Neutrophil transendothelial migration: updates and new perspectives

A DNA-based nanorobot for targeting, hitchhiking, and regulating neutrophils to enhance sepsis therapy

Targeted regulation of neutrophils is an effective approach for treating neutrophil-driven inflammatory diseases, but challenges remain in minimizing off-target effects and extending drug half-life. A DNA-based nanorobot was developed to target neutrophils by using an N-acetyl Pro-Gly-Pro (Ac-PGP) peptide to specifically bind to the C-X-C motif of chemokine receptor 2 (CXCR2) on neutrophil membranes. This robot (a tetrahedral framework nucleic acid modified with Ac-PGP, APT) identified and hitchhiked neutrophils to accumulate at inflammatory sites and prolong its half-lives, whilst also was internalized to influence the neutrophil cell cycle and maturation process to regulate oxidative stress, inflammation, migration, and recruitment in both in vivo and in vitro inflammation experiments. Consequently, the tissue damage caused by sepsis was greatly reduced. This novel neutrophil-based nanorobot highlights the high precision of targeting and regulating neutrophils, and presents a potential strategy for treating multiple neutrophil-driven diseases.

STIM1/2 maintain signaling competence at ER-PM contact sites during neutrophil spreading

Neutrophils are highly motile leukocytes that migrate inside tissues to destroy invading pathogens. Ca2+ signals coordinate leukocytes migration, but whether Ca2+ fluxes mediated by Stim proteins at ER-PM contact sites regulate neutrophil actin-based motility is unclear. Here, we show that myeloid-specific Stim1/2 ablation decreases basal cytosolic Ca2+ levels and prevents adhesion-induced Ca2+ elevations in mouse neutrophils, reducing actin fiber formation and impairing spreading. Unexpectedly, more ER-PM contact sites were detected on the actin-poor adhesive membranes of Stim1/2-deficient neutrophils, which had reduced inositol-1,4,5-trisphosphate receptor (IP3R) immunoreactivity on confocal and immunogold micrographs despite preserved IP3R levels on western blots. Remarkably, Stim1/2-deficient neutrophils regained signaling and spreading competence in Ca2+-rich solutions and were recruited more effectively in mouse inflamed cremaster muscles in vivo. Our findings indicate that Stim1/2 preserve IP3R functionality in neutrophils, generating adhesion-dependent Ca2+ signals that control actin dynamics during neutrophil spreading. Stim proteins thus maintain IP3R signaling competence at adhesive membranes, enabling Ca2+-dependent actin remodeling during spreading in mouse neutrophils.

Neutrophil-Mediated Tumor Discrimination Biomimetic Nanodevice for Precise Tumor Eradication and Metastasis Cascade Perturbing

The deficient discrimination of tumor cells, limited accumulation of therapeutic agents in tumor foci, and undesirable tumor metastasis result in compromised therapeutic efficacy in antitumor therapy. Neutrophils, the most abundant circulating leukocytes, are key players in tumor progression and have a high affinity to tumors. Herein, a biomimetic tumor discrimination nanodevice (NL-FSB) is developed by harboring a pH-sensitive Fenton agent (FSB) in an activated neutrophil membrane-incorporated liposome for tumor-specific ablation. Inheriting the biointerfacing properties of neutrophils, NL-FSB is endowed with high affinity to tumors. On one hand, NL-FSB can be recruited to acidic tumor sites mediated by chemotaxis attraction and selectively generate reactive oxygen species via amplified Fenton chemical reaction for specific tumor eradication. On the other hand, the biomimetic NL-FSB can also target and bind tumor vascular endothelium or circulating tumor cells (CTCs) in circulation, executing pseudo escort to perturb CTC-neutrophil cluster formation and tumor metastasis cascade. Unprecedentedly, the neutrophil-mediated nanoagent can effectively inhibit the already-formed tumor and prevent tumor metastasis with high specificity. Our study represents a promising yet simple strategy for tumor-specific killing and metastasis cascade blockage via a nanobioengineering functionalization strategy.

PRIM1 enhances colorectal cancer liver metastasis via promoting neutrophil recruitment and formation of neutrophil extracellular trap

Despite advances in treatment, liver metastasis remains the predominant pattern of distant spread for colorectal cancer (CRC) and a major cause of cancer-related mortality. DNA Primase Subunit 1 (PRIM1) has been reported to play important roles in cancer progression. This study investigated the role of PRIM1 in CRC liver metastasis, focusing on its influence on neutrophil recruitment and the formation of neutrophil extracellular traps (NETs). In this study, PRIM1 was upregulated in liver metastasis tumor tissues. CCK-8 and Transwell assays showed that the proliferation, migration and invasion of CRC cells were promoted with the ablation of PRIM1 and inhibited with PRIM1 overexpression. For in vivo investigation, we observed that PRIM1 ablation reduced the number and size of metastasis nodules of MC38 cells. Importantly, PRIM1 depletion obviously reduced the percentage of Ly6G+ neutrophils in liver. In contrast, overexpression of PRIM1 reversed these effects. Besides, depletion of neutrophils by anti-Ly6G antibody in mice notably attenuated liver metastasis burden induced by the upregulation of PRIM1. Western blot and immunohistochemistry assays revealed that three chemokines CXCL8, C-GSF and CXCL2 were confirmed to be upregulated with PRIM1 overexpression. Furthermore, PRIM1 overexpression reduced the formation of NETs. These results suggested that PRIM1 could facilitate the liver metastasis of CRC via recruiting neutrophils and NET formation. In conclusion, our novel findings highlighted the important role of PRIM1 in neutrophil recruitment and CRC metastasis and provided new perspectives and potential targets for future research and treatment for CRC.

S2Map: a novel computational platform for identifying secretio-types through cell secretion-signal map

Motivation

Cell communication is predominantly governed by secreted proteins, whose diverse secretion patterns often signify underlying physiological irregularities. Understanding these secreted signals at an individual cell level is crucial for gaining insights into regulatory mechanisms involving various molecular agents. To elucidate the array of cell secretion signals, which encompass different types of biomolecular secretion cues from individual immune cells, we introduce the secretion-signal map (S2Map).

Results

S2Map is an online interactive analytical platform designed to explore and interpret distinct cell secretion-signal patterns visually. It incorporates two innovative qualitative metrics, the signal inequality index and the signal coverage index, which are exquisitely sensitive in measuring dissymmetry and diffusion of signals in temporal data. S2Map's innovation lies in its depiction of signals through time-series analysis with multi-layer visualization. We tested the SII and SCI performance in distinguishing the simulated signal diffusion models. S2Map hosts a repository for the single-cell's secretion-signal data for exploring cell secretio-types, a new cell phenotyping based on the cell secretion signal pattern. We anticipate that S2Map will be a powerful tool to delve into the complexities of physiological systems, providing insights into the regulation of protein production, such as cytokines at the remarkable resolution of single cells.

Availability and implementation

The S2Map server is publicly accessible via https://au-s2map.streamlit.app/.

Neutrophil plasticity in liver diseases

The liver has critical digestive, metabolic, and immunosurveillance roles, which get disrupted during liver diseases such as viral hepatitis, fatty liver disease, and hepatocellular carcinoma. While previous research on the pathological development of these diseases has focused on liver-resident immune populations, such as Kupffer cells, infiltrating immune cells responding to pathogens and disease also play crucial roles. Neutrophils are one such key population contributing to hepatic inflammation and disease progression. Belonging to the initial waves of immune response to threats, neutrophils suppress bacterial and viral spread during acute infections and have homeostasis-restoring functions, whereas during chronic insults, they display their plastic nature by responding to the inflammatory environment and develop new phenotypes alongside longer life spans. This review summarizes the diversity in neutrophil function and subpopulations present at steady state, during liver disease, and during liver cancer.

