliocyte. These findings collectively illuminate ITGB2 as a crucial molecular switch that governs the adverse effects of neutrophils post-TBI and could be targeted to improve clinical outcome in patients.

Higher systemic immune-inflammation index is associated with increased risk of Parkinson's disease in adults: a nationwide population-based study

Background

This study aimed to explore the association between a new inflammatory marker, systemic immune-inflammation index (SII), and the risk of Parkinson's disease (PD) in adult population.

Methods

A cross-sectional design was used, participants were recruited from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2020. Three logistic regression models were used to explore the association between SII and the risk of PD, and subgroup analysis and sensitivity analysis were used. In addition, the restricted cubic spline (RCS) was used to explore the dose-response relationship between SII and PD. Receiver operating characteristic (ROC) curves was used to explore the diagnostic value of SII for PD.

Results

A total of 54,027 adults (mean age 35 years) were included in this study. The results of logistic regression showed that after adjusted for all covariates, compared with the Q1 group (lowest quartile in SII), the risk of PD in the Q3 group (OR = 1.82, 95%CI = 1.20-2.82, p < 0.001) and the Q4 group increased (OR = 2.49, 95%CI = 1.69-3.77, p < 0.001), with p-trend < 0.001. After excluding individuals with any missing values, sensitivity analysis also found a positive association between SII and PD. Subgroup analysis showed that this association was more significant in women, younger than 60 years old, non-smokers, alcohol drinkers, non-obese, and without a history of stroke, diabetes, or coronary heart disease. In addition, there was a positive dose-response relationship between SII and PD, and SII had an acceptable diagnostic value for PD (AUC = 0.72).

Conclusion

SII is positively correlated with the prevalence of PD in the adult population, and SII can help differentiate between PD and non-PD cases.

Harnessing amino acid pathways to influence myeloid cell function in tumor immunity

Amino acids are pivotal regulators of immune cell metabolism, signaling pathways, and gene expression. In myeloid cells, these processes underlie their functional plasticity, enabling shifts between pro-inflammatory, anti-inflammatory, pro-tumor, and anti-tumor activities. Within the tumor microenvironment, amino acid metabolism plays a crucial role in mediating the immunosuppressive functions of myeloid cells, contributing to tumor progression. This review delves into the mechanisms by which specific amino acids-glutamine, serine, arginine, and tryptophan-regulate myeloid cell function and polarization. Furthermore, we explore the therapeutic potential of targeting amino acid metabolism to enhance anti-tumor immunity, offering insights into novel strategies for cancer treatment.

Forward programming of hPSCs to neutrophils using chemically defined media

Polymorphonuclear neutrophils (PMNs), the most abundant leukocytes circulating in human blood, are pivotal players in the innate immune system. In recent years, PMNs have gained increasing recognition for their significant involvement in the pathogenesis of a wide array of human diseases, including sepsis, pulmonary conditions, autoimmune disorders, and various cancers. Due to their terminally differentiated state, PMNs possess a short lifespan and exhibit limited proliferative potential, which makes continuous replenishment from the bone marrow essential for maintaining immune homeostasis. This demand underscores the need for efficient, reliable, and robust methods of PMN production. In this study, we evaluated three forward programming protocols and one directed differentiation protocol aimed at generating PMNs from human pluripotent stem cells (hPSCs). We analyzed not only their differentiation efficiency but also the transcriptomic profiles and functional capabilities of the resulting PMNs. Our findings revealed that both the forward programming method and the directed differentiation approach can successfully generate functional PMNs. Furthermore, by fine-tuning the culture media at various stages during forward programming, we identified an optimal protocol that significantly enhances hematopoietic differentiation potential and promotes the functional maturity of the neutrophils.

A surface protein identified from Streptococcus suis serotype 2 exhibits neutrophil-resistant ability via its polysaccharide capsule

Streptococcus suis serotype 2 (SS2) is an emerging zoonotic agent responsible for a variety of diseases. The septicemia caused by SS2 suggests that it can evade the bactericidal effects of innate immune cells. However, the mechanisms by which SS2 evades innate immunity remain largely unknown. Neutrophils are critical components of innate immunity for antimicrobial defense. In this study, we identified a cell surface protein (CSP) insertion mutant in an SS2 transposon mutant library that significantly induces neutrophil extracellular traps (NETs) and shows poor survival compared to the parent SS2 in the bloodstream. CSP deletion mutant (ΔCSP) was constructed and it exhibits a defective polysaccharide capsule and enhanced biofilm formation. Although ΔCSP induces increased NET release and ROS formation, its survival and proliferation within neutrophils and NETs are significantly reduced. Additionally, ΔCSP stimulates extracellular signal-regulated kinase 1/2 (ERK1/2) signaling in neutrophils, which may enhance neutrophil bactericidal activity. Importantly, purified polysaccharide capsule from SS2 can inhibit neutrophil bactericidal effects. This study identifies bacterial virulence factors that prevent SS2 clearance by neutrophils, offering potential antigens or drug targets for the prevention and control of swine streptococcosis.

Inhibition mechanism of leukemia cells HL-60 by exopolysaccharides from Botryococcus braunii in response to high-concentration cobalt

The influence of metal elements on the biomedical activity of microalgal exopolysaccharides (EPS) remains underexplored. This study examined the antitumor properties of Botryococcus braunii EPS under high cobalt conditions and the role of exogenous 3-indole acetic acid (IAA) in enhancing its activity. Results showed that IAA mitigated cobalt-induced inhibition of B. braunii growth and improved its antioxidant capacity. Notably, EPS obtained from B. braunii treated with IAA under high cobalt conditions (HC-IAA-EPS) exhibited a 98.06 % inhibition of human promyelocytic leukemia cells (HL-60), significantly higher than the control (83.86 %). HC-IAA-EPS induced mitochondrial damage in HL-60 cells, evidenced by a decrease in mitochondrial transmembrane potential (observed via fluorescence microscopy) and a 1.5-fold increase in reactive oxygen species (ROS) levels compared to the control, ultimately triggering endogenous apoptosis. Proteomic analysis revealed that HC-IAA-EPS caused significant changes in apoptosis and cell cycle-related protein changes in HL-60. Gene Ontology (GO) analysis indicated enrichment in pathways such as neutrophil degranulation, Toll-like receptor (TLR) signaling, and vesicle binding complexes. This study concludes that HC-IAA-EPS inhibits HL-60 cell proliferation by inducing mitochondrial dysfunction, reducing transmembrane potential, and increasing ROS production, providing valuable insights into the antitumor potential of microalgal EPS under metal stress conditions.

