Inflammation. Neutrophil extracellular traps license macrophages for cytokine production in atherosclerosis

Innate immune cells in vascular lesions: mechanism and significance of diversified immune regulation

Angiogenesis is a complex physiological process. In recent years, the immune regulation of angiogenesis has received increasing attention, and innate immune cells, which are centred on macrophages, are thought to play important roles in vascular neogenesis and development. Various innate immune cells can act on the vasculature through a variety of mechanisms, with commonalities as well as differences and synergistic effects, which are crucial for the progression of vascular lesions. In recent years, monotherapy with antiangiogenic drugs has encountered therapeutic bottlenecks because of the short-term effect of 'vascular normalization'. The combination treatment of antiangiogenic therapy and immunotherapy breaks the traditional treatment pattern. While it has a remarkable curative effect and survival benefits, it also faces many challenges. This review focuses on innate immune cells and mainly introduces the regulatory mechanisms of monocytes, macrophages, natural killer (NK) cells, dendritic cells (DCs) and neutrophils in vascular lesions. The purpose of this paper was to elucidate the underlying mechanisms of angiogenesis and development and the current research status of innate immune cells in regulating vascular lesions in different states. This review provides a theoretical basis for addressing aberrant angiogenesis in disease processes or finding new antiangiogenic immune targets in inflammation and tumor.

Targeting Immune Cell Metabolism: A Promising Therapeutic Approach for Cardiovascular Disease

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality globally. Recent groundbreaking preclinical and clinical research underscores the pivotal role of metabolite remodelling in the pathology of CVD. This metabolic transformation not only directly fuels the progression of CVD but also profoundly influences the immune response within the cardiovascular system. In this review, we focused on the complex interactions between cardiovascular metabolic alterations and immune responses during the course of CVD. Furthermore, we explore the potential therapeutic interventions that could be developed based on the understanding of metabolic alterations and immune dysregulation in CVD. By targeting these metabolic and immunological pathways, novel strategies for the prevention and treatment of CVDs might be developed to improve patient outcomes and reduce the global burden of this disease.

Advances in research of neutrophil extracellular trap formation in osteoarticular diseases

Neutrophil extracellular traps (NETs) have been the subject of research in the field of innate immunity since they were first described two decades ago. NETs are fibrous network structures released by neutrophils under specific stimuli, including DNA, histones, and a variety of granular proteins. NETs have been widely studied in the fields of infectious and immune diseases, and new breakthroughs have been made in the understanding of disease pathogenesis and treatment. In recent years, studies have found that NETs play an important role in the occurrence and development of osteoarticular diseases. This article reviews the progress in the research of NETs in common osteoarticular diseases such as rheumatoid arthritis, ankylosing spondylitis, gouty arthritis, osteonecrosis of the femoral head, osteoarthritis, and joint fibrosis, including the formation mechanism of NETs and its role in inflammation, joint destruction, pain and other pathological processes. The problems existing in current research are discussed, along with future research directions, to provide a reference for the in-depth study of osteoarticular diseases and the development of new treatment strategies.

Advancements in the study of short-chain fatty acids and their therapeutic effects on atherosclerosis

Atherosclerosis (AS) remains a leading cause of cardiovascular disease and mortality globally. This chronic condition is characterized by inflammation, lipid accumulation, and the deposition of cellular components within arterial walls. Emerging evidence has highlighted the multifaceted therapeutic potential of short-chain fatty acids (SCFAs) in mitigating AS progression. SCFAs have demonstrated anti-inflammatory properties and the ability to regulate immune responses, metabolic pathways, vascular integrity, and intestinal barrier function in animal models of AS. Consequently, SCFAs have garnered significant attention as a promising approach for the prevention and treatment of AS. However, further clinical trials and studies are necessary to fully elucidate the underlying mechanisms and effects of SCFAs. Additionally, different types of SCFAs may exert distinct impacts, necessitating more in-depth investigation into their specific roles and mechanisms. This review provides an overview of the diverse cellular mechanisms contributing to AS formation, as well as a discussion of the significance of SCFAs in AS pathogenesis and their multifaceted therapeutic potential. Nonetheless, additional research is warranted to comprehensively understand and harness the potential of various SCFAs in the context of AS.

Mechanisms and immune crosstalk of neutrophil extracellular traps in response to infection

Neutrophil extrusion of neutrophil extracellular traps (NETs) in a process called NETosis provides immune defense against extracellular bacteria. It has been observed that bacteria are capable of activating neutrophils to release NETs that subsequently kill them or at least prevent their local spread within host tissue. However, existing studies have mainly focused on the isolated function of NETs, with less attention given to their anti-bacterial mechanisms through interactions with other immune cell populations. The net effect of these complex intercellular interactions, which may act additively, synergistically, or antagonistically, is a critical determinant in the outcomes of host-pathogen interactions. This review summarizes the mechanisms underlying classic NET formation and their crosstalk with the immune system, offering novel insights aimed at balancing the anti-microbial function with their potential inflammatory risks.

Association between neutrophil count and the risk of cardiovascular disease: A community-based cohort study in Taiwan

BACKGROUND

Neutrophil count is associated with atherosclerotic plaque formation and cardiovascular diseases (CVD). As previous studies have been predominantly conducted in Caucasians, the significance of neutrophil count as a clinical factor in CVD in other ethnicities remain unclear.

METHODS

A total of 2,955 participants from the Chin-Shan Community Cardiovascular Study(CCCC), who had no established CVD diagnosis and missing data, were enrolled in this study and followed from 1990-1991-2013. We use Cox regression models to calculate hazard ratio (HR) and 95% confidence interval (CI) to evaluate the association between neutrophil count and CVD risk. Subgroup analyses were performed based on sex and age, while sensitivity analyses were conducted by excluding participants with extreme values.

RESULTS

Over a median follow-up period of 22 years, 400 cases of new-onset CVD were recorded. Cox proportional hazards regression analysis revealed that a higher neutrophil count was independently associated with CVD incidence in Taiwanese adults, with an HR of 1.42 (95% CI 1.03-1.94) after adjusting for multiple covariates. This association remained consistent in both the subgroup and sensitivity analyses.

CONCLUSION

Our study demonstrated that, in the Taiwanese population, a higher neutrophil count was associated with a higher incidence of CVD over an average 22-year follow-up in individuals without preexisting CVD.

Neutrophils in Tissue Injury and Repair: Molecular Mechanisms and Therapeutic Targets

Tissue repair represents a highly intricate and ordered dynamic process, critically reliant on the orchestration of immune cells. Among these, neutrophils, the most abundant leukocytes in the body, emerge as the initial immune responders at injury sites. Traditionally recognized for their antimicrobial functions in innate immunity, neutrophils now garner attention for their indispensable roles in tissue repair. This review delves into their novel functions during the early stages of tissue injury. We elucidate the mechanisms underlying neutrophil recruitment and activation following tissue damage and explore their contributions to vascular network formation. Furthermore, we investigate the pivotal role of neutrophils during the initial phase of repair across different tissue types. Of particular interest is the investigation into how the fate of neutrophils influences overall tissue healing outcomes. By shedding light on these emerging aspects of neutrophil function in tissue repair, this review aims to pave the way for novel strategies and approaches in future organ defect repair, regeneration studies, and advancements in tissue engineering. The insights provided here have the potential to significantly impact the field of tissue repair and regeneration.

Inflammasome Activation and Neutrophil Extracellular Traps in Atherosclerosis

The deposition of cholesterol containing cholesterol crystals and the infiltration of immune cells are features of atherosclerosis. Although the role of cholesterol crystals in the progression of atherosclerosis have long remained unclear, recent studies have clarified the involvement of cholesterol crystals in inflammatory responses. Cholesterol crystals activate the NLRP3 inflammasome, a molecular complex involved in the innate immune system. Activation of NLRP3 inflammasomes in macrophages cause pyroptosis, which is accompanied by the release of inflammatory cytokines such as IL-1β and IL-1α. Furthermore, NLRP3 inflammasome activation drives neutrophil infiltration into atherosclerotic plaques. Cholesterol crystals trigger NETosis against infiltrated neutrophils, a form of cell death characterized by the formation of neutrophil extracellular traps (NETs), which, in turn, prime macrophages to enhance inflammasome-mediated inflammatory responses. Colchicine, an anti-inflammatory drug effective in cardiovascular disease, is expected to inhibit cholesterol crystal-induced NLRP3 inflammasome activation and neutrophil infiltration. In this review, we illustrate the reinforcing cycle of inflammation that is amplified by inflammasome activation and NETosis.