Aberrant expansion of CD177+ neutrophils promotes endothelial dysfunction in systemic lupus erythematosus via neutrophil extracellular traps

OBJECTIVE

Aberrant neutrophil activation is implicated in the pathogenesis of systemic lupus erythematosus (SLE) and its related comorbidities. We found that CD177 was one of the most highly up-regulated genes at the transcriptional level in purified neutrophils from SLE patients. In this study, we aimed to explore the role of CD177+ neutrophils in the pathogenesis of SLE.

METHODS

Expression of CD177 was analyzed by neutrophil transcriptome and flow cytometry. CD177+ neutrophils and CD177-neutrophils were isolated to determine the role of neutrophils-derived NETs in endothelium dysfunction. Wild type and CD177-/- murine model of lupus were analyzed for organ involvement, endothelium-dependent vasorelaxation, serum autoantibodies, and innate and adaptive immune responses in an imiquimod (IMQ)-induced lupus model.

RESULTS

CD177MFI-hi neutrophils and CD177MFI-hi low-density granulocytes (LDGs) were expanded in active SLE, which were weakly but significantly associated with disease activity. CD177+neutrophils displayed enhanced production of reactive oxygen species (ROS) and NETs, which impaired the murine aortic endothelium-dependent vasorelaxation and induced endothelial cell apoptosis. Moreover, CD177-/- mice exposed to IMQ showed alleviated splenomegaly, endothelium-dependent vasorelaxation, and renal immune complex deposition.

CONCLUSIONS

Our findings indicated that CD177 MFI-hi may serve as a novel biomarker for monitoring disease activity in SLE. Further, CD177+ neutrophils may play a vasculopathic role in cardiovascular disease (CVD) via NETs formation, suggesting that specific targeting CD177+ neutrophil subset may have therapeutic effect in SLE but reducing the levels of NETs-prone neutrophils.

The Interplay Between Immunity, Inflammation and Endothelial Dysfunction

The endothelium is pivotal in multiple physiological processes, such as maintaining vascular homeostasis, metabolism, platelet function, and oxidative stress. Emerging evidence in the past decade highlighted the immunomodulatory function of endothelium, serving as a link between innate, adaptive immunity and inflammation. This review examines the regulation of the immune-inflammatory axis by the endothelium, discusses physiological immune functions, and explores pathophysiological processes leading to endothelial dysfunction in various metabolic disturbances, including hyperglycemia, obesity, hypertension, and dyslipidaemia. The final section focuses on the novel, repurposed, and emerging therapeutic targets that address the immune-inflammatory axis in endothelial dysfunction.

Dysregulation of neutrophil in sepsis: recent insights and advances

Sepsis remains the leading cause of death in intensive care units. Despite newer antimicrobial and supportive therapies, specific treatments are still lacking. Neutrophils are pivotal components of the effector phase of the host immune defense against pathogens and play a crucial role in the control of infections under normal circumstances. In addition to its anti-infective effects, the dysregulation and overactivation of neutrophils may lead to severe inflammation or tissue damage and are potential mechanisms for poor prognosis in sepsis. This review focuses on recent advancements in the understanding of the functional status of neutrophils across various pathological stages of sepsis to explore the mechanisms by which neutrophils participate in sepsis progression and provide insights for the treatment of sepsis by targeting neutrophils.

Risk beyond neutropenia: insights into neutrophil migration from newly diagnosed AML until late after allogeneic stem cell transplantation

Quantification of neutrophil counts is the most relevant assessment of cellular immunity in clinical practice. Patients with neutropenia are considered at risk and are categorized according to its severity. The incidence of febrile neutropenia varies, but patients with acute myeloid leukemia are traditionally considered at high risk, especially following myelotoxic treatments. To provide additional functional parameters, we investigated the ex vivo migration properties and morphology of neutrophils in 10 patients with acute myeloid leukemia using single-cell video-microscopy and discovered, in addition to neutropenia, highly pathological neutrophil migration patterns and polarization defects in patients with untreated acute myeloid leukemia. Neutrophil speed was the most sensitive parameter and significantly lower at leukemia diagnosis (9.067 vs 15.810 µm/min, P = 0.0025) compared to healthy controls (n = 46). Hematological remission was associated with improved neutrophil migration profiles, but these ultimately normalized only after hematopoietic cell transplantation. Five patients were followed up for long-term effects of hematopoietic cell transplantation for up to 24 mo. This is the first longitudinal ex vivo neutrophil migration study in patients with acute myeloid leukemia, followed by allogeneic hematopoietic cell transplantation. It identified functional neutrophil impairments beyond routine quantitative assessments, adding to the well-known quantitative impairment of neutropenia. HCT can reestablish functional neutrophils with healthy migration profiles in these patients.

Neutrophils, Fast and Strong 2.0: Heterogeneity of Neutrophil Parameters in Health and in Disease

Neutrophils are very important cells of the immune system, and every year, new nuances of their functional activity in the body and participation in various pathological processes are discovered [...].

RHO subfamily of small GTPases in the development and function of hematopoietic cells

RHOA, RHOB, and RHOC comprise a subfamily of RHO GTPase proteins famed for controlling cytoskeletal dynamics. RHO proteins operate downstream of multiple signals emerging from the microenvironment, leading to diverse cell responses, such as proliferation, adhesion, and migration. Therefore, RHO signaling has been centrally placed in the regulation of blood cells. Despite their high homology, unique roles of RHOA, RHOB, and RHOC have been described in hematopoietic cells. In this article, we overview the contribution of RHO proteins in the development and function of each blood cell lineage. Additionally, we highlight the aberrations of the RHO signaling pathways found in hematological malignancies, providing clues for the identification of new therapeutic targets.

Basement membranes' role in immune cell recruitment to the central nervous system

Basement membranes form part of the extracellular matrix (ECM), which is the structural basis for all tissue. Basement membranes are cell-adherent sheets found between cells and vascular endothelia, including those of the central nervous system (CNS). There is exceptional regional specialisation of these structures, both in tissue organisation and regulation of tissue-specific cellular processes. Due to their location, basement membranes perform a key role in immune cell trafficking and therefore are important in inflammatory processes causing or resulting from CNS disease and injury. This review will describe basement membranes in detail, with special focus on the brain. We will cover how genetic changes drive brain pathology, describe basement membranes' role in immune cell recruitment and how they respond to various brain diseases. Understanding how basement membranes form the junction between the immune and central nervous systems will be a major advance in understanding brain disease.

Neutrophil diversity and function in health and disease

Neutrophils, the most abundant type of granulocyte, are widely recognized as one of the pivotal contributors to the acute inflammatory response. Initially, neutrophils were considered the mobile infantry of the innate immune system, tasked with the immediate response to invading pathogens. However, recent studies have demonstrated that neutrophils are versatile cells, capable of regulating various biological processes and impacting both human health and disease. Cytokines and other active mediators regulate the functional activity of neutrophils by activating multiple receptors on these cells, thereby initiating downstream signal transduction pathways. Dysfunctions in neutrophils and disruptions in neutrophil homeostasis have been implicated in the pathogenesis of numerous diseases, including cancer and inflammatory disorders, often due to aberrant intracellular signaling. This review provides a comprehensive synthesis of neutrophil biological functions, integrating recent advancements in this field. Moreover, it examines the biological roles of receptors on neutrophils and downstream signaling pathways involved in the regulation of neutrophil activity. The pathophysiology of neutrophils in numerous human diseases and emerging therapeutic approaches targeting them are also elaborated. This review also addresses the current limitations within the field of neutrophil research, highlighting critical gaps in knowledge that warrant further investigation. In summary, this review seeks to establish a comprehensive and multidimensional model of neutrophil regulation, providing new perspectives for potential clinical applications and further research.