Evaluating the Efficacy of Gelatin-Chitosan-Tetraethyl Orthosilicate Calcium Hydroxide Composite as a Dental Pulp Medicament on COX-2, PGP 9.5, TNF-α Expression and Neutrophil number

Introduction

Calcium hydroxide (Ca(OH) 2) is the material of choice for pulp therapy. However, Ca(OH) 2 has drawbacks such as toxicity, poor sealing, and tunnel defect formation. Alternative materials have been developed to provide more biocompatible materials with better dentin formation ability. The objective of this study was to evaluate the effect of composites containing gelatin (G), chitosan (CH), tetraethyl orthosilicate (TEOS), and Ca(OH) 2, namely G-CH-TEOS-Ca (OH) 2 (Extended data) on inflammation of the dental pulp (expression of COX-2, PGP 9.5, TNF-α, and neutrophil number).

Materials and methods

A total of 16 Wistar rat models of acute pulp injury were prepared and divided into two groups, treatment and control, 8 with each. In the treatment group, we applied a pulp-capping material using G-CH-TEOS-Ca (OH) 2 and Ca(OH) 2. On the 1 st and 3 rd days, rats were sacrificed. Tissue samples from 4 rats in each group were processed for histological preparation. COX-2, PGP 9.5, and TNF-α were observed using immunohistochemical (IHC) staining, and neutrophil numbers were observed using hematoxylin-eosin staining. Image analysis of COX-2, PGP 9.5, and TNF-α expression was performed using ImageJ software.

Results

The results showed a decrease in COX-2 expression, but not significantly while PGP 9.5 and TNF-α expression were significantly higher than those in the control group. Neutrophil numbers were lower in the treatment group than in the control group, but the difference was not statistically significant.

Conclusion

The G-CH-TEOS-Ca (OH) 2 composite material may have potential as an exposed pulp medicament by reducing inflammation (COX-2 expression and number of neutrophils) and increasing the regeneration factor (TNF-α expression) and nerve (PGP 9.5 expression).

Vaccine Specifically for Immunocompromised Individuals against Superbugs

Immunocompromised populations, including cancer patients, elderly individuals, and those with chronic diseases, are the primary targets of superbugs. Traditional vaccines are less effective due to insufficient or impaired immune cells. Inspired by the "vanguard" effect of neutrophils (NE) during natural infection, this project leverages the ability of NE to initiate the NETosis program to recruit monocytes and DC cells, designing vaccines that can rapidly recruit immune cells and enhance the immune response. The PLGA microsphere vaccine platform (MSV) with a high level of safety contains whole-bacterial antigens both internally and externally, providing initial and booster effects through programmed distribution and release of antigens after a single injection. Experimental data indicate that immunizing mice with a mixture of MSV and NE induces the formation of spontaneous gel-like neutrophil extracellular traps (NETs) at the inoculation site. These NETs recruit immune cells and prevent the diffusion of vaccine components, thereby reducing damage from bacterial toxins and enhancing vaccine biosafety. This strategy shows excellent efficacy against MRSA-induced infections in not only healthy but also immunocompromised mice.

Microplastics in the bloodstream can induce cerebral thrombosis by causing cell obstruction and lead to neurobehavioral abnormalities

Human health is being threatened by environmental microplastic (MP) pollution. MPs were detected in the bloodstream and multiple tissues of humans, disrupting the regular physiological processes of organs. Nanoscale plastics can breach the blood-brain barrier, leading to neurotoxic effects. How MPs cause brain functional irregularities remains unclear. This work uses high-depth imaging techniques to investigate the MPs within the brain in vivo. We show that circulating MPs are phagocytosed and lead these cells to obstruction in the capillaries of the brain cortex. These blockages as thrombus formation cause reduced blood flow and neurological abnormalities in mice. Our data reveal a mechanism by which MPs disrupt tissue function indirectly through regulation of cell obstruction and interference with local blood circulation, rather than direct tissue penetration. This revelation offers a lens through which to comprehend the toxicological implications of MPs that invade the bloodstream.

The success of the tumor immunotherapy: neutrophils from bench to beside

The present immune therapy was focused on the immune checkpoint blockade or Chimeric Antigen Receptor T-Cell Immunotherapy (CART) transfer, but how to activate the innate immune system to antitumor still lags out. Neutrophils are the most abundant circulating leukocytes in human, and heterogeneous neutrophils have been increasingly recognized as important players in tumor progression. They play double "edge-sward" by either supporting or suppressing the tumor growth, including driving angiogenesis, extracellular matrix remodeling to promote tumor growth, participating in antitumor adaptive immunity, or killing tumor cells directly to inhibit the tumor growth. The complex role of neutrophils in various tumors depends on the tumor microenvironment (TME) they are located, and emerging evidence has suggested that neutrophils may determine the success of tumor immunotherapy in the context of the immune checkpoint blockade, innate immune training, or drug-loaded extracellular microvesicles therapy, which makes them become an exciting target for tumor immunotherapy, but still with challenges. Here, we summarize the latest insights on how to activate neutrophils in antitumor immunity and discuss the advances of neutrophil-targeted immunotherapy strategies.