Role of Hemoglobin-Stimulated Macrophages and Intraplaque Hemorrhage in the Development of Vascular Diseases

Intraplaque hemorrhage plays a critical role in the life of advancing atherosclerotic plaques, not only by triggering an acute increase in lesion size but also by attracting macrophages to the site. Lysis of erythrocytes in these areas is thought to be caused by oxidative stress, which induces the release of free Hb (hemoglobin), which is quickly bound by haptoglobin to form Hb-haptoglobin complexes. Macrophages are the only cells in the body capable of scavenging these complexes through the CD (cluster of differentiation) 163 scavenger receptor, which mediates Hb-haptoglobin ingestion, driving their differentiation. Emerging data suggest that these Hb-stimulated macrophages play an essential role in responding to intraplaque hemorrhage through mediating iron metabolism and influencing other cell types, including endothelial and smooth muscle cells. This review focuses on the role of Hb-stimulated macrophages in promoting atherogenesis through their effects on (1) endothelial activation, neoangiogenesis, and vascular permeability; (2) endothelial-to-mesenchymal cell transition and subsequent apoptosis; and (3) the prevention of smooth muscle cell osteogenic transformation and calcification. These functions may also be relevant to other vascular diseases where erythrocyte accumulation drives the formation of Hb-stimulated macrophages, which is a fundamental response to hemorrhage no matter the clinical setting.

Cholesterol crystals in the pathogenesis of atherosclerosis

The presence of cholesterol crystals (CCs) in tissues was first described more than 100 years ago. CCs have a pathogenic role in various cardiovascular diseases, including myocardial infarction, aortic aneurysm and, most prominently, atherosclerosis. Although the underlying mechanisms and signalling pathways involved in CC formation are incompletely understood, numerous studies have highlighted the existence of CCs at various stages of atheroma progression. In this Review, we summarize the mechanisms underlying CC formation and the role of CCs in cardiovascular disease. In particular, we explore the established links between lipid metabolism across various cell types and the formation of CCs, with a focus on CC occurrence in the vasculature. We also discuss CC-induced inflammation as one of the pathogenic features of CCs in the atheroma. Finally, we summarize the therapeutic strategies aimed at reducing CC-mediated atherosclerotic burden, including approaches to inhibit CC formation in the vasculature or to mitigate the inflammatory response triggered by CCs. Addressing CC formation might emerge as a crucial component in our broader efforts to combat cardiovascular disease.

Higher Neutrophil-Percentage-to-Albumin Ratio Was Associated with Poor Outcome in Endovascular Thrombectomy Patients

Background and Purpose

The neutrophil percentage-to-albumin ratio (NPAR) is connected with all-cause mortality and stroke-related pneumonia. The purpose of this study was to assess the diagnostic efficacy of NPAR in predicting functional outcomes at 90 days after endovascular thrombectomy (EVT).

Methods

We retrospective analyzed consecutive patients who underwent EVT at Nanjing First Hospital from October 2019 to June 2024. NPAR was defined as the percentage of neutrophils divided by the albumin levels. An unfavorable outcome was indicated by a modified Rankin Scale score of 3-6 at 90 days. Multivariable logistic regression models were utilized to investigate the association between NPAR and functional outcomes after EVT treatment.

Results

A total of 713 patients (mean age, 70.5 ± 11.9 years; 430 males) were finally enrolled for analysis. Among these, 357 (50.1%) patients exhibited unfavorable outcomes at 90 days. Multivariate regression analysis indicated that elevated NPAR levels at admission were independently associated with poor outcome (adjusted odds ratio: 6.921; 95% confidence interval, 4.216-11.363; P=0.001) in ischemic stroke patients undergoing EVT. Furthermore, the restricted cubic spline observed a positive and nonlinear association between the NPAR and poor outcome at 90 days (P for linearity=0.001).

Conclusion

This study indicated that higher NPAR levels were associated an increased risk of poor outcome at 90 days in patients treated with EVT, suggesting that NPAR could serve as a viable prognostic biomarker for ischemic stroke after EVT.

Unraveling the significance of innate inflammation in vascular disease

Atheroma formation is initiated by the activation of endothelial and smooth muscle cells, as well as immune cells, including neutrophils, lymphocytes, monocytes, macrophages, and dendritic cells. Monocytes, macrophages, and neutrophils are the innate immune cells that provide a rapid initial line of defence against vascular disease. These cells have a short lifespan and cannot retain memories, making them potential therapeutic targets for the inflammatory process associated with atherosclerosis. In addition, macrophages comprise the majority of vessel wall infiltrates and are, therefore, implicated in all stages of atherosclerosis progression. Neutrophils are the most common type of leukocyte found in circulation, and their high levels of matrix-degrading protease explain their significance in fibrous cap destabilization. However, the activation of immune cells becomes more complex by various microenvironmental stimuli and cytokines, which ultimately transform immune cells into their pro-inflammatory state. Different types of macrophage subsets with distinct functions in inflammation, such as M1 macrophages, cause an increase in pro-inflammatory cytokines and produce reactive oxygen species and nitric oxide, further worsening the disease. This review aims to shed light on immune-mediated inflammation in cardiovascular disease by focusing on the role of macrophage subsets in vascular inflammation and plaque stability, as well as the interaction between neutrophils and monocyte-macrophages.

Exosomes and MicroRNAs: key modulators of macrophage polarization in sepsis pathophysiology

Sepsis is a highly dangerous and complex condition that can result in death. It is characterized by a strong reaction to an infection, causing dysfunction in multiple bodily systems and a high risk of mortality. The transformation of macrophages is a vital stage in the procedure as they possess the capability to interchange between two separate types: M1, which promotes inflammation, and M2, which inhibits inflammation. The choice greatly affects the immune response of the host. This analysis underscores the rapidly expanding roles of exosomes and microRNAs (miRNAs) in regulating the trajectory of macrophage polarization during episodes of sepsis. Exosomes, extremely small extracellular vesicles, facilitate cellular communication by transferring biologically active compounds, including miRNAs, proteins, and lipids. We investigate the impact of changes in exosome production and composition caused by sepsis on macrophage polarization and function. Unique microRNAs present in exosomes play a significant role in controlling crucial signaling pathways that govern the phenotype of macrophages. Through thorough examination of recent progress in this area, we clarify the ways in which miRNAs derived from exosomes can either aggravate or alleviate the inflammatory reactions that occur during sepsis. This revelation not only deepens our comprehension of the underlying mechanisms of sepsis, but it also reveals potential new biomarkers and targets for treatment. This assessment aims to amalgamate diverse research investigations and propose potential avenues for future investigations on the influence that exosomes and miRNAs have on macrophage polarization and the body's response to sepsis. These entities are essential for controlling the host's reaction to sepsis and hold important functions in this mechanism.

Deep insight into cytokine storm: from pathogenesis to treatment

Cytokine storm (CS) is a severe systemic inflammatory syndrome characterized by the excessive activation of immune cells and a significant increase in circulating levels of cytokines. This pathological process is implicated in the development of life-threatening conditions such as fulminant myocarditis (FM), acute respiratory distress syndrome (ARDS), primary or secondary hemophagocytic lymphohistiocytosis (HLH), cytokine release syndrome (CRS) associated with chimeric antigen receptor-modified T (CAR-T) therapy, and grade III to IV acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation. The significant involvement of the JAK-STAT pathway, Toll-like receptors, neutrophil extracellular traps, NLRP3 inflammasome, and other signaling pathways has been recognized in the pathogenesis of CS. Therapies targeting these pathways have been developed or are currently being investigated. While novel drugs have demonstrated promising therapeutic efficacy in mitigating CS, the overall mortality rate of CS resulting from underlying diseases remains high. In the clinical setting, the management of CS typically necessitates a multidisciplinary team strategy encompassing the removal of abnormal inflammatory or immune system activation, the preservation of vital organ function, the treatment of the underlying disease, and the provision of life supportive therapy. This review provides a comprehensive overview of the key signaling pathways and associated cytokines implicated in CS, elucidates the impact of dysregulated immune cell activation, and delineates the resultant organ injury associated with CS. In addition, we offer insights and current literature on the management of CS in cases of FM, ARDS, systemic inflammatory response syndrome, treatment-induced CRS, HLH, and other related conditions.