ANRIL's Epigenetic Regulation and Its Implications for Cardiovascular Disorders

Cardiovascular disorders (CVDs) are a major global health concern, but their underlying molecular mechanisms are not fully understood. Recent research highlights the role of long noncoding RNAs (lncRNAs), particularly ANRIL, in cardiovascular development and disease. ANRIL, located in the human genome's 9p21 region, significantly regulates cardiovascular pathogenesis. It controls nearby tumor suppressor genes CDKN2A/B through epigenetic pathways, influencing cell growth and senescence. ANRIL interacts with epigenetic modifiers, leading to altered histone modifications and gene expression changes. It also acts as a transcriptional regulator, impacting key genes in CVD development. ANRIL's involvement in cardiovascular epigenetic regulation suggests potential therapeutic strategies. Manipulating ANRIL and its associated epigenetic modifiers could offer new approaches to managing CVDs and preventing their progression. Dysregulation of ANRIL has been linked to various cardiovascular conditions, including coronary artery disease, atherosclerosis, ischemic stroke, and myocardial infarction. This abstract provides insights from recent research, emphasizing ANRIL's significance in the epigenetic landscape of cardiovascular disorders. By shedding light on ANRIL's role in cellular processes and disease development, the abstract highlights its potential as a therapeutic target for addressing CVDs.

The Gastroprotective Effect of Sicyos angulatus Against Hydrochloric Acid/Ethanol-Induced Acute Gastritis and Gastric Ulcer in Mice

Gastritis and gastric ulcers are common gastric diseases that are caused by infection, drugs, alcohol consumption, or stress. These conditions lead to increased inflammatory cytokines and recruitment of leukocytes, which damage the stomach mucosa and exacerbate disease severity. Sicyos angulatus (SA), an annual vine in the Cucurbitaceae family, is known to have an anti-inflammatory effect, but its efficacy for preventing gastritis and gastric ulcers has not yet been evaluated. In the present study, we investigated the gastroprotective effect of SA using a hydrochloric acid/ethanol-induced gastric mucosal injury mouse model and lipopolysaccharide (LPS)-stimulated KATO III cells. Macroscopic analysis revealed a reduction in gastric ulcer area. Similarly, histopathological analysis showed a dose-dependent decrease in gastric mucosal injury, with significant improvement at 750 mg/kg of SA treatment. Gene expressions of inflammatory cytokines, chemokines, and adhesion molecule were reduced in the SA-administered group. Immunohistochemical staining indicated that SA significantly decreased neutrophil infiltration in the lamina propria and epithelium of the stomach. Kaempferol, a major bioactive flavonoid of SA, also improved gastric injury by reducing macroscopic and microscopic lesions, inflammatory mediator gene expression, and neutrophil infiltration. Furthermore, both SA and kaempferol downregulated LPS-mediated increases in inflammatory cytokines and chemokines following inhibition of p38 and c-Jun N-terminal kinase (JNK) phosphorylation in KATO III cells. These results suggest that SA can ameliorate gastric mucosal injury by inhibiting the recruitment of inflammatory cells, particularly neutrophils, and by suppressing p38 and JNK phosphorylation.

A key regulator of tumor-associated neutrophils: the CXCR2 chemokine receptor

In recent years, with the advance of research, the role of tumor-associated neutrophils (TANs) in tumors has become a research hotspot. As important effector cells in the innate immune system, neutrophils play a key role in the immune and inflammatory responses of the body. As the first line of defense against bacterial and fungal infections, neutrophils have the ability to kill invading pathogens. In the pathological state of malignant tumors, the phenotype of neutrophils is altered and has an important regulatory function in tumor development. The C-X-C motif chemokine receptor 2(CXCR2) is a key molecule that mediates the migration and aggregation signaling pathway of immune cells, especially neutrophils. This review focuses on the regulation of CXCR2 on TANs in the process of tumorigenesis and development, and emphasizes the application significance of CXCR2 inhibitors in blocking the migration of TANs to tumors.

The diverse roles of neutrophils from protection to pathogenesis

Neutrophil granulocytes are the most abundant leukocytes in the blood and constitute a critical arm of innate immunity. They are generated in the bone marrow, and under homeostatic conditions enter the bloodstream to patrol tissues and scout for potential pathogens that they quickly destroy through phagocytosis, intracellular degradation, release of granules and formation of extracellular traps. Thus, neutrophils are important effector cells involved in antibacterial defense. However, neutrophils can also be pathogenic. Emerging data suggest they have critical functions related to tissue repair and fibrosis. Moreover, similarly to other innate immune cells, neutrophil cell states are affected by their microenvironment. Notably, this includes tumors that co-opt neutrophils. Neutrophils can undergo transcriptional and epigenetic reprogramming, thus causing or modulating inflammation and injury. It is also possible that distinct neutrophil subsets are generated with designated functions in the bone marrow. Understanding neutrophil plasticity and alternative cell states will help resolve their contradictive roles. This Review summarizes the most recent key findings surrounding protective versus pathogenic functions of neutrophils; elaborating on phenotype-specific subsets of neutrophils and their involvement in homeostasis and disease.

Deciphering infectious uveitis etiology: Immune cell profiling in keratic precipitates using in vivo confocal microscopy

Purpose

To elucidate the etiology of infectious uveitis through the comprehensive analysis of keratic precipitates (KPs) using in vivo confocal microscopy (IVCM).

Design

Cross-sectional, observational case series.

Methods

This single-center, cross-sectional study was conducted at a tertiary care eye hospital from January 2021 to October 2023. It involved a detailed ophthalmologic evaluation of all subjects and included a total of 46 eyes from 36 subjects who were diagnosed with infectious uveitis. IVCM, specifically utilizing the HRT II Rostock corneal module, was employed to study the biomicroscopic morphology of KPs. The categorization of KPs was based on cell size, morphology, and reflection.

Results

Cells of KPs were assessed for size, morphology, and reflection through in vivo confocal microscopy. Patients, ranging in age from 13 to 80 years (median 51 years), exhibited diverse morphologic forms of KPs. Neutrophil-dominated KPs with uniform size were predominantly observed in bacterial and fungal endophthalmitis cases (19/19, 100 %), accompanied by small numbers of mononuclear-macrophages in three eyes (3/19, 15.8 %). Viral uveitis cases displayed a broader array of immune cell types, including characteristic striated or dendritic cells in all eyes (27/27, 100 %). Lymphocytes were commonly present (24/27, 88.9 %), forming clusters in sixteen eyes and dispersed in the corneal endothelium below the midline in eight eyes. Neutrophil infiltration was notable in three cytomegalovirus-infected eyes (3/27, 11.1 %). A marked increase in sub-basal corneal epithelial Langhans cells was associated with viral uveitis.

Conclusions

Neutrophil-dominated KPs strongly indicate endogenous bacterial or fungal endophthalmitis, while the presence of dendritic cells and lymphocytes in KPs is suggestive of viral uveitis. In vivo confocal microscopy emerges as a crucial tool for differentiating the etiologic diagnosis of infectious uveitis.

Synergistic potentiation of the anti-metastatic effect of a Ginseng-Salvia miltiorrhiza herbal pair and its biological ingredients via the suppression of CD62E-dependent neutrophil infiltration and NETformation

INTRODUCTION

The combination of the roots of ginseng and Salvia miltiorrhiza is an effective approach for treating metastatic cancer in patients with Qi stagnation and blood stasis patterns. However, the molecular mechanism underlying the combined use of ginseng and Salvia miltiorrhiza is unknown.