Neutrophil extracellular traps potentiate effector T cells via endothelial senescence in uveitis

Autoimmune uveitis (AU) is a sight-threatening ocular autoimmune disorder that often manifests as retinal vasculitis. Increased neutrophil infiltration around retinal vessels has been reported during the progression of AU, while how they function is not fully recognized. Neutrophil extracellular traps (NETs), produced by activated neutrophils, have been suggested to be detrimental in autoimmune diseases. Here, we found that NETs were elevated in patients with active AU, and this was verified in an experimental AU (EAU) mouse model. Depletion of neutrophils or degradation of NETs with deoxyribonuclease-I (DNase I) could decrease CD4+ effector T cell (Teff) infiltration in retina and spleen to alleviate EAU. Moreover, we found that the expression of adhesion molecules, selectin, and antigen-presenting molecules was elevated in EAU retina and in retinal microvascular endothelial cells (RMECs) cocultured with NETs. The stimulated RMECs further facilitated CD4+ T cell adhesion, activation, and differentiation into Teffs. Mechanistically, NETs trigger RMEC activation by hastening cell senescence through the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway. Slowing down senescence or inhibiting the cGAS/STING pathway in RMECs reduces the activation and differentiation of CD4+ T cells. These results suggest a deleterious role of NETs in AU. Targeting NETs would offer an effective therapeutic method.

Meningeal neutrophil immune signaling influences behavioral adaptation following threat

Social creatures must attend to threat signals from conspecifics and respond appropriately, both behaviorally and physiologically. In this work, we show in mice a threat-sensitive immune mechanism that orchestrates psychological processes and is amenable to social modulation. Repeated encounters with socially cued threats triggered meningeal neutrophil (MN) priming preferentially in males. MN activity was correlated with attenuated defensive responses to cues. Canonical neutrophil-specific activation marker CD177 was upregulated after social threat cueing, and its genetic ablation abrogated male behavioral phenotypes. CD177 signals favored meningeal T helper (Th)1-like immune bias, which blunted neural response to threatening stimuli by enhancing intrinsic GABAergic inhibition within the prelimbic cortex via interferon-gamma (IFN-γ). MN signaling was sensitized by negative emotional states and governed by socially dependent androgen release. This male-biased hormone/neutrophil regulatory axis is seemingly conserved in humans. Our findings provide insights into how immune responses influence behavioral threat responses, suggesting a possible neuroimmune basis of emotional regulation.

Advances in Engineering Myeloid Cells for Cell Therapy Applications

Myeloid cells, including macrophages, neutrophils, dendritic cells, and myeloid-derived suppressor cells, play crucial roles in the innate immune system, contributing to immune defense, tissue homeostasis, and organ development. They have tremendous potential as therapeutic tools for diseases such as cancer and autoimmune disorders, but harnessing cell engineering strategies to enhance potency and expand applications is challenging. Recent advancements in stem cell research have made it possible to differentiate human embryonic stem cells and induce pluripotent stem cells into various cell types, including myeloid cells, offering a promising new approach to generate myeloid cells for cell therapy. In this review, we explore the latest techniques for the genetic engineering of myeloid cells, discussing both established and emerging methodologies. We examine the challenges faced in this field and the therapeutic potential of engineered myeloid cells. We also describe examples of engineered macrophages, neutrophils, and dendritic cells in various disease contexts. By providing a detailed overview of the current state and future directions, we aim to highlight progress and ongoing efforts toward harnessing the full therapeutic potential of genetically engineered myeloid cells.

Neutrophil extracellular DNA traps activate the TLR9 signaling pathway of pancreatic ductal epithelial cells in patients with type 2 autoimmune pancreatitis

The presence of neutrophil infiltration around the pancreatic ducts has been found to be associated with type 2 autoimmune pancreatitis (AIP). However, the functional role and clinical significance of neutrophil migration in the progression of pancreatitis is not fully understood. Here, we found that neutrophil extracellular traps (NETs) are abundant around the pancreatic duct in patients with type 2 AIP. We also observed an increased expression of toll-like receptor 9 (TLR9) in pancreatic ductal epithelial cells (HPDEC) in type 2 AIP patients compared to other pancreatic diseases. TLR9 acts as the DNA component of NETs (NET-DNA) receptor in HPDEC, which senses extracellular DNA and subsequently activates the NF-κB pathway to promote neutrophil recruitment and induce NET formation. In addition, our results indicated that the hydroxychloroquine (HCQ), acting as a TLR9 antagonist, could effectively inhibit the activation of inflammatory pathways, reduce neutrophil migration and block the positive feedback loop. The intervention positions HCQ acts as a potential target drug for the clinical treatment of type 2 AIP.

Single-cell analysis of peri-implant gingival tissue to assess implant biocompatibility and immune response

PURPOSE

The innate immune response, particularly the reaction of polymorphonuclear neutrophils (PMNs), is crucial in shaping the outcomes of chronic inflammation, fibrosis, or osseointegration following biomaterial implantation. Peri-implantitis or peri-implant mucositis, inflammatory conditions linked to dental implants, pose a significant threat to implant success. We developed a single-cell analysis approach using a murine model to assess the immune response to implant materials, offering a practical screening tool for potential dental implants.

METHODS

We performed bioinformatics analysis and established a peri-implant inflammation model by inserting two titanium implants into the maxillary region, to examine the immune response.

RESULTS

Bioinformatics analysis revealed that titanium implants triggered a host immune response, primarily mediated by PMNs. In the in vivo experiments, we observed a rapid PMN-mediated response, with increased infiltration around the implants and on the implant surface by day 3. Remarkably, PMN attachment to the implants persisted for 7 days, resembling the immune profiles seen in human implant-mediated inflammation.