Exploring the Roles of Liver X Receptors in Lipid Metabolism and Immunity in Atherosclerosis

Hypercholesterolemia causes atherosclerosis by inducing immune cell migration and chronic inflammation in arterial walls. Recent single-cell analyses reveal the presence of lipid-enriched foamy macrophages, as well as other macrophage subtypes, neutrophils, T cells, and B cells, in atherosclerotic plaques in both animal models and humans. These cells interact with each other and other cells, including non-immune cells such as endothelial cells and smooth muscle cells. They thereby regulate metabolic, inflammatory, phagocytic, and cell death processes, thus affecting the progression and stability of atherosclerotic plaques. The nuclear receptors liver X receptor (LXR)α and LXRβ are transcription factors that are activated by oxysterols and regulate lipid metabolism and immune responses. LXRs regulate cholesterol homeostasis by controlling cholesterol's transport, absorption, synthesis, and breakdown in the liver and intestine. LXRs are also highly expressed in tissue-resident and monocyte-derived macrophages and other immune cells, including both myeloid cells and lymphocytes, and they regulate both innate and adaptive immune responses. Interestingly, LXRs have immunosuppressive and immunoregulatory functions that are cell-type-dependent. In animal models of atherosclerosis, LXRs have been shown to be involved in both progression and regression phases. The pharmacological activation of LXR enhances cholesterol efflux from macrophages and promotes atherosclerosis progression. Deleting LXR in immune cells, especially myeloid cells, accelerates atherosclerosis by increasing monocyte migration, macrophage proliferation and activation, and neutrophil extracellular traps (NETs); furthermore, the deletion of hematopoietic LXRs impairs the regression of atherosclerotic plaques. Therefore, LXRs in immune cells may be a potent therapeutic target for atherosclerosis.

NETs activate the GAS6-AXL-NLRP3 axis in macrophages to drive morphine tolerance

BACKGROUND

The development of morphine tolerance presents a major clinical challenge in the effective management of severe pain. This study aims to explore the mechanisms underlying morphine tolerance from a novel perspective, with the ultimate goal of uncovering new insights and identifying promising therapeutic targets for its treatment.

METHODS

C57BL/6J mice were used in the tail-flick test to evaluate morphine tolerance. Neutrophils derived from mouse bone marrow were employed to investigate the mechanisms underlying morphine-induced NETs formation. Bone marrow-derived macrophages (BMDMs) were harvested from the femur and tibia to study the role of NETs-induced inflammation in analgesic tolerance. Proinflammatory cytokines were measured using Western blotting and real-time PCR. The levels of NETs and the TLR7/9-NLRP3-related signaling pathway were assessed through Western blotting, real-time PCR, and ELISA. Confocal laser scanning microscopy was utilized to visualize NETs in the dorsal root ganglion (DRG) and in cells.

RESULTS

Our experiments demonstrated that the levels of NETs in the plasma of patients using morphine for analgesia, as well as in morphine-tolerant animals, were significantly elevated. Genetic elimination of Pad4, neutrophil depletion, and treatment with DNase 1 and RNase A to disrupt NETs formation all effectively alleviated morphine tolerance. These findings indicate that NETs play a critical role in the development of morphine tolerance. Mechanistically, we discovered that morphine-induced NETs can be engulfed by macrophages through the GAS6-AXL axis, which subsequently triggers the activation of the TLR7/TLR9-mediated NLRP3 inflammasome, leading to significantly increased levels of IL-1β and IL-18, and ultimately contributing to tolerance. Deletion of Axl, Gas6, or Nlrp3 each significantly improved morphine tolerance. Furthermore, in the murine model, treatment with the IL-1 receptor antagonist anakinra and the IL-18 decoy receptor IL-18BP prevented the development of morphine tolerance.

CONCLUSIONS

This study identifies morphine-induced NETs as a key contributor to morphine tolerance, with the GAS6-AXL-TLR7/9 axis emerging as a potential therapeutic target. Strategies focused on disrupting NETs and modulating this axis may offer a promising approach to combat morphine tolerance.

CXCL2: a key player in the tumor microenvironment and inflammatory diseases

CXCL2 (C-X-C Motif Chemokine Ligand 2), a constituent of the C-X-C chemokine subfamily, serves as a powerful chemotactic factor for neutrophils, facilitating leukocyte recruitment and movement while initiating an inflammatory response. Recent investigations have demonstrated the pivotal involvement of CXCL2 in carcinogenesis. Within the tumor microenvironment, CXCL2 modulates cellular activity primarily via its interaction with the CXCR2 receptor. The activation of signaling pathways, including ERK/MAPK, NF-κB/MAPK, PI3K/AKT, and JAK/STAT3, highlights CXCL2's inclination to promote tumorigenesis. Furthermore, the role of CXCL2 encompasses inflammatory conditions like lung inflammation, atherosclerosis, and obesity. This article examines the structural characteristics, biological roles, and molecular foundation of CXCL2 in carcinogenesis and inflammatory disorders.

Procoagulant Effect of Neutrophil Extracellular Traps, Activated Platelets, and Endothelial Cells in Patients After TAVR

BACKGROUND

Patients with severe aortic stenosis, undergoing transcatheter aortic valve replacement (TAVR), are more likely to develop thrombotic complications. However, the definite mechanisms underlying the hypercoagulation state remain unclear to date. Our objectives were to explore whether and how neutrophil extracellular traps (NETs) play a procoagulant role in patients after TAVR alone or TAVR with percutaneous coronary intervention within 1 year and further to evaluate their interactions with platelets and endothelial cells.

METHODS

The levels of plasma NETs, platelets, and endothelial cell activation markers were analyzed by ELISA. NET formation was observed by immunofluorescence. Procoagulant activity was measured by clotting time, fibrin, and TAT (thrombin-antithrombin) complex generation assays. Phosphatidylserine exposure on cells was assessed by flow cytometry.

RESULTS

Compared with pre-TAVR, controls, or severe aortic stenosis without TAVR patients, the plasma NET levels in patients after TAVR alone, especially TAVR with percutaneous coronary intervention, increased from 7 days, peaking at 3 months, and then gradually decreased until the 12th month. Furthermore, neutrophils and plasma from patients post-TAVR are more prone to promote NET formation; NETs from these patients markedly decreased clotting time and increased fibrin and TAT generation. Additionally, a high concentration of NETs induced platelet aggregation and exerted a strong cytotoxic effect on endothelial cells and transformed them into a procoagulant phenotype.

CONCLUSIONS

These results lead us to believe that NETs contribute to the hypercoagulability in patients post-TAVR. Our study may provide a new target for preventing thrombotic complications in patients post-TAVR by blocking NET generation.

Inflammasomes and Cardiovascular Disease: Linking Inflammation to Cardiovascular Pathophysiology

Cardiovascular diseases (CVDs) remain a leading cause of global mortality, driven by risk factors such as dyslipidemia, hypertension and diabetes. Recent research has highlighted the critical role of inflammasomes, particularly the NLRP3 inflammasome, in the pathogenesis of various CVDs, including hypertension, atherosclerosis, myocardial infarction and heart failure. Inflammasomes are intracellular protein complexes that activate inflammatory responses through the production of pro-inflammatory cytokines such as IL-1β and IL-18, contributing to endothelial dysfunction, plaque formation and myocardial injury. This review provides a comprehensive overview of the structure, activation mechanisms and pathways of inflammasomes, with a focus on their involvement in cardiovascular pathology. Key activation pathways include ion fluxes (K+ efflux and Ca2+ signalling), endoplasmic reticulum (ER) stress, mitochondrial dysfunction and lysosomal destabilisation. The review also explores the therapeutic potential of targeting inflammasomes to mitigate inflammation and improve outcomes in CVDs. Emerging strategies include small-molecule inhibitors, biologics and RNA-based therapeutics, with a particular emphasis on NLRP3 inhibition. Additionally, the integration of artificial intelligence (AI) in cardiovascular research offers promising avenues for identifying novel biomarkers, predicting disease risk and developing personalised treatment strategies. Future research directions should focus on understanding the interactions between inflammasomes and other immune components, as well as genetic regulators, to uncover new therapeutic targets. By elucidating the complex role of inflammasomes in CVDs, this review underscores the potential for innovative therapies to address inflammation-driven cardiovascular pathology, ultimately improving patient outcomes.