OBJECTIVES

This study unveils the pharmacological foundation of ginseng and Salvia miltiorrhiza by examining the involvement of neutrophils in the critical process of tumor hematogenous metastasis. Additionally, by employing a reverse pharmacology research model (effect-target-constituent), potential potent components were screened, and the dominant component formulations were determined.

METHODS

An experimental lung metastatic model was constructed to compare the antitumor effects of ginseng and Salvia miltiorrhiza. RNA sequencing was employed to identify pivotal biological events and key targets, while the detection of CD62E expression and neutrophil extracellular traps (NETs) release was used to screen for effective substances in ginseng and Salvia miltiorrhiza. In addition, a comprehensive array of in vitro and in vivo experiments was conducted to explore the underlying mechanisms and therapeutic significance.

RESULTS

Compared with single-herb use, the use of ginseng or Salvia miltiorrhiza significantly reduced tumor metastasis, which was accompanied by reduced neutrophil infiltration into the lungs. Cryptotanshinone (CPT), an active constituent of Salvia miltiorrhiza, can inhibit neutrophil adhesion and recruitment to lung tissue by downregulating the expression of E-selectin (CD62E) in endothelial cells. Moreover, the ginseng-derived ginsenoside Rg1 mitigated the formation of NETs in lung tissues and reversed the protumor effects of NETs. We further explored the efficacy of combination therapy with Rg1 and CPT, which also reduced tumor metastasis in vivo.

CONCLUSION

Ginseng and Salvia miltiorrhiza exhibited a mutual potentiation of the anti-metastatic effect by suppressing both early and late stages of neutrophil-initiated metastasis cascade. Rg1 and CPT represent the synergistic ingredients from ginseng and Salvia miltiorrhiza, respectively.

G-CSFR-induced leukocyte transendothelial migration during the inflammatory response is regulated by the ICAM1-PKCa axis: based on multiomics integration analysis

As an indispensable inflammatory mediator during sepsis, granulocyte colony-stimulating factor (G-CSF) facilitates neutrophil production by activating G-CSFR. However, little is known about the role of intracellular downstream signalling pathways in the induction of inflammation. To explore the functions of molecules in regulating G-CSFR signalling, RNA sequencing and integrated proteomic and phosphoproteomic analyses were conducted to predict the differentially expressed molecules in modulating the inflammatory response after G-CSFR expression was either up- or downregulated, in addition to the confirmation of their biological function by diverse experimental methods. In the integrated bioinformatic analysis, 3190 differentially expressed genes (DEGs) and 1559 differentially expressed proteins (DEPs) were identified in multiple-group comparisons (p < 0.05, FC >  ± 1.5) using enrichment analyses, as well as those classic pathways such as the TNF, NFkappaB, IL-17, and TLR signalling pathways. Among them, 201 proteins, especillay intercellular cell adhesion molecule-1 (ICAM1) and PKCa, were identified as potential molecules involved in inflammation according to the protein-protein interaction (PPI) analysis, and the leukocyte transendothelial migration (TEM) pathway was attributed to the intervention of G-CSFR. Compared with the control and TNF-a treatment, the G-CSFR (G-CSFROE)-overexpressing led to an obvious increase in the number of leukocytes with the TEM phenotype. Mechanically, the expression of ICAM1 and PKCa was significantly up- and downregulated by G-CSFROE, which directly led to increased TEM; moreover, PKCa expression was negatively regulated by ICAM1 expression, leading to aberrant leukocyte TEM. Altogether, the ICAM1‒PKCa axis was found a meaningful target in the leukocyte TEM induced by G-CSFR upregulation.

Neutrophils under the microscope: neutrophil dynamics in infection, inflammation, and cancer revealed using intravital imaging

Neutrophils rapidly respond to inflammation resulting from infection, injury, and cancer. Intravital microscopy (IVM) has significantly advanced our understanding of neutrophil behavior, enabling real-time visualization of their migration, interactions with pathogens, and coordination of immune responses. This review delves into the insights provided by IVM studies on neutrophil dynamics in various inflammatory contexts. We also examine the dual role of neutrophils in tumor microenvironments, where they can either facilitate or hinder cancer progression. Finally, we highlight how computational modeling techniques, especially agent-based modeling, complement experimental data by elucidating neutrophil kinetics at the level of individual cells as well as their collective behavior. Understanding the role of neutrophils in health and disease is essential for developing new strategies for combating infection, inflammation and cancer.

Factors affecting neutrophil functions during sepsis: human microbiome and epigenetics

Sepsis is a severe disease that occurs when the body's immune system reacts excessively to infection. The body's response, which includes an intense antibacterial reaction, can damage its tissues and organs. Neutrophils are the major components of white blood cells in circulation, play a vital role in innate immunity while fighting against infections, and are considered a feature determining sepsis classification. There is a plethora of basic research detailing neutrophil functioning, among which, the study of neutrophil extracellular traps is providing novel insights into mechanisms and treatments of sepsis. This review explores their functions, dysfunctions, and influences in the context of sepsis. The interplay between neutrophils and the human microbiome and the impact of DNA methylation on neutrophil function in sepsis are crucial areas of study. The interaction between neutrophils and the human microbiome is complex, particularly in the context of sepsis, where dysbiosis may occur. We highlight the importance of deciphering neutrophils' functional alterations and their epigenetic features in sepsis because it is critical for defining sepsis endotypes and opening up the possibility for novel diagnostic methods and therapy. Specifically, epigenetic signatures are pivotal since they will provide a novel implication for a sepsis diagnostic method when used in combination with the cell-free DNA. Research is exploring how specific patterns of DNA methylation in neutrophils, detectable in cell-free DNA, could serve as biomarkers for the early detection of sepsis.

Alveolar macrophage function is impaired following inhalation of berry e-cigarette vapor

In the lower respiratory tract, the alveolar spaces are divided from the bloodstream and the external environment by only a few microns of interstitial tissue. Alveolar macrophages (AMs) defend this delicate mucosal surface from invading infections by regularly patrolling the site. AMs have three behavior modalities to achieve this goal: extending cell protrusions to probe and sample surrounding areas, squeezing the whole cell body between alveoli, and patrolling by moving the cell body around each alveolus. In this study, we found Rho GTPase, cell division control protein 42 (CDC42) expression significantly decreased after berry-flavored e-cigarette (e-cig) exposure. This shifted AM behavior from squeezing to probing. Changes in AM behavior led to a reduction in the clearance of inhaled bacteria, Pseudomonas aeruginosa. These findings shed light on pathways involved in AM migration and highlight the harmful impact of e-cig vaping on AM function.

Micro/Nanomotor-Driven Intelligent Targeted Delivery Systems: Dynamics Sources and Frontier Applications

Micro/nanomotors represent a promising class of drug delivery carriers capable of converting surrounding chemical or external energy into mechanical power, enabling autonomous movement. Their distinct autonomous propulsive force distinguishes them from other carriers, offering significant potential for enhancing drug penetration across cellular and tissue barriers. A comprehensive understanding of micro/nanomotor dynamics with various power sources is crucial to facilitate their transition from proof-of-concept to clinical application. In this review, micro/nanomotors are categorized into three classes based on their energy sources: endogenously stimulated, exogenously stimulated, and live cell-driven. The review summarizes the mechanisms governing micro/nanomotor movements under these energy sources and explores factors influencing autonomous motion. Furthermore, it discusses methods for controlling micro/nanomotor movement, encompassing aspects related to their structure, composition, and environmental factors. The remarkable propulsive force exhibited by micro/nanomotors makes them valuable for significant biomedical applications, including tumor therapy, bio-detection, bacterial infection therapy, inflammation therapy, gastrointestinal disease therapy, and environmental remediation. Finally, the review addresses the challenges and prospects for the application of micro/nanomotors. Overall, this review emphasizes the transformative potential of micro/nanomotors in overcoming biological barriers and enhancing therapeutic efficacy, highlighting their promising clinical applications across various biomedical fields.