CONCLUSIONS

Our findings indicate that persistent attachment of the short-living PMNs to titanium implants can serve as an indicator or traits of peri-implant inflammation. Therefore, analyzing gingival tissue at the single-cell level could be a useful tool for evaluating the biocompatibility of candidate dental implants.

Relationship between postablation fever and prognosis in initial hepatocellular carcinoma: a 15-year multicenter, retrospective cohort study

BACKGROUND

Fever is a common side effect following thermal ablation in patients with hepatocellular carcinoma (HCC), yet its impact on prognosis remains unclear.

MATERIALS AND METHODS

This retrospective study included initial HCC patients who underwent US-guided percutaneous microwave ablation at 13 hospitals between January 2006 and February 2021. All patients were categorized into afebrile, transient low-grade fever (TLF), and prolonged or high-grade fever (PHF) groups. Primary outcomes included very early recurrence (VER) and early recurrence (ER), secondary outcomes were disease-free survival (DFS) and overall survival (OS). Fever cut-offs for VER/ER were established using restrictive cubic splines and an adjusted Cox model. Survival analyses used the Kaplan-Meier method.

RESULTS

A total of 1458 initial HCC patients (mean age, 59±11[SD]; 1146 men). Compared to afebrile individuals, patients with TLF (temperatures ranging 37.0-38.8°C for 1-2 days), showed independent protective effects against VER (HR, 0.73; 95% CI: 0.57-0.95; P =0.02) and ER (HR, 0.66; 95% CI: 0.54-0.81; P <0.001), however, PHF showed no differences in VER (HR, 0.99; 95% CI: 0.76-1.30; P =0.96) and ER (HR, 0.86; 95% CI: 0.69-1.07; P =0.17). With a median follow-up of 47 months (IQR: 26-79), the median DFS for TLF patients was 40 months, superior to afebrile (30 months, P =0.019) and PHF patients (33 months, P =0.049). The 5-year OS rate for TLF patients was 73.2%, higher than afebrile (69.3%, P =0.02) and PHF patients (66.7%, P =0.03). No significant difference was found in DFS and OS between afebrile and PHF patients ( P =0.90 and 0.71). Notably, TLF patients exhibited the highest lymphocyte counts increasing median 7 days after ablation ( P <0.001 vs. afebrile and P =0.01 vs. PHF).

CONCLUSION

Transient low-grade fever following percutaneous microwave ablation in hepatocellular carcinoma patients demonstrated protection against early recurrence, possibly attributed to the short-term activation of lymphocytes.

The heterogeneity of neutrophils in cancer and its implication for therapeutic targeting

Neutrophils have a pivotal role in safeguarding the host against pathogens and facilitating tissue remodeling. They possess a large array of tools essential for executing these functions. Neutrophils have a critical role in cancer, where they are largely associated with negative clinical outcome and resistance to therapy. However, the specific role of neutrophils in cancer is complex and controversial, owing to their high functional diversity and acute sensitivity to the microenvironment. In this Perspective, we discuss the accumulated evidence that suggests that the functional diversity of neutrophils can be ascribed to two principal functional states, each with distinct characteristics: classically activated neutrophils and pathologically activated immunosuppressive myeloid-derived suppressor cells. We discuss how the antimicrobial factors in neutrophils can contribute to tumor progression and the fundamental mechanisms that govern the pathologically activated myeloid-derived suppressor cells. These functional states play divergent roles in cancer and thus require separate consideration in therapeutic targeting.

Integrative Transcriptomic Analysis of Peripheral Blood Monocytes in Systemic Sclerosis and Shared Pathogenic Pathways in Autoimmune Diseases

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disease (AD), that receives less attention compared to rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and primary Sjögren's syndrome (pSS). This study aims to analyze transcriptional profiles and immune cell composition in peripheral blood mononuclear cells (PBMC) from SSc patients compared to other ADs.

METHODS

RNA-seq data from 119 untreated patients (eight with SSc, 42 with RA, 41 with pSS, 28 with SLE) and 20 healthy controls were analyzed. Bioinformatics tools were employed to identify differentially expressed genes (DEGs), biological functions and immune cell profiles unique to SSc and shared with other ADs.

RESULTS

1,148 DEGs were found in SSc, with upregulated genes associated with megakaryocyte processes and downregulated genes associated with neutrophil function and immune response. DEGs, including ALDH1A1 and MEGF9, were associated with neutropenia. Upregulated transcription factors (TFs) were linked to embryonic hematopoiesis and downregulated TFs were involved in leukocyte differentiation and immune regulation. Comparative analysis with other ADs revealed common pathogenic pathways, emphasizing megakaryocyte proliferation. Neutrophils count was significantly decreased in ADs (p <0.001) compared to healthy controls. Comparative analysis highlighted common pathways, particularly in megakaryocyte proliferation, and unique genes (MEGF9, MMP8, and KRT family members) in SSc, suggesting roles in neutrophil function, skin integrity, and fibrosis.

CONCLUSIONS

This study identifies dysregulated gene expression (KRT and MMP8) associated with neutrophil function and increased megakaryocytes in SSc, highlighting common patterns across autoimmune diseases. These findings offer new insights into the potential pathogenesis of SSc, and help to explore new targets for the treatment.

Formation of aggregated neutrophil extracellular traps in tissues is determining the efficacy of particulate nanoadjuvants

Neutrophils are essential for innate immunity, using mechanisms like Neutrophil Extracellular Trap (NET) formation to fight pathogens. Aggregated NETs (aggNETs) help resolve inflammation by cleaving pro-inflammatory cytokines, while scattered NETs can exacerbate inflammation, leading to tissue damage. Co-injection of 10 nm nanodiamonds (ND10) with peptide antigens boosts immune responses, including anti-SARS-CoV-2 immunity, due to transient immune responses induced by aggNETs around ND10 particles. Diamond nanoparticles in adjuvant mixtures enhance vaccines, though the optimal dose is uncertain. Our study aimed to find the minimal ND10 amount needed for effective aggNETs formation and a robust immune response with minimal long-term tissue damage. In vivo experiments revealed 1 mg of ND10 per injection significantly enhances immune responses, forming granulomas rich in neutrophil elastase. Lower doses left scattered nanoparticles, insufficient for aggNETs formation. The effective ND10 dose for mice, 1 mg per injection, can be extrapolated to other organisms.