Comparing the therapeutic influence of bone marrow Mesenchymal stem cells versus its derived exosomes against diabetic hepatopathy in rats

Diabetes mellitus (DM) is a chronic widespread metabolic disorder, involving a high blood glucose level which causes multiple serious complications including liver, kidney, brain and peripheral nerves damage. Due to the undesirable side effects of the anti-diabetic drugs, the current studies directed to use stem cells and exosomes to overcome the limitations of traditional therapy. We aimed to compare the antidiabetic effect of Bone marrow mesenchymal stem cells (BMMSCs) and its derived exosomes against diabetic hepatopathy induced by streptozotocin (STZ) in albino rats. Our study was conducted on 28 male albino rats divided into 4 groups {control negative non diabetic group, control positive diabetic group, exosomes treated group received (5 × 109 particle/rat) through tail vein twice per week for one month} and Stem cell treated group received (107) BMMSCs through tail vein twice per week for one month. Hepatic structure together with blood glucose level, liver function enzymes were assayed in addition to a lipid profile tests, oxidative stress, and gene expression. Both treated groups by exosomes and stem cells expressed significantly low levels of fasting blood glucose, liver function parameters (ALT, AST, ALP), lipid profile tests (cholesterol and triglycerides), lipid peroxidation index (MDA), with substantial reduction in IL-1β expression compared to diabetic group. Significantly downregulating the VEGF and elevation of eNOS genes and GSH which suggest the effective role provided by BMMSCs and its derived exosomes for treatment of diabetic hepatopathy. Although, the results of both groups showed near average outcomes, the exosome treated group significantly enhanced liver function enzymes and triglyceride, cholesterol level compared to stem cells treated group. These findings were reinforced by the histopathological and immunohistochemistry examination. The latter showed slight but non-significant improvements in VEGF, eNOS, and IL-1β expression. These minor differences together with practical advantages of exosomes make it preferable over BMMSCs in treatment of diabetic hepatopathy.

Colchicine Attenuates Microvascular Obstruction after Myocardial Ischemia-Reperfusion Injury by Inhibiting the Proliferation of Neutrophil in Bone Marrow

PURPOSE

Complete and rapid recanalization of blood flow by percutaneous coronary intervention (PCI) is the most effective intervention for patients with ST-segment elevation myocardial infarction (STEMI). However, myocardial ischemia/reperfusion (I/R) injury leads to microvascular obstruction (MVO), limiting its efficacy. Colchicine can reduce myocardial I/R injury, but its effect on MVO is unclear. Hence, this study aimed to assess the role and mechanism of colchicine on MVO.

METHODS

Clinical data on STEMI patients with PCI were collected and risk factors related to MVO were analyzed. The rat myocardial I/R model was established to evaluate the MVO by thioflavin S staining. The myocardial I/R model of mice was treated with PBS or colchicine at the reperfusion. The effect of colchicine on cardiomyocyte apoptosis after I/R was evaluated by TUNEL and expression of cleaved caspase-3. ROS levels were detected in H9c2 cells to evaluate the colchicine effect on myocardial oxidative stress. Moreover, the mechanism through which colchicine attenuated MVO was examined using flow cytometry, WB, ELISA, immunohistochemistry, bioinformatics analysis, and immunofluorescence.

RESULTS

Multivariate analysis showed that elevated neutrophils were associated with extensive MVO. Colchicine could attenuate MVO and reduce neutrophil recruitment and NETs formation after myocardial I/R. In addition, colchicine inhibited cardiomyocyte apoptosis in vivo and ROS levels in vitro. Furthermore, colchicine inhibited neutrophil proliferation in the bone marrow (BM) by inhibiting the S100A8/A9 inflammatory signaling pathway.

CONCLUSIONS

Colchicine attenuated MVO after myocardial I/R injury by inhibiting the proliferation of neutrophils in BM through the neutrophil-derived S100A8/A9 inflammatory signaling pathway.

Saturated fatty acid-induced neutrophil extracellular traps contribute to exacerbation and biologic therapy resistance in obesity-related psoriasis

Psoriasis patients who are obese tend to have serious clinical manifestations and poor responses to various biological agents in most cases. However, the mechanisms by which obesity exacerbates psoriasis remain enigmatic. In this study, we found that the abundance of systemic and localized cutaneous neutrophil extracellular traps (NETs) associated with the obesity-induced aggravation of psoriasis was positively correlated with disease severity and that the inhibition of NETs alleviated psoriatic dermatitis in obese mice. Mechanistically, we found that changes in fatty acid composition in obese subjects resulted in the deposition of saturated fatty acids (SFAs), which promoted the release of NETs via the TLR4-MD2/ROS signaling pathway. We further revealed that NETs potentiate IL-17 inflammation, especially γδT17-mediated immune responses, in obesity-exacerbated psoriasis patients. Moreover, SFAs induced a decreased response to anti-IL17A treatment in psoriasis-like mice, whereas the inhibition of NETs improved the beneficial effects of anti-IL17A in psoriasis-like mice with lipid metabolism disorders. Our findings collectively suggest that SFA-induced NETs play a critical role in the exacerbation of obesity-related psoriasis and provide potential new strategies for the clinical treatment of refractory psoriasis patients with lipid metabolism disorders.

Neutrophil Extracellular Traps in Oral Diseases

OBJECTIVE

To summarize the current knowledge of the neutrophil extracellular traps (NETs) and its critical role in various oral diseases.

METHODS

We reviewed the recent research on NETs through PubMed and Web of Science. An analysis of recent research results was summarized from three aspects: NETs induction and formation, functions of NETs, and NETs in oral diseases.

RESULTS

The relationship between neutrophils and NETs is critical to the body's defense against microbial invasion. NETs can effectively combat pathogens with an anti-inflammatory effect and meanwhile it can contribute to inflammation. Moreover, it can synergize with other immune cells to respond to stimuli, such as pathogens, host-derived mediators, and drugs. It was revealed that NETs play different roles to influence various oral diseases like periodontitis, endodontic infection, oral mucosal diseases, maxillofacial tumors, and many other oral diseases.

CONCLUSION

The balance between the protective and potentially harmful effects of NETs is a key factor in determining the outcome of infections and inflammatory responses. The role of NETs in oral diseases needs to be further studied to enable better understanding of its role in the different oral diseases.

Th17 Cells in Cardiovascular Disease

Recent research has shown a strong link between Th17 cells and their cytokine IL-17, and various cardiovascular diseases such as atherosclerosis, myocardial infarction, myocarditis, and arrhythmia. Moreover, Th17 cell signalling is likely to be a key factor in cardiovascular disease. Here, we summarize recent advances in the source, function, regulation, and the effects of Th17 signaling in cardiovascular disease. Research on Th17 will suggest more specific strategies to manipulate these functions. Thus, effective treatment of cardiovascular disease and future clinical treatment will be possible.

Is L-Arginine an Appropriate Alternative for Conventional Anti-Atherosclerotic Therapy?: A Comprehensive Review

Background

Atherosclerosis is the leading cause of cardiovascular disease (CVD). Historically, the management of atherosclerosis was focused on decreasing lipid profile levels; however, recent evidence demonstrated that platelets and leukocytes play an important role in forming and exacerbating atherosclerosis. L-arginine (L-Arg), a precursor to nitric oxide (NO), plays a critical role in modulating oxidative stress and influencing platelet-leukocyte recruitment and has been extensively addressed in the context of CVD.

Objective

We aimed to perform a comprehensive literature review on l-Arg metabolism in the causative pathway of atherosclerosis compared to conventional treatment and it as a putative therapeutic approach.

Results

L-Arg supplementation has shown promising effects on NO production, improving endothelial function and reducing oxidative stress in preclinical models. Clinical studies have indicated moderate improvements in vascular health markers, including reductions in inflammation and oxidative stress, although results have varied across studies. The potential of l-Arg to modify platelet-leukocyte recruitment and slow the progression of atherosclerotic plaque development has been observed in certain studies. However, these benefits remain inconsistent, and more robust clinical trials are needed to confirm its effectiveness. Additionally, while l-Arg appears to be relatively safe, some studies reported mild gastrointestinal discomfort as a common side effect.