Endothelial Cell-Derived Extracellular Vesicles Promote Aberrant Neutrophil Trafficking and Subsequent Remote Lung Injury

The development of acute respiratory distress syndrome (ARDS) in sepsis is associated with substantial morbidity and mortality. However, the molecular pathogenesis underlying sepsis-induced ARDS remains elusive. Neutrophil heterogeneity and dysfunction contribute to uncontrolled inflammation in patients with ARDS. A specific subset of neutrophils undergoing reverse transendothelial migration (rTEM), which is characterized by an activated phenotype, is implicated in the systemic dissemination of inflammation. Using single-cell RNA sequencing (scRNA-seq), it identified functionally activated neutrophils exhibiting the rTEM phenotype in the lung of a sepsis mouse model using cecal ligation and puncture. The prevalence of neutrophils with the rTEM phenotype is elevated in the blood of patients with sepsis-associated ARDS and is positively correlated with disease severity. Mechanically, scRNA-seq and proteomic analys revealed that inflamed endothelial cell (EC) released extracellular vesicles (EVs) enriched in karyopherin subunit beta-1 (KPNB1), promoting abluminal-to-luminal neutrophil rTEM. Additionally, EC-derived EVs are elevated and positively correlated with the proportion of rTEM neutrophils in clinical sepsis. Collectively, EC-derived EV is identified as a critical regulator of neutrophil rTEM, providing insights into the contribution of rTEM neutrophils to sepsis-associated lung injury.

[Pterocarya hupehensis Skan total flavones ameliorate rheumatoid arthritis in rats by suppressing formation of neutrophil extracellular traps]

OBJECTIVE

To investigate the therapeutic mechanism of Pterocarya hupehensis Skan total flavonoids (PHSTF) for rheumatoid arthritis (RA).

METHODS

Twenty-five male SD rats were randomly divided into normal control group, RA model group, PHSTF treatment (45 and 90 mg/kg) groups, and Tripterygium glycosides (TPG) tablet (10 mg/kg) group (n=5). Except for those in the normal control group, all the rats were subjected to collagen-induced arthritis (CIA) modeling using a secondary immunization method, after which PHSTF and TPG were administered via gavage once daily for 4 weeks. After the treatments, serum levels of TNF-α and IL-1β were measured using ELISA, and ankle joint pathologies were assessed with HE staining; the expression of citrullinated histone H3 (Cit-H3), a neutrophil extracellular trap (NET) marker, in the ankle joints was evaluated with immunohistochemistry. In primary cultures of rat peripheral blood neutrophils stimulated with phorbol ester (PMA), the effects of PHSTF (100 and 200 μg/mL) on the expressions of Cit-H3, peptidylarginine deiminase 4 (PADI4), neutrophil elastase (NE), and myeloperoxidase (MPO) were examined with Western blotting; immunofluorescence assay was used to observe Cit-H3 expression and NET formation in the cells.

RESULTS

In the CIA rat models, PHSTF significantly alleviated ankle swelling, decreased serum levels of TNF-α and IL-1β, improved histopathological changes in the ankle joints, and reduced Cit-H3 expression in both the serum and ankle joint cartilage. In the isolated rat neutrophils, PHSTF showed no significant effect on cell viability but strongly inhibited PMA-induced NET release.

CONCLUSION

PHSTF can alleviate RA by inhibiting the formation of NETs.

Microfluidic device reveals new insights into impairment of neutrophil transmigration in patients with sepsis

Neutrophils need to migrate through tight tissue spaces to eliminate pathogens, but their movement is often hindered by their large and stiff nuclei. Neutrophil migration is impaired in sepsis patients, but it is unclear whether this defect is related to the deformability of their nuclei. Herein, we designed microfluidic devices with micron-scale narrow slits to simulate biological barriers. This setup allowed us to observe and record neutrophil movement and nuclear deformation in real-time. We also developed a method for morphological analysis to quantify nucleus deformation in numerous individual cells. Our studies showed that neutrophils from healthy individuals could adjust their nuclear shape to squeeze through these constrictions, whereas those from sepsis patients demonstrated less flexibility. Neutrophils with rigid nuclei struggled to pass through narrow gaps and were more likely to rupture under pressure. These findings suggest that the migration defects of neutrophils observed in sepsis may be attributed to the inability of neutrophils to deform their nuclei, highlighting the crucial role of microfluidic technologies in offering new insights into migration defects under pathological conditions.

CC chemokines Modulate Immune responses in Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension (PH) represents a progressive condition characterized by the remodeling of pulmonary arteries, ultimately culminating in right heart failure and increased mortality rates. Substantial evidence has elucidated the pivotal role of perivascular inflammatory factors and immune dysregulation in the pathogenesis of PH. Chemokines, a class of small secreted proteins, exert precise control over immune cell recruitment and functionality, particularly with respect to their migration to sites of inflammation. Consequently, chemokines emerge as critical drivers facilitating immune cell infiltration into the pulmonary tissue during inflammatory responses. This review comprehensively examines the significant contributions of CC chemokines in the maintenance of immune cell homeostasis and their pivotal role in regulating inflammatory responses. The central focus of this discussion is directed towards elucidating the precise immunoregulatory actions of CC chemokines concerning various immune cell types, including neutrophils, monocytes, macrophages, lymphocytes, dendritic cells, mast cells, eosinophils, and basophils, particularly in the context of pH processes. Furthermore, this paper delves into an exploration of the underlying pathogenic mechanisms that underpin the development of PH. Specifically, it investigates processes such as cellular pyroptosis, examines the intricate crosstalk between bone morphogenetic protein receptor type 2 (BMPR2) mutations and the immune response, and sheds light on key signaling pathways involved in the inflammatory response. These aspects are deemed critical in enhancing our understanding of the complex pathophysiology of PH. Moreover, this review provides a comprehensive synthesis of findings from experimental investigations targeting immune cells and CC chemokines.

AIM OF REVIEW

In summary, the inquiry into the inflammatory responses mediated by CC chemokines and their corresponding receptors, and their potential in modulating immune reactions, holds promise as a prospective avenue for addressing PH. The potential inhibition of CC chemokines and their receptors stands as a viable strategy to attenuate the inflammatory cascade and ameliorate the pathological manifestations of PH. Nonetheless, it is essential to acknowledge the current state of clinical trials and the ensuing progress, which regrettably appears to be less than encouraging. Substantial hurdles exist in the successful translation of research findings into clinical applications. The intention is that such emphasis could potentially foster the advancement of potent therapeutic agents presently in the process of clinical evaluation. This, in turn, may further bolster the potential for effective management of PH.

In vitro and ex vivo models of microbial keratitis: Present and future

Microbial keratitis (MK) is an infection of the cornea, caused by bacteria, fungi, parasites, or viruses. MK leads to significant morbidity, being the fifth leading cause of blindness worldwide. There is an urgent requirement to better understand pathogenesis in order to develop novel diagnostic and therapeutic approaches to improve patient outcomes. Many in vitro, ex vivo and in vivo MK models have been developed and implemented to meet this aim. Here, we present current in vitro and ex vivo MK model systems, examining their varied design, outputs, reporting standards, and strengths and limitations. Major limitations include their relative simplicity and the perceived inability to study the immune response in these MK models, an aspect widely accepted to play a significant role in MK pathogenesis. Consequently, there remains a dependence on in vivo models to study this aspect of MK. However, looking to the future, we draw from the broader field of corneal disease modelling, which utilises, for example, three-dimensional co-culture models and dynamic environments observed in bioreactors and organ-on-a-chip scenarios. These remain unexplored in MK research, but incorporation of these approaches will offer further advances in the field of MK corneal modelling, in particular with the focus of incorporation of immune components which we anticipate will better recapitulate pathogenesis and yield novel findings, therefore contributing to the enhancement of MK outcomes.