Effect of neutrophils on tumor immunity and immunotherapy resistance with underlying mechanisms

Neutrophils are key mediators of the immune response and play essential roles in the development of tumors and immune evasion. Emerging studies indicate that neutrophils also play a critical role in the immunotherapy resistance in cancer. In this review, firstly, we summarize the novel classification and phenotypes of neutrophils and describe the regulatory relationships between neutrophils and tumor metabolism, flora microecology, neuroendocrine and tumor therapy from a new perspective. Secondly, we review the mechanisms by which neutrophils affect drug resistance in tumor immunotherapy from the aspects of the immune microenvironment, tumor antigens, and epigenetics. Finally, we propose several promising strategies for overcoming tumor immunotherapy resistance by targeting neutrophils and provide new research ideas in this area.

Dapsone Alters Phenotypical and Functional Properties of Human Neutrophils In Vitro

Dapsone is a sulfone used in treating inflammatory skin conditions. Despite its widespread dermatological use, the pharmacological actions of dapsone remain poorly understood. Here, we examined how different aspects of neutrophil functions are affected by dapsone. Peripheral blood neutrophils from healthy donors were stimulated with phorbol-12-myristate-13-acetate (PMA), N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), or calcium ionophore (CaI) or primed with cytokines prior to stimulation, in the presence of different concentrations of dapsone (from 10 to 50 µg/mL), followed by analyses of their survival, phenotype, and functional properties. We found that dapsone at the concentration of 50 μg/mL induced a significant neutrophil apoptotic rate during 6 h and 18 h, while other concentrations were well tolerated compared to control non-treated cells. However, dapsone significantly decreased the induced oxidative burst of neutrophils at all non-cytotoxic concentrations. Additionally, dapsone showed a dose-dependent suppression of NETosis in activated neutrophils. The production of IL-8 by dapsone-treated neutrophils was decreased under both stimulated (fMLP) and primed (TNF-α/fMLP) conditions. Moreover, dapsone inhibited the expression of CD11b/CD18, CD66, and CD89 and reversed or significantly mitigated the downregulation of CD16, CD32, CD181, CD88, and CD62L on neutrophils after priming and fMLP stimulation. In conclusion, our results indicate the complexity of dapsone actions on neutrophil functions, extending previous knowledge on the suppression of oxidative burst and IL-8 production upon neutrophils' activation. Suppressed NETosis and modulation of marker expression associated with different neutrophil functions under inflammatory conditions are new findings, not recognized previously.

Tumor metastasis and recurrence: The role of perioperative NETosis

Although surgical resection of tumor mass remains the mainstay of curative therapeutic management for solid tumors, accumulating studies suggest that these procedures promote tumor recurrence and metastasis. Regarded as the first immune cells to fight against infectious or inflammatory insults from surgery, neutrophils along with their ability of neutrophil extracellular traps (NETs) production has attracted much attention. A growing body of evidence suggests that NETs promote cancer metastasis by stimulating various stages, including local invasion, colonization, and growth. Therefore, we discussed the mechanism of NETosis induced by surgical stress and tumor cells, and the contribution of NETs on tumor metastasis: aid in the tumor cell migration and proliferation, evasion of immune surveillance, circulating tumor cell adhesion and establishment of a metastatic niche. Lastly, we summarized existing NET-targeting interventions, offering recent insights into potential targets for clinical intervention.

Bovine PMN responses to extracellular vesicles released by Besnoitia besnoiti tachyzoites and B. besnoiti-infected host cells

Bovine besnoitiosis is a re-emerging cattle disease caused by the apicomplexan parasite Besnoitia besnoiti, which severely affects individual animal welfare and profitability in cattle industry. We recently showed that B. besnoiti tachyzoite exposure to bovine polymorphonuclear neutrophils (PMN) effectively triggers neutrophil extracellular trap (NET) formation, leading to parasite immobilization hampering host cell infection. So far, the triggers of this defense mechanism remain unclear. Emerging evidence indicates that extracellular vesicles (EVs) modulate PMN effector functions, such as ROS production or NET formation. Therefore, we tested whether exposure of bovine PMN to EVs from different cellular sources affects classical PMN effector functions and cytokine/chemokine secretion. EVs were isolated from B. besnoiti-infected and non-infected host cells (bovine umbilical vein endothelial cells, BUVEC), from tachyzoite-exposed bovine PMN and from B. besnoiti tachyzoites. EV concentration and size was determined by Nano-Flow cytometry and EV nature was confirmed by both classical EV markers (CD9 and CD81) and transmission electron microscopy (TEM). Overall, PMN stimulation with both BUVEC- and tachyzoite-derived EVs significantly induced extracellular DNA release while EVs from PMN failed to affect NET formation. BUVEC and tachyzoite EV-driven NET formation was confirmed microscopically by the presence of DNA decorated with neutrophil elastase (NE) and histones in typical NET structures. Moreover, confocal microscopy revealed EVs to be internalized by bovine PMN. Referring to PMN activation, EVs from the different cellular sources all failed to affect glycolytic or oxidative responses of bovine PMN as detected by Seahorse®-based analytics and luminol-based chemoluminescence, thereby denying any role of NADPH oxidase (NOX) activity in EV-driven NET formation. Finally, exposure to B. besnoiti-infected BUVEC-derived EVs induced IL-1β and IL-6 release, but failed to drive CXCL8 release of bovine PMN. Hence, we overall demonstrated that EVs of selected cellular origin owned the capacity to trigger NOX-independent NET formation, were incorporated by PMN and selectively fostered IL-1β and IL-6 release.