Conclusion

l-Arg holds potential as a complementary or alternative treatment for atherosclerosis, particularly in improving endothelial function and reducing inflammation and oxidative stress. However, the variability in clinical outcomes and the lack of long-term data required further investigation into assessing therapeutic benefits. Future studies should focus on determining optimal dosing regimens, evaluating their long-term safety, and assessing their potential in combination with other therapies to enhance cardiovascular outcomes.

A patent review of peptidylarginine deiminase 4 (PAD4) inhibitors (2014-present)

INTRODUCTION

PAD4 mediates the post-translational modification of arginine residues into citrulline which can have profound effects on protein structure, function and interactions. Protein citrullination and neutrophil extracellular trap (NET) formation associated with increased PAD4 activity have been implicated in the development of autoimmune conditions, cardiovascular diseases, neurodegenerative disorders, and cancer. PAD4 inhibitors have been shown to suppress citrullination and NETs formation.

AREAS COVERED

This review covers 10 years of industrial drug discovery campaigns reported in 28 patent applications from 10 companies. Cortellis, the World Intellectual Property Organization website, Scopus and SciFinder were used to search the patent literature using the keywords 'PAD4' and 'PAD4 inhibitor.' Most of the reported inhibitors share the same core scaffold with varied decoration of different complexity, including highly functionalized macrocycles, with some in vivo and pharmacokinetic (PK) data reported for selected examples.

EXPERT OPINION

Despite PAD4's clear involvement in multiple disease pathways, its detailed mechanism remains insufficiently understood. Selective and potent compounds with improved PK properties have been provided but most research on PAD4 is still at the experimental stage or preclinical development; the most promising is JBI-1044, at the IND stage, while some companies have turned to antibodies despite considerable previous investment in small molecules.

The Role of Neutrophil Extracellular Traps in Atherosclerosis: From the Molecular to the Clinical Level

Atherosclerosis is a chronic inflammatory condition that is typified by the deposition of lipids and the subsequent inflammation of medium and large arteries. Neutrophil extracellular traps (NETs) are fibrous meshworks of DNA, histones, and granzymes expelled by activated neutrophils in response to a variety of pathogenic conditions. In addition to their role in pathogen eradication, NETs have been demonstrated to play a pivotal role in the development of atherosclerosis. This article presents a review of the bidirectional interactions in which atherosclerosis-related risk factors stimulate the formation of NETs, which in turn support disease progression. This article emphasizes the involvement of NETs in the various stages of atherogenesis and development, influencing multiple factors such as the vascular endothelium, platelets, the inflammatory milieu, and lipid metabolism. The findings of this study offer new insights and avenues for further investigation into the processes underlying the formation and regulation of the vascular inflammatory microenvironment in atherosclerosis. Finally, potential targeted therapeutic strategies for NETs are discussed to facilitate their progression to clinical practice (Graphical Abstract).

Inflammation-Driven Plaque Erosion in Atherosclerosis: A Focus on Complement System Pathways

PURPOSE OF REVIEW

Complement system activation is implicated in various stages of atherogenesis, from fatty streak formation to plaque destabilization and thrombus formation, with its dreadful clinical sequelae such as myocardial infarction, stroke and premature death. In this review, we consider these issues and explore recent studies on complement activation in atherosclerotic plaque initiation and progression.

RECENT FINDINGS

Complement pathways impact plaque stability and healing through the modulation of inflammatory processes. Recent studies indicate that complement components, notably C3 and C5b-9, accelerate atherosclerosis progression through their interactions with endothelial cells, smooth muscle cells, and immune cells. Nonetheless, the beneficial versus deleterious effects of complement activation at different stages of atherogenesis remains a matter of ongoing debates. Research also investigates therapies targeting the complement cascade to mitigate plaque erosion and rupture. This review explores the ongoing debates surrounding complement activation in atherogenesis. We bring forward controversial findings and therapeutic strategies aimed at modulating complement cascade activation with the ultimate goal to reduce the burden of atherosclerotic cardiovascular disease.\.

Neutrophil Hitchhiking-Mediated Delivery of ROS-Scavenging Biomimetic Nanoparticles for Enhanced Treatment of Atherosclerosis

Atherosclerosis (AS), a chronic inflammatory disease and a leading cause of cardiovascular morbidity and mortality worldwide, is a significant contributor to disability. Neutrophil extracellular traps (NETs) have been closely associated with the progression of AS and plaque vulnerability. However, developing a treatment strategy that specifically targets neutrophils and effectively reduces NET release at the lesion site remains a major challenge. In this study, a biomimetic nanosystem with neutrophil-targeting properties is engineered. Coating Prussian blue nanoparticles with bacterial biomimetic membranes (MPB NPs) enables specific recognition and internalization by neutrophils. By hitching onto neutrophils, the MPB NPs scavenge intracellular reactive oxygen species (ROS) and suppress NET formation at the lesion site. Importantly, MPB NPs reduce the size of atherosclerotic plaques by 3.29-fold, from 22.53% to 6.85%, stabilize the plaques, and halt their progression in atherosclerotic mouse models. These findings suggest that MPB NPs offer a promising therapeutic strategy for atherosclerosis, and provide a versatile platform for the treatment of NET-associated diseases.

The roles of neutrophils in cardiovascular diseases

The immune response plays a vital role in the development of cardiovascular diseases (CVDs). As a crucial component of the innate immune system, neutrophils are involved in the initial inflammatory response following cardiovascular injury, thereby inducing subsequent damage and promoting recovery. Neutrophils exert their functional effects in tissues through various mechanisms, including activation and the formation of neutrophil extracellular traps (NETs). Once activated, neutrophils are recruited to the site of injury, where they release inflammatory mediators and cytokines. This study discusses the main mechanisms associated with neutrophil activity and proposes potential new therapeutic targets. In this review, we systematically summarize the diverse phenotypes of neutrophils in disease regulatory mechanisms, different modes of cell death, and focus on the relevance of neutrophils to various CVDs, including atherosclerosis, acute coronary syndrome, myocardial ischemia/reperfusion injury, hypertension, atrial fibrillation, heart failure, and viral myocarditis. Finally, we also emphasize the preclinical/clinical translational significance of neutrophil-targeted strategies.

Neutrophil Extracellular Traps in Atherosclerosis: Research Progress

Atherosclerosis (AS) is a disease characterised by the accumulation of atherosclerotic plaques on the inner walls of blood vessels, resulting in their narrowing. In its early stages, atherosclerosis remains asymptomatic and undetectable by conventional pathological methods. However, as the disease progresses, it can lead to a series of cardiovascular diseases, which are a leading cause of mortality among middle-aged and elderly populations worldwide. Neutrophil extracellular traps (NETs) are composed of chromatin and granular proteins released by neutrophils. Upon activation by external stimuli, neutrophils undergo a series of reactions, resulting in the release of NETs and subsequent cell death, a process termed NETosis. Research has demonstrated that NETosis is a means by which neutrophils contribute to immune responses. However, studies on neutrophil extracellular traps have identified NETs as the primary cause of various inflammation-induced diseases, including cystic fibrosis, systemic lupus erythematosus, and rheumatoid arthritis. Consequently, the present review will concentrate on the impact of neutrophil extracellular traps on atherosclerosis formation, analysing it from a molecular biology perspective. This will involve a systematic dissection of their proteomic components and signal pathways.

Hypothesis on the role of cholesterol crystals in spontaneously ruptured aortic plaques: Potential triggers for inflammation and systemic effects

Cholesterol crystals (CCs) are a key component of atherosclerotic plaques and play a pivotal role in plaque progression, rupture, and the resulting inflammatory responses. CCs emboli trigger proinflammatory cytokines which can potentially lead to organ damage. Spontaneously ruptured aortic plaques (SRAPs) are frequently observed via non-obstructive general angioscopy (NOGA) in patients with or suspected coronary artery disease. The release of CCs from SRAPs can activate the innate immune system and induce neutrophil extracellular trap (NET) formation, further exacerbating inflammation. Inflammation levels in SRAPs vary, and the interleukin (IL)-6 ratio may reflect the degree of inflammation. Systemic inflammation induced by CCs may contribute to conditions that may lead to cerebral infarction, and chronic kidney disease. The effects of anti-inflammatory drugs, including IL-6 inhibitors, IL-1β inhibitors, and colchicine, may be evaluated by measuring the IL-6 ratio in SRAPs. This review examined innate immunity mechanisms associated with CCs in SRAPs sampled via NOGA and discussed their systemic impact and potential therapeutic strategies.