Pathogenesis and interaction of neutrophils and extracellular vesicles in noncancer liver diseases

Liver disease ranks as the eleventh leading cause of mortality, leading to approximately 2 million deaths annually worldwide. Neutrophils are a type of immune cell that are abundant in peripheral blood and play a vital role in innate immunity by quickly reaching the site of liver injury. They exert their influence on liver diseases through autocrine, paracrine, and immunomodulatory mechanisms. Extracellular vesicles, phospholipid bilayer vesicles, transport a variety of substances, such as proteins, nucleic acids, lipids, and pathogenic factors, for intercellular communication. They regulate cell communication and perform their functions by delivering biological information. Current research has revealed the involvement of the interaction between neutrophils and extracellular vesicles in the pathogenesis of liver disease. Moreover, more research has focused on targeting neutrophils as a therapeutic strategy to attenuate disease progression. Therefore, this article summarizes the roles of neutrophils, extracellular vesicles, and their interactions in noncancerous liver diseases.

Collagen concentration regulates neutrophil extravasation and migration in response to infection in an endothelium dependent manner

Introduction

As the body's first line of defense against disease and infection, neutrophils must efficiently navigate to sites of inflammation; however, neutrophil dysregulation contributes to the pathogenesis of numerous diseases that leave people susceptible to infections. Many of these diseases are also associated with changes to the protein composition of the extracellular matrix. While it is known that neutrophils and endothelial cells, which play a key role in neutrophil activation, are sensitive to the mechanical and structural properties of the extracellular matrix, our understanding of how protein composition in the matrix affects the neutrophil response to infection is incomplete.

Methods

To investigate the effects of extracellular matrix composition on the neutrophil response to infection, we used an infection-on-a-chip microfluidic device that replicates a portion of a blood vessel endothelium surrounded by a model extracellular matrix. Model blood vessels were fabricated by seeding human umbilical vein endothelial cells on 2, 4, or 6 mg/mL type I collagen hydrogels. Primary human neutrophils were loaded into the endothelial lumens and stimulated by adding the bacterial pathogen Pseudomonas aeruginosa to the surrounding matrix.

Results

Collagen concentration did not affect the cell density or barrier function of the endothelial lumens. Upon infectious challenge, we found greater neutrophil extravasation into the 4 mg/mL collagen gels compared to the 6 mg/mL collagen gels. We further found that extravasated neutrophils had the highest migration speed and distance in 2mg/mL gels and that these values decreased with increasing collagen concentration. However, these phenomena were not observed in the absence of an endothelial lumen. Lastly, no differences in the percent of extravasated neutrophils producing reactive oxygen species were observed across the various collagen concentrations.

Discussion

Our study suggests that neutrophil extravasation and migration in response to an infectious challenge are regulated by collagen concentration in an endothelial cell-dependent manner. The results demonstrate how the mechanical and structural aspects of the tissue microenvironment affect the neutrophil response to infection. Additionally, these findings underscore the importance of developing and using microphysiological systems for studying the regulatory factors that govern the neutrophil response.

Novel strategies for targeting neutrophil against myocardial infarction

Inflammation is a crucial factor in cardiac remodeling after acute myocardial infarction (MI). Neutrophils, as the first wave of leukocytes to infiltrate the injured myocardium, exacerbate inflammation and cardiac injury. However, therapies that deplete neutrophils to manage cardiac remodeling after MI have not consistently produced promising outcomes. Recent studies have revealed that neutrophils at different time points and locations may have distinct functions. Thus, transferring neutrophil phenotypes, rather than simply blocking their activities, potentially meet the needs of cardiac repair. In this review, we focus on discussing the fate, heterogeneity, functions of neutrophils, and attempt to provide a more comprehensive understanding of their roles and targeting strategies in MI. We highlight the strategies and translational potential of targeting neutrophils to limit cardiac injury to reduce morbidity and mortality from MI.

Nanoparticle-neutrophils interactions for autoimmune regulation

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

Changes in Levels of Serum Cytokines and Chemokines in Perforated Appendicitis in Children

Appendicitis is primarily diagnosed based on intraoperative or histopathological findings, and few studies have explored pre-operative markers of a perforated appendix. This study aimed to identify systemic biomarkers to predict pediatric appendicitis at various time points. The study group comprised pediatric patients with clinically suspected appendicitis between 2016 and 2019. Pre-surgical serum interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), intercellular cell-adhesion molecule-1 (ICAM-1), and endothelial selectin (E-selectin) levels were tested from day 1 to day 3 of the disease course. The biomarker values were analyzed and compared between children with normal appendices and appendicitis and those with perforated appendicitis (PA) and non-perforated appendicitis. Among 226 pediatric patients, 106 had non-perforated appendicitis, 102 had PA, and 18 had normal appendices. The levels of all serum proinflammatory biomarkers were elevated in children with acute appendicitis compared with those in children with normal appendices. In addition, the serum IL-6 and TNF-α levels in children with PA were significantly higher, with an elevation in TNF-α levels from days 1 and 2. In addition, serum IL-6 levels increased significantly from days 2 and 3 (both p < 0.05). Serum ICAM-1 and E-selectin levels were elevated in the PA group, with consistently elevated levels within the first three days of admission (all p < 0.05). These results indicate that increased serum levels of proinflammatory biomarkers including IL-6, TNF-α, ICAM-1, and E-selectin could be used as parameters in the prediction and early diagnosis of acute appendicitis, especially in children with PA.

Communications between Neutrophil-Endothelial Interaction in Immune Defense against Bacterial Infection

The endothelial barrier plays a critical role in immune defense against bacterial infection. Efficient interactions between neutrophils and endothelial cells facilitate the activation of both cell types. However, neutrophil activation can have dual effects, promoting bacterial clearance on one hand while triggering inflammation on the other. In this review, we provide a detailed overview of the cellular defense progression when neutrophils encounter bacteria, focusing specifically on neutrophil-endothelial interactions and endothelial activation or dysfunction. By elucidating the underlying mechanisms of inflammatory pathways, potential therapeutic targets for inflammation caused by endothelial dysfunction may be identified. Overall, our comprehensive understanding of neutrophil-endothelial interactions in modulating innate immunity provides deeper insights into therapeutic strategies for infectious diseases and further promotes the development of antibacterial and anti-inflammatory drugs.

The Role of αvβ3 Integrin in Cancer Therapy Resistance

A relevant challenge for the treatment of patients with neoplasia is the development of resistance to chemo-, immune-, and radiotherapies. Although the causes of therapy resistance are poorly understood, evidence suggests it relies on compensatory mechanisms that cells develop to replace specific intracellular signaling that should be inactive after pharmacological inhibition. One such mechanism involves integrins, membrane receptors that connect cells to the extracellular matrix and have a crucial role in cell migration. The blockage of one specific type of integrin is frequently compensated by the overexpression of another integrin dimer, generally supporting cell adhesion and migration. In particular, integrin αvβ3 is a key receptor involved in tumor resistance to treatments with tyrosine kinase inhibitors, immune checkpoint inhibitors, and radiotherapy; however, the specific inhibition of the αvβ3 integrin is not enough to avoid tumor relapse. Here, we review the role of integrin αvβ3 in tumor resistance to therapy and the mechanisms that have been proposed thus far. Despite our focus on the αvβ3 integrin, it is important to note that other integrins have also been implicated in drug resistance and that the collaborative action between these receptors should not be neglected.