Balancing immune response: SHP1 controls neutrophil activation in inflamed lungs

Following respiratory infection or injury, neutrophil hyperactivation can damage surrounding lung tissue by releasing harmful compounds. In this issue of the JCI, Moussavi-Harami and colleagues identified tyrosine phosphatase SHP1 as a key negative regulator of neutrophil activation in acute respiratory distress syndrome (ARDS). Neutrophil-specific Shp1 disruption leads to hyperinflammation, pulmonary hemorrhage, and increased mortality in both sterile and pathogen-induced acute lung injury (ALI). Large intravascular neutrophil clusters and excessive PAD4-independent neutrophil extracellular traps (NETs) were identified as key features of lung injury. Mechanistically, Shp1 deficiency resulted in uncontrolled SYK kinase activation, driving chaotic neutrophil hyperactivation and inflammation.

Interferon-α Inhibits NET Formation in Neutrophils Derived from Patients with Myeloproliferative Neoplasms in a Neutrophil Sub-Population-Specific Manner

Neutrophils and neutrophil extracellular traps (NETs) contribute to thrombosis and hyperinflammation in myeloproliferative neoplasms (MPN). High-density neutrophils (HDNs) and low-density neutrophils (LDNs) have recently been characterized as distinct neutrophil sub-populations with distinct morphological and functional properties. We aim to study the kinetics of NET formation and inhibition with interferon-α (IFNα) in neutrophils derived from patients with MPN as compared to matched healthy controls. Ex vivo NET formation was assessed by neutrophil-elastase activity, neutrophil-associated nucleosomes, myeloperoxidase (MPO), and citrullinated histone H3 content. IFNα significantly inhibited NET formation in neutrophils derived from MPN patients. Neutrophil sub-population analysis demonstrated that HDNs drive the increase in NET formation as compared to LDNs in patients and in healthy controls and are effectively inhibited by IFNα, an effect that is lost in LDNs. In conclusion, we demonstrate that in MPN, HDNs drive excess NET formation and are more sensitive to IFNα inhibition. These observations uncover unique neutrophil sub-population biology and dynamics in MPN.

KSRP Deficiency Attenuates the Course of Pulmonary Aspergillosis and Is Associated with the Elevated Pathogen-Killing Activity of Innate Myeloid Immune Cells

The mRNA-binding protein KSRP (KH-type splicing regulatory protein) is known to modulate immune cell functions post-transcriptionally, e.g., by reducing the mRNA stability of cytokines. It is known that KSRP binds the AU-rich motifs (ARE) that are often located in the 3'-untranslated part of mRNA species, encoding dynamically regulated proteins as, for example, cytokines. Innate myeloid immune cells, such as polymorphonuclear neutrophils (PMNs) and macrophages (MACs), eliminate pathogens by multiple mechanisms, including phagocytosis and the secretion of chemo- and cytokines. Here, we investigated the role of KSRP in the phenotype and functions of both innate immune cell types in the mouse model of invasive pulmonary aspergillosis (IPA). Here, KSRP-/- mice showed lower levels of Aspergillus fumigatus conidia (AFC) and an increase in the frequencies of PMNs and MACs in the lungs. Our results showed that PMNs and MACs from KSRP-/- mice exhibited an enhanced phagocytic uptake of AFC, accompanied by increased ROS production in PMNs upon stimulation. A comparison of RNA sequencing data revealed that 64 genes related to inflammatory and immune responses were shared between PMNs and MACs. The majority of genes upregulated in PMNs were involved in metabolic processes, cell cycles, and DNA repair. Similarly, KSRP-deficient PMNs displayed reduced levels of apoptosis. In conclusion, our results indicate that KSRP serves as a critical negative regulator of PMN and MAC anti-pathogen activity.

Effect of oxymatrine on neutrophil function based on zebrafish inflammation model and primary neutrophil inflammatory responses

Sophora flavescens Ait. (SFA), an extensively utilized herb for the treatment of fevers, inflammatory disorders, ulcers and skin diseases related to bur, contains oxymatrine (OMT) as its principal active constituent. OMT exerts regulatory effects over inflammation, oxidative stress and apoptosis. Neutrophils, critical regulators of the inflammation response, have not been thoroughly elucidated regarding the protective properties and underlying mechanisms of OMT-mediated anti-inflammation. This study was aim to explore the protective effect of OMT on neutrophils under inflammatory conditions and delve into its potential mechanism. Leveraging the advantages of zebrafish, an animal model with a real-time dynamic observation system, we established an in vivo caudal fin wound model and a copper sulfate induced-inflammation model in zebrafish line Tg (mpx:GFP). The result revealed that OMT significantly attenuated neutrophil migration, upregulated the mRNA expression levels of JNK, casp3, mapk14a, mapkapk2a and map2k1 damaged by zebrafish caudal fin wound model, and downregulated mRNA expression levels of JNK, casp3, mapk14a, mapkapk2a and map2k1 in the copper sulfate injury model. In vitro experiments demonstrated that OMT modulated the chemotaxis response of primary neutrophils from mice, enhanced phagocytosis, reduced oxidative stress and alleviated inflammation level. We hypothesize that the OMT may exert its anti-inflammatory effects by regulating primary neutrophils through the MAPK signaling pathway.