Neutrophil extracellular traps promote MASH fibrosis by metabolic reprogramming of HSC

BACKGROUND AND AIMS

Metabolic dysfunction-associated steatohepatitis (MASH) fibrosis is a reversible stage of liver disease accompanied by inflammatory cell infiltration. Neutrophils extrude a meshwork of chromatin fibers to establish neutrophil extracellular traps (NETs), which play important roles in inflammatory response regulation. Our previous work demonstrated that NETs promote HCC in MASH. However, it is still unknown if NETs play a role in the molecular mechanisms of liver fibrosis.

APPROACH AND RESULTS

Following 12 weeks of Western diet/carbon tetrachloride, MASH fibrosis was identified in C57BL/6 mice with increased NET formation. However, NET depletion using DNase I treatment or mice knocked out for peptidyl arginine deaminase type IV significantly attenuated the development of MASH fibrosis. NETs were demonstrated to induce HSCs activation, proliferation, and migration through augmented mitochondrial and aerobic glycolysis to provide additional bioenergetic and biosynthetic supplies. Metabolomic analysis revealed markedly an altered metabolic profile upon NET stimulation of HSCs that were dependent on arachidonic acid metabolism. Mechanistically, NET stimulation of toll-like receptor 3 induced cyclooxygenase-2 activation and prostaglandin E2 production with subsequent HSC activation and liver fibrosis. Inhibiting cyclooxygenase-2 with celecoxib reduced fibrosis in our MASH model.

CONCLUSIONS

Our findings implicate NETs playing a critical role in the development of MASH hepatic fibrosis by inducing metabolic reprogramming of HSCs through the toll-like receptor 3/cyclooxygenase-2/cyclooxygenase-2 pathway. Therefore, NET inhibition may represent an attractive treatment target for MASH liver fibrosis.

Nanocapsuled Neutrophil Extracellular Trap Scavenger Combating Chronic Infectious Bone Destruction Diseases

Chronic infectious bone destruction diseases, such as periodontitis, pose a significant global health challenge. Repairing the bone loss caused by these chronic infections remains challenging. In addition to pathogen removal, regulating host immunity is imperative. The retention of neutrophil extracellular traps (NETs) in chronic infectious niches is found to be a barrier to inflammation resolution. However, whether ruining the existing NETs within the local infectious bone lesions can contribute to inflammation resolve and bone repair remains understudied. Herein, a nanocapsuled delivery system that scavenges NETs dual-responsively to near-infrared light as a switch and to NETs themselves as a microenvironment sensor is designed. Besides, the photothermal and photodynamic effects endow the nanocapsules with antibacterial properties. Together with the ability to clear NETs, these features facilitate the restoration of the normal host response. The immunocorrective properties and inherent pro-osteogenic effects finally promote local bone repair. Together, the NET scavenging nanocapsules address the challenge of impaired bone repair in chronic infections due to biased host response caused by excessive NETs. This study provides new concepts and strategies for repairing bone destruction attributable to chronic infections via correcting biased host responses in chronic infectious diseases.

NLRP3 inflammasome in cardiovascular diseases: an update

Cardiovascular disease (CVD) continues to be the leading cause of mortality worldwide. The nucleotide oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is involved in numerous types of CVD. As part of innate immunity, the NLRP3 inflammasome plays a vital role, requiring priming and activation signals to trigger inflammation. The NLRP3 inflammasome leads both to the release of IL-1 family cytokines and to a distinct form of programmed cell death called pyroptosis. Inflammation related to CVD has been extensively investigated in relation to the NLRP3 inflammasome. In this review, we describe the pathways triggering NLRP3 priming and activation and discuss its pathogenic effects on CVD. This study also provides an overview of potential therapeutic approaches targeting the NLRP3 inflammasome.

Neutrophils: Linking Inflammation to Thrombosis and Unlocking New Treatment Horizons

Neutrophils play a key role in inflammatory responses and thrombosis, but their complex interactions in disease pathogenesis are not fully understood. This review examines the multifaceted roles of neutrophils, focusing on their activation, cytokine release, and formation of neutrophil extracellular traps (NETs), which contribute to host defense and thrombosis. We discuss the interaction between inflammation and coagulation, the direct effect of neutrophils on thrombus stability, and their involvement in pathological thrombotic diseases. The therapeutic potential of neutrophil drug loading in the treatment of thrombosis, as well as the clinical implications and future research directions, are highlighted. The aim of this review is to gain insight into the critical neutrophil-inflammation-thrombus axis and its potential as a therapeutic target for thrombotic diseases and to suggest possible directions for neutrophil-loaded drug therapy for thrombosis.

Anti-inflammatory Therapies for Ischemic Heart Disease

PURPOSE OF REVIEW

The inclusion of immunomodulatory strategies as supportive therapies in ischemic heart disease (IHD) has garnered significant support over recent years. Several such approaches appear to be unified through their ultimate target, the NLRP3 inflammasome. This review presents a brief update on immunomodulatory strategies in the continuum of conditions constituting ischemic heart disease and emphasising on the seemingly unifying mechanism of NLRP3 activation as well as modulation across these conditions.

RECENT FINDINGS

The NLRP3 inflammasome is a multiprotein complex assembled upon inflammatory stimulation, causing the release of pro-inflammatory cytokines and initiating pyroptosis. The NLRP3 pathway is relevant in inflammatory signalling of cardiac immune cells as well as non-immune cells in the myocardium, including cardiomyocytes, fibroblasts and endothelial cells. In addition to a focus on clinical outcome and efficacy trials of targeting NLRP3-related pathways, the potential connection between immunomodulation in cardiology and the NLRP3 pathway is currently being explored in preclinical trials. Colchicine, cytokine-based approaches and SGLT2 inhibitors have emerged as promising agents. However, the conditions comprising IHD including atherosclerosis, coronary artery disease (CAD), myocardial infarction (MI) and ischemic cardiomyopathy/heart failure (iCMP/HF) are not equally amenable to immunomodulation with the respective drugs. Atherosclerosis, coronary artery disease and ischemic cardiomyopathy are affected by chronic inflammation, but the immunomodulatory approach to acute inflammation in the post-MI setting remains a pharmacological challenge, as detrimental and regenerative effects of myocardial inflammation are initiated in unison. The NLRP3 inflammasome lies at the center of cell mediated inflammation in IHD. Recent trial evidence has highlighted anti-inflammatory effects of colchicine, interleukin-based therapy as well as SGLT2i in IHD and that the respective drugs modulate the NLRP3 inflammasome.

Innovative nanoparticle-based approaches for modulating neutrophil extracellular traps in diseases: from mechanisms to therapeutics

Neutrophil extracellular traps (NETs) participate in both host defense and the pathogenesis of various diseases, such as infections, thrombosis, and tumors. While they help capture and eliminate pathogens, NETs' excessive or dysregulated formation can lead to tissue damage and disease progression. Therapeutic strategies targeting NET modulation have shown potential, but challenges remain, particularly in achieving precise drug delivery and maintaining drug stability. Nanoparticle (NP)-based drug delivery systems offer innovative solutions for overcoming the limitations of conventional therapies. This review explores the biological mechanisms of NET formation, their interactions with NPs, and the therapeutic applications of NP-based drug delivery systems for modulating NETs. We discuss how NPs can be designed to either promote or inhibit NET formation and provide a comprehensive analysis of their potential in treating NET-related diseases. Additionally, we address the current challenges and future prospects for NP-based therapies in NET research, aiming to bridge the gap between nanotechnology and NET modulation for the development of novel therapeutic approaches.