Immune Cell Migration to Cancer

Immune cell migration is required for the development of an effective and robust immune response. This elegant process is regulated by both cellular and environmental factors, with variables such as immune cell state, anatomical location, and disease state that govern differences in migration patterns. In all cases, a major factor is the expression of cell surface receptors and their cognate ligands. Rapid adaptation to environmental conditions partly depends on intrinsic cellular immune factors that affect a cell's ability to adjust to new environment. In this review, we discuss both myeloid and lymphoid cells and outline key determinants that govern immune cell migration, including molecules required for immune cell adhesion, modes of migration, chemotaxis, and specific chemokine signaling. Furthermore, we summarize tumor-specific elements that contribute to immune cell trafficking to cancer, while also exploring microenvironment factors that can alter these cellular dynamics within the tumor in both a pro and antitumor fashion. Specifically, we highlight the importance of the secretome in these later aspects. This review considers a myriad of factors that impact immune cell trajectory in cancer. We aim to highlight the immunotherapeutic targets that can be harnessed to achieve controlled immune trafficking to and within tumors.

TruD technology for the study of epi- and endothelial tubes in vitro

Beyond the smallest organisms, animals rely on tubes to transport cells, oxygen, nutrients, waste products, and a great variety of secretions. The cardiovascular system, lungs, gastrointestinal and genitourinary tracts, as well as major exocrine glands, are all composed of tubes. Paradoxically, despite their ubiquitous importance, most existing devices designed to study tubes are relatively complex to manufacture and/or utilize. The present work describes a simple method for generating tubes in vitro using nothing more than a low-cost 3D printer along with general lab supplies. The technology is termed "TruD", an acronym for true dimensional. Using this technology, it is readily feasible to cast tubes embedded in ECM with easy access to the lumen. The design is modular to permit more complex tube arrangements and to sustain flow. Importantly, by virtue of its simplicity, TruD technology enables typical molecular cell biology experiments where multiple conditions are assayed in replicate.

Inflammation and Acinar Cell Dual-Targeting Nanomedicines for Synergistic Treatment of Acute Pancreatitis via Ca2+ Homeostasis Regulation and Pancreas Autodigestion Inhibition

Severe acute pancreatitis (AP) is a life-threatening pancreatic inflammatory disease with a high mortality rate (∼40%). Existing pharmaceutical therapies in development or in clinical trials showed insufficient treatment efficacy due to their single molecular therapeutic target, poor water solubility, short half-life, limited pancreas-targeting specificity, etc. Herein, acid-responsive hollow mesoporous Prussian blue nanoparticles wrapped with neutrophil membranes and surface modified with the N,N-dimethyl-1,3-propanediamine moiety were developed for codelivering membrane-permeable calcium chelator BAPTA-AM (BA) and trypsin activity inhibitor gabexate mesylate (Ga). In the AP mouse model, the formulation exhibited efficient recruitment at the inflammatory endothelium, trans-endothelial migration, and precise acinar cell targeting, resulting in rapid pancreatic localization and higher accumulation. A single low dose of the formulation (BA: 200 μg kg-1, Ga: 0.75 mg kg-1) significantly reduced pancreas function indicators to close to normal levels at 24 h, effectively restored the cell redox status, reduced apoptotic cell proportion, and blocked the systemic inflammatory amplified cascade, resulting in a dramatic increase in the survival rate from 58.3 to even 100%. Mechanistically, the formulation inhibited endoplasmic reticulum stress (IRE1/XBP1 and ATF4/CHOP axis) and restored impaired autophagy (Beclin-1/p62/LC3 axis), thereby preserving dying acinar cells and restoring the cellular "health status". This formulation provides an upstream therapeutic strategy with clinical translation prospects for AP management through synergistic ion homeostasis regulation and pancreatic autodigestion inhibition.

Multi-omic features and clustering phenotypes of circulating tumor cells associated with metastasis and clinical outcomes

Metastasis is a lethal disease of cancer, spreading from primary tumors to the bloodstream as circulating tumor cells (CTCs), which disseminate to distant organs at low efficiency for secondary tumor regeneration, thereby contributing to unfavorable patient outcomes. The detection of dynamic CTC alterations can be indicative of cancer progression (residual cancer, aggressiveness, therapy resistance) or regression (therapy response), serving as biomarkers for diagnoses and prognoses. CTC heterogeneity is impacted by both intrinsic oncogenic changes and extrinsic microenvironmental factors (e.g. the immune system and circadian rhythm), altering the genomic/genetic, epigenomic/epigenetic, proteomic, post-translational, and metabolomic landscapes. In addition to homeostatic dynamics, regenerative stemness, and metabolic plasticity, a newly discovered feature of CTCs that influences metastatic outcomes is its intercellular clustering. While the dogma suggests that CTCs play solo as single cells in the circulation, CTCs can orchestrate with other CTCs or white blood cells to form homotypic or heterotypic multi-cellular clusters, with 20-100 times enhanced metastatic potential than single CTCs. CTC clusters promote cell survival and stemness through DNA hypomethylation and signaling pathways activated by clustering-driving proteins (CD44, CD81, ICAM1, Podocalyxin, etc). Heterotypic CTC clusters may protect CTCs from immune cell attacks if not being cleared by cytotoxic immune cells. This chapter mainly focused on CTC biology related to multi-omic features and metastatic outcomes. We speculate that CTCs could guide therapeutic targeting and be targeted specifically by anti-CTC therapeutics to reduce or eliminate cancer and cancer metastasis.

Current Evidence and Perspectives of Cluster of Differentiation 44 in the Liver's Physiology and Pathology

Cluster of differentiation 44 (CD44), a multi-functional cell surface receptor, has several variants and is ubiquitously expressed in various cells and tissues. CD44 is well known for its function in cell adhesion and is also involved in diverse cellular responses, such as proliferation, migration, differentiation, and activation. To date, CD44 has been extensively studied in the field of cancer biology and has been proposed as a marker for cancer stem cells. Recently, growing evidence suggests that CD44 is also relevant in non-cancer diseases. In liver disease, it has been shown that CD44 expression is significantly elevated and associated with pathogenesis by impacting cellular responses, such as metabolism, proliferation, differentiation, and activation, in different cells. However, the mechanisms underlying CD44's function in liver diseases other than liver cancer are still poorly understood. Hence, to help to expand our knowledge of the role of CD44 in liver disease and highlight the need for further research, this review provides evidence of CD44's effects on liver physiology and its involvement in the pathogenesis of liver disease, excluding cancer. In addition, we discuss the potential role of CD44 as a key regulator of cell physiology.

Syringin alleviates bisphenol A-induced spermatogenic defects and testicular injury by suppressing oxidative stress and inflammation in male zebrafish

Syringin (SRG) is a bioactive principle possessing extensive activities including scavenging of free radicals, inhibition of apoptosis, and anti-inflammatory properties. However, its effects on spermatogenic defects and testicular injury as well as the underlying mechanisms are still unclear. This study aims to investigate the protective effect of SRG on testis damage in zebrafish and explore its potential molecular events. Zebrafish testicular injury was induced by exposure to bisphenol A (BPA) (3000 μg/L) for two weeks. Fish were treated with intraperitoneal injection of SRG at different doses (5 and 50 mg/kg bodyweight) for two more weeks under BPA induction. Subsequently, the testis and sperm were collected for morphological, histological, biochemical and gene expression examination. It was found that the administration of SRG resulted in a significant protection from BPA-caused impact on sperm concentration, morphology, motility, fertility rate, testosterone level, spermatogenic dysfunction and resulted in increased apoptotic and reactive oxygen species' levels. Furthermore, testicular transcriptional profiling alterations revealed that the regulation of inflammatory response and oxidative stress were generally enriched in differentially expressed genes (DEGs) after SRG treatment. Additionally, it was identified that SRG prevented BPA-induced zebrafish testis injury through upregulation of fn1a, krt17, fabp10a, serpina1l and ctss2. These results indicate that SRG alleviated spermatogenic defects and testicular injury by suppressing oxidative stress and inflammation in male zebrafish.