High-dimensional spectral flow cytometry of activation and phagocytosis by peripheral human polymorphonuclear leukocytes

Polymorphonuclear lymphocytes (PMNs) are terminally differentiated phagocytes with pivotal roles in infection, inflammation, tissue injury, and resolution. PMNs can display a breadth of responses to diverse endogenous and exogenous stimuli, making understanding of these innate immune responders vital yet challenging to achieve. Here, we report a 22-color spectral flow cytometry panel to profile primary human PMNs on population and single cell levels for surface marker expression of activation, degranulation, phagocytosis, migration, chemotaxis, and interaction with fluorescently labeled cargo. We demonstrate the surface protein response of PMNs to phorbol ester stimulation compared to untreated controls in an adherent PMN model with additional analysis of intra- and inter-subject variability. PMNs challenged with the Gram-negative bacterial pathogen Neisseria gonorrhoeae revealed infectious dose-dependent changes in surface marker expression in bulk, population-level analysis. Imaging flow cytometry complemented spectral cytometry, demonstrating that fluorescence signal from labeled bacteria corresponded with bacterial burden on a per-cell basis. Spectral flow cytometry subsequently identified surface markers which varied with direct PMN-bacterium association as well as those which varied in the presence of bacteria but without phagocytosis. This spectral panel protocol highlights best practices for efficient customization and is compatible with downstream approaches such as spectral cell sorting and single-cell RNA-sequencing for applicability to diverse research questions in the field of PMN biology.

Neutrophils in Atopic Dermatitis

Neutrophils have a critical role in inflammation. Recent studies have identified their distinctive presence in certain types of atopic dermatitis (AD), yet their exact function remains unclear. This review aims to compile studies elucidating the role of neutrophils in AD pathophysiology. Proteins released by neutrophils, including myeloperoxidase, elastase, and lipocalin, contribute to pruritus progression in AD. Neutrophilic oxidative stress and the formation of neutrophil extracellular traps may further worsen AD. Elevated neutrophil elastase and high-mobility group box 1 protein expression in AD patients' skin exacerbates epidermal barrier defects. Neutrophil-mast cell interactions in allergic inflammation steer the immunological response toward Th2 imbalance and activate the Th17 pathway, particularly in response to allergens or infections linked to AD. Notably, drugs alleviating pruritic symptoms in AD inhibit neutrophilic inflammation. In conclusion, these findings underscore that neutrophils may be therapeutic targets for AD symptoms, emphasizing their inclusion in AD treatment strategies.

MPO interacts with hRSV particles, contributing to the virucidal effects of NETs against clinical and laboratory hRSV isolates

Human Respiratory syncytial virus (hRSV) mainly affects immunosuppressed patients requiring hospitalization. No specific treatment is financially accessible, and available vaccines do not cover all risk groups. During hRSV infection, there is a robust neutrophilic influx into the airways. hRSV-activated neutrophils release substantial neutrophil extracellular traps (NETs) in lung tissue, comprising DNA, histones, cytosolic, and granular proteins. NETs form mucus buildup in the lungs, compromising respiratory capacity and neutralizing viral particles. Understanding responsible NETs molecules requires improvement. We evaluated NETs interacting with hRSV particles and their contribution to anti-hRSV NET effects. Immunoblotting, immunoprecipitation, and peptide sequencing assays confirmed hRSV binding to a 50-75 kDa NET protein, Myeloperoxidase (MPO). MPO, a microbicide enzyme in NETs, interacts with hRSV, likely at F0 protein (site IV) on the viral surface. Additionally, MPO (32 μM) and NETs (0.4 μg/mL) reduced in vitro replication of clinical (hRSV A and B) and laboratory (Long) hRSV isolates by approximately 30 %, reversible by selective MPO inhibitor (PF-06281355; 48 μM). Thus, MPO contributes to virucidal NET effects on diverse hRSV strains, enhancing comprehension of NETs' role in infection and aiding treatment strategies for respiratory diseases.

The neonatal liver hosts a spontaneously occurring neutrophil population, exhibiting distinct spatial and functional characteristics from adults

The elusive nature of the liver immune system in newborns remains an important challenge, casting a shadow over our understanding of how to effectively treat and prevent diseases in children. Therefore, deeper exploration into the intricacies of neonatal immunology might be crucial for improved pediatric healthcare. Using liver intravital microscopy, we unveiled a significant population of granulocytes in the hepatic parenchyma of fetuses and newborns. Utilizing high-dimensional immunophenotyping, we showed dynamic alterations predominantly in granulocytes during neonatal development. Liver intravital microscopy from birth through adulthood captures real-time dynamics, showing a substantial presence of Ly6G+ cells that persisted significantly up to 2 wk of age. Using time-of flight mass cytometry, we characterized neonatal Ly6G+ cells as neutrophils, confirmed by morphology and immunohistochemistry. Surprisingly, the embryonic liver hosts a distinct population of neutrophils established as early as the second gestational week, challenging conventional notions about their origin. Additionally, we observed that embryonic neutrophils occupy preferentially the extravascular space, indicating their early establishment within the liver. Hepatic neutrophils in embryos and neonates form unique cell clusters, persisting during the initial days of life, while reduced migratory capabilities in neonates are observed, potentially compensating with increased reactive oxygen species release in response to stimuli. Finally, in vivo imaging of acute neutrophil behavior in a newborn mouse, subjected to focal liver necrosis, unveils that neonatal neutrophils exhibit a reduced migratory response. The study provides unprecedented insights into the intricate interplay of neutrophils within the liver, shedding light on their functional and dynamic characteristics during development.

Enhanced insights into the neutrophil-driven immune mechanisms during Mycoplasma pneumoniae infection

Mycoplasma pneumoniae (MP) infections represent a significant component of community-acquired pneumonia, especially in children, invoking a complex neutrophil-mediated immune response, crucial for host defense. This review consolidates current knowledge on the role of neutrophils in MP infection, focusing on their recruitment, migration and activation, as well as the molecular mechanisms underpinning these processes. Significant findings indicate that specific bacterial components, notably CARDS toxin and lipoproteins, intensify neutrophil recruitment via signaling pathways, including the IL-23/IL-17 axis and G-CSF. Furthermore, neutrophils engage in a series of responses, including phagocytosis, degranulation and NETosis, to combat infection effectively. However, dysregulated neutrophil activity can lead to exacerbated lung injury, highlighting the delicate balance required in neutrophil responses. Age and immunodeficiency also emerge as critical factors influencing the severity of MP infections. This review emphasizes the dual role of neutrophils in both defending against and exacerbating MP infections, suggesting that targeted therapeutic strategies could mitigate the adverse effects while enhancing beneficial neutrophil functions.