Cytokine signalling in formation of neutrophil extracellular traps: Implications for health and diseases

Neutrophils, as essential component of the innate immune response, form a crucial part in the defence mechanisms through the release of extracellular traps (NETs). These web-like structures, composed of chromatin and antimicrobial proteins, are essential for the entrapment and inactivation of pathogens. However, either constitutive formation or inefficient clearance of NETs leads to adverse effects such as fibrosis, thrombosis, delayed wound healing and tissue damage in multiple diseases associated with sterile inflammation. This dichotomy casts NETs as both protective agents and harmful factors in several diseases such as autoimmune diseases, metabolic syndromes, systemic infections, and malignancies. Besides microbes and their products, variety of stimulants including pro-inflammatory cytokines induce NETs. The complex interactions and cross talk among the pro-inflammatory cytokines including IL-8, IL-6, GM-CSF, TNF-α, IFNs, and IL-1β activate neutrophils to form NETs and also contributes to a vicious circle of inflammatory cascade, leading to increased inflammation, oxidative stress, and thrombotic events. Emerging evidence indicates that the dysregulated cytokine milieus in diseases, such as diabetes mellitus, obesity, atherosclerosis, stroke, rheumatoid arthritis, and systemic lupus erythematosus, potentiate NETs release, thereby promoting disease development. Thus, neutrophils represent both critical effectors and potential therapeutic targets, underscoring their importance in the context of cytokine-mediated therapies for a spectrum of diseases. In the present review, we describe various cytokines and associated signalling pathways activating NETs formation in different human pathologies. Further, the review identifies potential strategies to pharmacologically modulate cytokine pathways to reduce NETs.

Neutrophil heterogeneity and plasticity: unveiling the multifaceted roles in health and disease

Neutrophils, the most abundant circulating leukocytes, have long been recognized as key players in innate immunity and inflammation. However, recent discoveries unveil their remarkable heterogeneity and plasticity, challenging the traditional view of neutrophils as a homogeneous population with a limited functional repertoire. Advances in single-cell technologies and functional assays have revealed distinct neutrophil subsets with diverse phenotypes and functions and their ability to adapt to microenvironmental cues. This review provides a comprehensive overview of the multidimensional landscape of neutrophil heterogeneity, discussing the various axes along which diversity manifests, including maturation state, density, surface marker expression, and functional polarization. We highlight the molecular mechanisms underpinning neutrophil plasticity, focusing on the complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications that shape neutrophil responses. Furthermore, we explore the implications of neutrophil heterogeneity and plasticity in physiological processes and pathological conditions, including host defense, inflammation, tissue repair, and cancer. By integrating insights from cutting-edge research, this review aims to provide a framework for understanding the multifaceted roles of neutrophils and their potential as therapeutic targets in a wide range of diseases.

Inhibition of peptidyl arginine deiminase-4 ameliorated pulmonary fibrosis via modulating M1/M2 polarisation of macrophages

Pulmonary fibrosis (PF) arises from dysregulated wound healing, leading to excessive extracellular matrix (ECM) deposition and impaired lung function. Macrophages exhibit high plasticity, polarizing to pro-inflammatory M1 during early inflammation and anti-inflammatory, fibrosis-inducing M2 during later stages of PF. Additionally, neutrophils and neutrophil extracellular traps (NETs) release mediated by peptidyl arginine deiminase (PAD-4), also play a key role in PF progression. PAD-4 inhibitor chloro-amidine (CLA) has shown anti-fibrotic effects in bleomycin (BLM) induced PF mouse model in our earlier study. Here, we have demonstrated that CLA also exhibited inhibition of macrophage polarisation in in-vitro in THP-1 monocytes and in-vivo in BLM induced PF. THP-1 monocytes were exposed to NETs isolated from phorbol 12-myristate-13-acetate (PMA) stimulated and PMA plus CLA treated differentiated HL-60 (dHL-60) cells. Monocytes exposed to stimulated NETs resulted in increased oxidative stress, disrupted mitochondrial membrane potential and increased M1 and M2 macrophage markers. These alterations were abrogated in THP-1 cells upon exposure to CLA treated NETs. Further, CLA treatment in BLM induced mice improved abnormal BALF, biochemical, and histological parameters in line with our previous findings. Additionally, CLA also reduced M1 and M2 markers time-dependently, as shown by immunofluorescence (IF), western blot, and RT-PCR analysis. CLA treatment led to decreased expression of PAD-4, M1-related pro-inflammatory cytokines and M2-related pro-fibrotic cytokines and mediators, as confirmed by western blot and ELISA analysis. Thus, it is established that inhibition of PAD-4 lead to mitigation of macrophage polarisation and a combined anti-fibrotic effect is achieved which can be explored further.

Unraveling the priming phase of NLRP3 inflammasome activation: Molecular insights and clinical relevance

The NLRP3 inflammasome plays a pivotal role in the innate immune response. Its activation involves a two-step mechanism that consists of priming and activation. The priming of the NLRP3 inflammasome is a vital initial phase necessary for its activation and subsequent involvement in the immune response, though its understanding varies across studies. Recent research has identified key proteins that influence the priming process, revealing a sophisticated regulatory network. This review provides a comprehensive review of the priming phase of NLRP3 inflammasome activation, with a particular focus on the underlying molecular mechanisms, including transcriptional regulation, orchestration of the phosphorylation status, deubiquitination and the relationships with the inflammation-associated diseases. Understanding the intricacies of NLRP3 inflammasome priming not only elucidates fundamental aspects of immune regulation, but also provides potential avenues for therapeutic intervention in inflammatory diseases.

Pathogenic and Protective Roles of Neutrophils in Chlamydia trachomatis Infection

Chlamydia trachomatis (Ct) is an obligate intracellular pathogen that causes the most commonly diagnosed bacterial sexually transmitted infection (STI) and is a leading cause of preventable blindness globally. Ct infections can generate a strong pro-inflammatory immune response, leading to immune-mediated pathology in infected tissues. Neutrophils play an important role in mediating both pathology and protection during infection. Excessive neutrophil activation, migration, and survival are associated with host tissue damage during Chlamydia infections. In contrast, neutrophils also perform phagocytic killing of Chlamydia in the presence of IFN-γ and anti-Chlamydia antibodies. Neutrophil extracellular traps (NETs) and many neutrophil degranulation products have also demonstrated strong anti-Chlamydia functions. To counteract this neutrophil-mediated protection, Chlamydia has developed several evasion strategies. Various Chlamydia proteins can limit potentially protective neutrophil responses by directly targeting receptors present on the surface of neutrophils or neutrophil degranulation products. In this review, we provide a survey of current knowledge regarding the role of neutrophils in pathogenesis and protection, including the ways that Chlamydia circumvents neutrophil functions, and we propose critical areas for future research.

FPR1 affects acute rejection in kidney transplantation by regulating iron metabolism in neutrophils

BACKGROUND

Acute rejection (AR) is one of the significant factors contributing to poor prognosis in patients following kidney transplantation. Neutrophils are the main cause of early host-induced tissue injury. This paper intends to investigate the possible mechanisms of neutrophil involvement in acute rejection in renal transplantation.

METHODS

Samples were analyzed for their relationship with immune cells using CIBERSORT. WGCNA was used to identify modules with high relevance to neutrophils and hub genes in the modules were extracted. The effect on neutrophil function after blocking formyl peptide receptor 1 (FPR1) was tested in vitro experiments. The effects of blocking FPR1 on neutrophil function as well as acute rejection were tested in vivo after constructing a mouse kidney transplant model.

RESULTS

The proportion of neutrophils was higher in the AR group than in the non-rejection group, and FPR1 was identified as an important gene in the regulation of acute rejection in kidney transplantation by neutrophils. At the cellular level, blocking FPR1 inhibited the activation of the ERK1/2 pathway, decreased ferrous ion content, affected the expression of iron metabolism-related proteins, and suppressed the formation of NETs. In the acute rejection model of renal transplantation, blockade of FPR1 decreased graft neutrophil infiltration and NETs content. Meanwhile, blocking FPR1 attenuated graft injury during acute rejection.

CONCLUSION

This study found that FPR1 might be an important molecule involved in neutrophils during acute rejection of kidney transplantation, explored the relationship between kidney transplantation and neutrophils, and provided potential treatment methods for clinical practice.