Cancer immunometabolism: advent, challenges, and perspective

For decades, great strides have been made in the field of immunometabolism. A plethora of evidence ranging from basic mechanisms to clinical transformation has gradually embarked on immunometabolism to the center stage of innate and adaptive immunomodulation. Given this, we focus on changes in immunometabolism, a converging series of biochemical events that alters immune cell function, propose the immune roles played by diversified metabolic derivatives and enzymes, emphasize the key metabolism-related checkpoints in distinct immune cell types, and discuss the ongoing and upcoming realities of clinical treatment. It is expected that future research will reduce the current limitations of immunotherapy and provide a positive hand in immune responses to exert a broader therapeutic role.

Is there a role for N1-N2 neutrophil phenotypes in bone regeneration? A systematic review

PURPOSE

This review aims to provide an overview of the multiple functions of neutrophils, with the recognition of the inflammatory (N1) and regenerative (N2) phenotypes, in relation to fracture healing.

METHODS

A literature search was performed using the PubMed database. The quality of the articles was evaluated using critical appraisal checklists.

RESULTS

Thirty one studies were included in this review. These studies consistently support that neutrophils exert both beneficial and detrimental effects on bone regeneration, influenced by Tumor Necrosis Factor-α (TNF-α), Interleukin 8 (IL-8), mast cells, and macrophages. The N2 phenotype has recently emerged as one promoter of bone healing. The N1 phenotype has progressively been connected with inflammatory neutrophils during fracture healing.

CONCLUSIONS

This review has pinpointed various aspects and mechanisms of neutrophil influence on bone healing. The recognition of N1 and N2 neutrophil phenotypes potentially shed new light on the dynamic shifts taking place within the Fracture Hematoma (FH).

Neutrophil and endothelial cell membranes coassembled roflumilast nanoparticles attenuate myocardial ischemia/reperfusion injury

Aim: This study aimed to develop biomimetic nanoparticles (NPs) of roflumilast (ROF) for attenuating myocardial ischemia/reperfusion (MI/R) injury. Materials & methods: We synthesized biomimetic ROF NPs and assembled ROF NPs in neutrophil and endothelial cell membranes (NE/ROF NPs). The physical properties of NE/ROF NPs were characterized and biological functions of NE/ROF NPs were tested in vitro. Targeting characteristics, therapeutic efficacy and safety of NE/ROF NPs were examined in mice model of MI/R. Results: NE/ROF NPs exhibited significant anti-inflammatory and antiadhesion effects. Meanwhile, they was effective in reducing MI/R injury in mice. Furthermore, NE/ROF NPs exhibited stronger targeting capabilities and demonstrated good safety. Conclusion: NE/ROF NPs may be a versatile biomimetic drug-delivery system for attenuating MI/R injury.

Peripheral priming induces plastic transcriptomic and proteomic responses in circulating neutrophils required for pathogen containment

Neutrophils rapidly respond to inflammation and infection, but to which degree their functional trajectories after mobilization from the bone marrow are shaped within the circulation remains vague. Experimental limitations have so far hampered neutrophil research in human disease. Here, using innovative fixation and single-cell-based toolsets, we profile human and murine neutrophil transcriptomes and proteomes during steady state and bacterial infection. We find that peripheral priming of circulating neutrophils leads to dynamic shifts dominated by conserved up-regulation of antimicrobial genes across neutrophil substates, facilitating pathogen containment. We show the TLR4/NF-κB signaling-dependent up-regulation of canonical neutrophil activation markers like CD177/NB-1 during acute inflammation, resulting in functional shifts in vivo. Blocking de novo RNA synthesis in circulating neutrophils abrogates these plastic shifts and prevents the adaptation of antibacterial neutrophil programs by up-regulation of distinct effector molecules upon infection. These data underline transcriptional plasticity as a relevant mechanism of functional neutrophil reprogramming during acute infection to foster bacterial containment within the circulation.

Neutrophil Nanodecoys Inhibit Tumor Metastasis by Blocking the Interaction between Tumor Cells and Neutrophils

Cancer metastasis is the main cause of cancer-related deaths and involves the interaction between tumor cells and neutrophils. In this study, we developed activated neutrophil membrane-coated nanoparticles (aNEM NPs) as nanodecoys to block neutrophil-mediated cancer metastasis. The aNEM NPs were fabricated by cloaking poly(lactic acid) nanoparticles with membranes derived from activated neutrophils and inherited the functional proteins of activated neutrophils. We demonstrated that aNEM NPs could interfere with the recruitment of neutrophils to the primary tumor and premetastatic niches, inhibit the adhesion of neutrophils to tumor vascular endothelium and circulating tumor cells (CTCs), and disrupt the formation of CTC-neutrophil clusters in vitro and in vivo. In 4T1-bearing mice, aNEM NPs could effectively reduce breast cancer metastasis to various organs in mice. Our results suggest that aNEM NPs are a promising nanomedicine for preventing or treating cancer metastasis by acting as neutrophil nanodecoys.

Neutrophil Extracellular DNA Traps in Response to Infection or Inflammation, and the Roles of Platelet Interactions

Neutrophils present the host's first line of defense against bacterial infections. These immune effector cells are mobilized rapidly to destroy invading pathogens by (a) reactive oxygen species (ROS)-mediated oxidative bursts and (b) via phagocytosis. In addition, their antimicrobial service is capped via a distinct cell death mechanism, by the release of their own decondensed nuclear DNA, supplemented with a variety of embedded proteins and enzymes. The extracellular DNA meshwork ensnares the pathogenic bacteria and neutralizes them. Such neutrophil extracellular DNA traps (NETs) have the potential to trigger a hemostatic response to pathogenic infections. The web-like chromatin serves as a prothrombotic scaffold for platelet adhesion and activation. What is less obvious is that platelets can also be involved during the initial release of NETs, forming heterotypic interactions with neutrophils and facilitating their responses to pathogens. Together, the platelet and neutrophil responses can effectively localize an infection until it is cleared. However, not all microbial infections are easily cleared. Certain pathogenic organisms may trigger dysregulated platelet-neutrophil interactions, with a potential to subsequently propagate thromboinflammatory processes. These may also include the release of some NETs. Therefore, in order to make rational intervention easier, further elucidation of platelet, neutrophil, and pathogen interactions is still needed.

An Intriguing Structural Modification in Neutrophil Migration Across Blood Vessels to Inflammatory Sites: Progress in the Core Mechanisms

The role and function of neutrophils are well known, but we still have incomplete understanding of the mechanisms by which neutrophils migrate from blood vessels to inflammatory sites. Neutrophil migration is a complex process that involves several distinct steps. To resist the blood flow and maintain their rolling, neutrophils employ tether and sling formation. They also polarize and form pseudopods and uropods, guided by hierarchical chemotactic agents that enable precise directional movement. Meanwhile, chemotactic agents secreted by neutrophils, such as CXCL1, CXCL8, LTB4, and C5a, can recruit more neutrophils and amplify their response. In the context of diapedesis neutrophils traverse the endothelial cells via two pathways: the transmigratory cup and the lateral border recycling department. These structures aid in overcoming the narrow pore size of the endothelial barrier, resulting in more efficient transmembrane migration. Interestingly, neutrophils exhibit a preference for the paracellular pathway over the transcellular pathway, likely due to the former's lower resistance. In this review, we will delve into the intricate process of neutrophil migration by focusing on critical structures that underpins this process.