Neutrophil phenotypes in prolonged labor: Implications for therapeutic strategies

Prolonged labor, defined as labor extending beyond 20 hours for nulliparas and 14 hours for multiparas, poses significant risks to both maternal and neonatal health. The inflammatory response plays a crucial role in the pathophysiology of prolonged labor, with neutrophils being key players in this process. Neutrophils, the most abundant leukocytes, exhibit diverse phenotypes and functions in response to prolonged labor, influencing both the onset and progression of labor through their inflammatory actions. Classical neutrophils (N1) are involved in acute inflammatory responses, aiding in tissue remodeling and labor onset, but their prolonged activation can lead to tissue damage. Regulatory neutrophils (N2), which produce anti-inflammatory cytokines, help resolve inflammation and facilitate labor progression. Low-density granulocytes and aged neutrophils, associated with chronic inflammation and impaired function respectively, contribute to labor complications. The balance among these neutrophil phenotypes is crucial for maintaining a controlled inflammatory response during labor. Therapeutic strategies targeting neutrophil recruitment, NETosis, and cytokine production hold promise for managing prolonged labor. Modulating chemokine pathways, regulating NET formation, and balancing cytokine profiles may reduce inflammation and improve labor outcomes. Further research into the mechanisms of neutrophil regulation and the development of targeted therapies is essential for mitigating the adverse effects of prolonged labor and enhancing maternal and neonatal health.

Distinct neutrophil effector functions in response to different isolates of Leishmania aethiopica

BACKGROUND

In Ethiopia, cutaneous leishmaniasis is mainly caused by Leishmania (L.) aethiopica parasites and presents in three main clinical forms. It is still not clear if the host immune response plays a role in the development of these different presentations. Since neutrophils are likely to be one of the first immune cells present at the site of the sand fly bite, we set up an in vitro model of infection of neutrophils with L. aethiopica and assessed some of the main neutrophil effector functions: association with and internalisation of parasites, apoptosis and ROS production. We used three freshly isolated clinical isolates and one isolate that has been kept in culture for decades.

RESULTS

Our results showed by flow cytometry that all four L. aethiopica isolates had the ability to associate with neutrophils. The three clinical isolates of L. aethiopica associated more efficiently with neutrophils than the long-term cultured L. aethiopica. At 18 h, two distinct populations of neutrophils were identified that associated with L. aethiopica, CD15high and CD15low neutrophils. Confocal microscopy demonstrated that all isolates can be internalised. Our results also showed that all parasites induced apoptosis in L. aethiopica-associated neutrophils. Moreover, our results showed that after 2 h, L. aethiopica-associated neutrophils upregulated their production of ROS, but to a greater extent with the long-term cultured L. aethiopica. After 18 h of incubation, CD15lowparasite+ showed an impaired ability to produce ROS compared to CD15highparasite+.

CONCLUSIONS

Using this in vitro model, our results show that different L. aethiopica parasite isolates, most notably long-term cultured parasites, had differential effects on neutrophil effector functions.

Harnessing Gene Editing Technology for Tumor Microenvironment Modulation: An Emerging Anticancer Strategy

Cancer is a multifaceted disease influenced by both intrinsic cellular traits and extrinsic factors, with the tumor microenvironment (TME) being crucial for cancer progression. To satisfy their high proliferation and aggressiveness, cancer cells always plunder large amounts of nutrients and release various signals to their surroundings, forming a dynamic TME with special metabolic, immune, microbial and physical characteristics. Due to the neglect of interactions between tumor cells and the TME, traditional cancer therapies often struggle with challenges such as drug resistance, low efficacy, and recurrence. Importantly, the development of gene editing technologies, particularly the CRISPR-Cas system, offers promising new strategies for cancer treatment. Combined with nanomaterial strategies, CRISPR-Cas technology exhibits precision, affordability, and user-friendliness with reduced side effects, which holds great promise for profoundly altering the TME at the genetic level, potentially leading to lasting anticancer outcomes. This review will delve into how CRISPR-Cas can be leveraged to manipulate the TME, examining its potential as a transformative anticancer therapy.

Conquering dual challenges: A sialic-modified liposome for targeting activated neutrophils to tackle comorbid lung inflammation and cancer metastasis

In clinical settings, cancer frequently coexists with multi-system diseases. Owing to compromised immune systems, patients with cancer exhibit an increased susceptibility to infections and inflammation. Notably, lung inflammation occurs with high incidence among these patients. Furthermore, the inflammatory milieu within the lungs often accelerates the metastasis of cancer, thereby enhancing mortality rates and posing substantial challenges for clinical management. To date, effective strategies addressing both lung inflammation and cancer concurrently are lacking. In this context, we introduce a novel therapeutic approach involving a sialic acid-lipid derivative (SA-PG10-C18) modified doxorubicin-curcumin co-loaded liposome (DOX/CUR-SAL). This formulation effectively targeted activated neutrophils, which are abundantly present in inflammatory and metastatic lung tissues. DOX/CUR-SAL notably inhibited neutrophil-mediated pro-inflammatory and pro-metastatic processes. Utilizing a newly established mouse model of acute lung injury (ALI) and metastasis comorbidity, DOX/CUR-SAL modulated the lung immune microenvironment and arrested the progression of both inflammation and metastasis, without inducing side effects. The treated animals demonstrated favorable survival conditions, persisting beyond 45 days. This innovative therapeutic strategy offers a novel concept and reference for treating comorbid conditions of tumors and inflammation, thus breaking the clinical impasse where lung inflammation and cancer metastasis have been treated separately.