Pathophysiological Role of Neutrophil Extracellular Traps in Diet-Induced Obesity and Metabolic Syndrome in Animal Models

The global pandemic of obesity poses a serious health, social, and economic burden. Patients living with obesity are at an increased risk of developing noncommunicable diseases or to die prematurely. Obesity is a state of chronic low-grade inflammation. Neutrophils are first to be recruited to sites of inflammation, where they contribute to host defense via phagocytosis, degranulation, and extrusion of neutrophil extracellular traps (NETs). NETs are web-like DNA structures of nuclear or mitochondrial DNA associated with cytosolic antimicrobial proteins. The primary function of NETosis is preventing the dissemination of pathogens. However, neutrophils may occasionally misidentify host molecules as danger-associated molecular patterns, triggering NET formation. This can lead to further recruitment of neutrophils, resulting in propagation and a vicious cycle of persistent systemic inflammation. This scenario may occur when neutrophils infiltrate expanded obese adipose tissue. Thus, NETosis is implicated in the pathophysiology of autoimmune and metabolic disorders, including obesity. This review explores the role of NETosis in obesity and two obesity-associated conditions-hypertension and liver steatosis. With the rising prevalence of obesity driving research into its pathophysiology, particularly through diet-induced obesity models in rodents, we discuss insights gained from both human and animal studies. Additionally, we highlight the potential offered by rodent models and the opportunities presented by genetically modified mouse strains for advancing our understanding of obesity-related inflammation.

Role of Neutrophil Extracellular Traps in Hypertension and Their Impact on Target Organs

Hypertension is the predominant cause of cardiovascular diseases (CVDs) globally, and essential hypertension (EH) represents a significant public health challenge due to its multifactorial etiology involving complex interactions between genetic and environmental factors. However, the pathogenesis of EH is still unclear. Hypertension is a dysregulation in the renin-angiotensin-aldosterone system and sympathetic nervous system, both regulating saline homeostasis and cardiovascular function. However, current therapeutic interventions targeting these systems have limited efficacy in approximately 40% of cases, suggesting the involvement of alternative mechanisms. Inflammation is associated with the occurrence and progression of hypertension, but the underlying mechanism remains elusive, while chronic inflammation leads to tissue damage, fibrosis, and irreversible organ dysfunction. The development and maintenance of EH are caused by endothelial dysfunction, oxidative stress, and chronic inflammation. Neutrophils are involved in both acute and chronic inflammation since they represent the primary line of defense against inflammatory insults once recruited to the inflamed site where they remove harmful impurities. The process involving the formation of neutrophil extracellular traps (NETs) is called NETosis are involved in the pathogenesis and progression of CVDs, including coronary artery disease, acute myocardial infarction, peripheral arterial disease, heart failure, and atrial fibrillation. Recent investigations demonstrated that NETs facilitate the development of hypertension; however, the precise role of NETs in hypertension remains largely elusive. Therefore, this review aims to provide an overview of the current understanding regarding the involvement of NETosis in hypertension and explore the potential therapies targeting NETs for future interventions.

Hypercholesterolemia and inflammation-Cooperative cardiovascular risk factors

BACKGROUND

Maintaining low concentrations of plasma low-density lipoprotein cholesterol (LDLc) over time decreases the number of LDL particles trapped within the artery wall, slows the progression of atherosclerosis and delays the age at which mature atherosclerotic plaques develop. This substantially reduces the lifetime risk of atherosclerotic cardiovascular disease (ASCVD) events. In this context, plaque development and vulnerability result not only from lipid accumulation but also from inflammation.

RESULTS

Changes in the composition of immune cells, including macrophages, dendritic cells, T cells, B cells, mast cells and neutrophils, along with altered cytokine and chemokine release, disrupt the equilibrium between inflammation and anti-inflammatory mechanisms at plaque sites. Considering that it is not a competition between LDLc and inflammation, but instead that they are partners in crime, the present narrative review aims to give an overview of the main inflammatory molecular pathways linked to raised LDLc concentrations and to describe the impact of lipid-lowering approaches on the inflammatory and lipid burden. Although remarkable changes in LDLc are driven by the most recent lipid lowering combinations, the relative reduction in plasma C-reactive protein appears to be independent of the magnitude of LDLc lowering.

CONCLUSION

Identifying clinical biomarkers of inflammation (e.g. interleukin-6) and possible targets for therapy holds promise for monitoring and reducing the ASCVD burden in suitable patients.

Guizhi Shaoyao Zhimu decoction inhibits neutrophil extracellular traps formation to relieve rheumatoid arthritis via gut microbial outer membrane vesicles

BACKGROUND

Rheumatoid arthritis (RA) is a common autoimmune disease with a high disability rate. Accumulating studies suggest that neutrophil extracellular traps (NETs) play a crucial role in the pathogenesis of RA and targeting NETs has emerged as a potential therapeutic strategy for RA. As a traditional Chinese medicine, Guizhi-Shaoyao-Zhimu Decoction (GSZD) has exhibited good efficacy in the treatment of rheumatoid arthritis (RA), while the underly mechanism especially the possibility that GSZD alter NETs formation to relieve RA remains unknown.

PURPOSE

Our study aimed to investigate relationship between GSZD and NETs in RA treatment and revealed underlying mechanism.

METHODS

We constructed collagen-induced arthritis (CIA) model and treated CIA mice with GZSY to validate therapeutic effects of GSZD and examine whether GZSD could inhibit NETs formation in RA. And 16S rRNA sequencing and Fecal microbiota transplantation (FMT) experiment were performed to determine whether GSZD could reduce NETs formation to alleviate RA in gut microbiota-associated manner and identify crucial bacterium in response to GSZD administration. CIA mice treated with effective bacteria and its outer membrane vesicles (OMVs) with oral administration to investigate protective effect against RA and NETs regulative efficiency. We utilized small interfering RNA in vivo and vitro to silence gene mediating effect of GZSD-gut microbiota-NETs.

RESULTS

GSZD could inhibit NETs formation and relive arthritis in CIA mice. Additionally, GSZD alter gut microbiota composition and significantly increase intestinal Parabacteroides goldsteinii (P.goldsteinii) abundance. Mechanistically, P.goldsteinii enriched by GSZD secreted outer membrane vesicles (OMVs) to translocate into joints and activate Cav-1-Nrf2 axis, leading to reduced NETs formation and alleviate arthritis. In clinical, the abundance of P.goldsteinii exhibited negative correlation with NETs indexes and RA disease activities.

CONCLUSION

Our findings suggest that GSZD inhibits NETs formation to relieve RA in P.goldsteinii-Cav-1-Nrf2 associated manner, which could provide new sight of the prevention and treatment of RA.

Integrated multi-omics profiling reveals neutrophil extracellular traps potentiate Aortic dissection progression

Adverse aortic remodeling increases the risk of aorta-related adverse events (AAEs) after thoracic endovascular aortic repair (TEVAR) and affects the overall prognosis of aortic dissection (AD). It is imperative to delve into the exploration of prognostic indicators to streamline the identification of individuals at elevated risk for postoperative AAEs, and therapeutic targets to optimize the efficacy of TEVAR for patients with AD. Here, we perform proteomic and single-cell transcriptomic analyses of peripheral blood and aortic lesions, respectively, from patients with AD and healthy subjects. The integrated multi-omics profiling identifies that highly phenotype-associated macrophages orchestrate neutrophil extracellular traps (NETs) through CXCL3/CXCR2 axis, thereby promoting the development of AD. Increased NETs formation is a defining feature of systemic immunity and aortic microenvironment of AD. Inhibiting NETs formation through the blockade of citrullinated histone H3 or CXCL3/CXCR2 axis ameliorates the progression and rupture of aortic dissection in male mice. The plasma level of citrullinated histone H3 predicts AAEs following endovascular therapy, facilitating the risk stratification and prognostic evaluation for patients with AD.

NET formation-mediated in situ protein delivery to the inflamed central nervous system

Delivering protein drugs to the central nervous system (CNS) is challenging due to the blood-brain and blood-spinal cord barrier. Here we show that neutrophils, which naturally migrate through these barriers to inflamed CNS sites and release neutrophil extracellular traps (NETs), can be leveraged for therapeutic delivery. Tannic acid nanoparticles tethered with anti-Ly6G antibody and interferon-β (aLy6G-IFNβ@TLP) are constructed for targeted neutrophil delivery. These nanoparticles protect interferon-β from reactive oxygen species and preferentially accumulate in neutrophils over other immune cells. Upon encountering inflammation, neutrophils release the nanoparticles during NET formation. In the female mouse model of experimental autoimmune encephalomyelitis, intravenous administration of aLy6G-IFNβ@TLP reduce disease progression and restore motor function. Although this study focuses on IFNβ and autoimmune encephalomyelitis, the concept of hitchhiking neutrophils for CNS delivery and employing NET formation for inflamed site-specific nanoparticle release can be further applied for delivery of other protein drugs in the treatment of neurodegenerative diseases.