Extracellular DNA NET-Works With Dire Consequences for Health

Single-cell sequencing reveals the same heterogeneity of neutrophils in heatstroke-induced lung and liver injury

Heatstroke (HS) is typically considered a sepsis-like syndrome caused by hyperthermia, often accompanied by multiple organ dysfunctions (MODS). To explore the mechanisms of MODS, we established a mouse model of HS by exposing mice to a hyperthermic and high-humidity environment. Then, we utilized single-cell RNA sequencing (scRNA-seq) to depict the cellular landscape of HS mice lung tissue and liver tissue. We found that the enhancement of neutrophil infiltration mediated by the "Cxcr2-Cxcl2″ receptor-ligand pair is a prominent feature of HS-induced lung injury. By effectively suppressing the recruitment of neutrophils in HS-induced lung injury, the application of Cxcr2 inhibitor held positive implications for improving HS-induced lung injury. In addition to the chemotactic effect of immune cells on neutrophils, we identified a subcluster of fibroblasts labeled as Col14a1+, which possessed notable chemotactic factor-secretion characteristics and likely exerted a role in the early stages of neutrophil infiltration. Furthermore, our study unveiled significant heterogeneity among neutrophils within the HS-induced lung injury. Particularly, Cd177 + neutrophils exhibited a dominant presence, characterized by heightened pro-inflammatory responses and oxidative stress. In heatstroke-induced liver injury, neutrophils exhibited similar heterogeneous characteristics. Cd177 + neutrophils exhibited an enhanced ability to produce neutrophil extracellular traps (NETs) while lowering the levels of NETs can significantly improve heatstroke-induced lung and liver injury. Additionally, our study identified Cebpe as a key transcriptional regulatory factor in Cd177 + neutrophil differentiation. Knockdown of the expression of Cebpe can suppress the Cd177 + neutrophil differentiation and decrease the expression levels of NETs. Our research indicated a common heterogeneity in neutrophils during MODS in HS. Cd177 + neutrophils contributed to organ damage in HS, and Cebpe may serve as a crucial intervention target in the treatment of HS.

The role of myeloperoxidase in the pathogenesis of stroke

Stroke is the leading cause of mortality and morbidity worldwide, significantly impacting human welfare and overall health. Myeloperoxidase (MPO), a heme peroxidase secreted by neutrophils, plays a crucial role in the body's defense mechanisms, exhibiting pro-inflammatory and pro-oxidative properties. Additionally, MPO compromises the structural integrity and functional capacity of blood vessels, potentially leading to the formation and dislodgement of atherosclerotic plaques, vascular stenosis, thrombosis, and ultimately contributing to stroke occurrence. Following a stroke, a significant influx of neutrophils infiltrates the cerebral tissue, leading to an excessive release of MPO-derived oxidants and the subsequent promotion of various inflammatory mediators, thereby exacerbating cerebral tissue damage. Numerous studies have consistently demonstrated the pivotal role of MPO in the pathogenesis and progression of stroke, establishing it as a reliable prognostic indicator. Exploring the association between MPO and stroke enhances our understanding of the pathological mechanisms underlying stroke and aids in the development of therapeutic interventions. This review provides a comprehensive analysis of the molecular structure and cellular localization of MPO, elucidating its critical role in mediating vascular injury, the formation of Neutrophil Extracellular Traps (NETs), oxidative stress, neuroinflammation, disruption of the blood-brain barrier (BBB), and neuronal apoptosis during stroke pathogenesis. Additionally, we discuss recent advancements in MPO-targeted drugs and Traditional Chinese Medicine compounds as potential therapeutic strategies for stroke treatment.

Biomaterial-driven 3D scaffolds for immune cell expansion toward personalized immunotherapy

Immunotherapy has emerged as a transformative medical approach in recent years, providing novel treatments for cancer eradication, autoimmune disorders, and infectious diseases. Fundamental to the success of therapy is the enrichment of the immune cell population, particularly T cells, natural killer cells, and dendritic cells. However, achieving a robust and long-term proliferation of immune cells is still challenging both in vivo and ex vivo. In vivo expansion leverages the patient's natural microenvironment and regulatory mechanisms through therapeutic interventions like immune checkpoint inhibitors, cytokine therapy, and targeted antibodies. This approach fosters long-term immune memory and sustained protection. In contrast, ex vivo expansion involves isolation, manipulation, and expansion of the immune cells under controlled conditions before reinfusion, allowing for precise control over the process and generating potent immune cell populations. Hydrogels, due to their tunable biomechanical properties, high biocompatibility, and ability to mimic the extracellular matrix, provide an ideal platform for both in vivo and ex vivo immune cell expansion. For instance, hydrogel-based scaffolds or beads can facilitate a controlled and efficient expansion of immune cells ex vivo, whereas injectable and implantable hydrogels can provide innovative solutions for enhancing immune cell activity within the patient supporting prolonged immune cell activity. This review aims to elucidate the importance of hydrogel-based strategies in immune cell expansion, advancing the development of effective, personalized immunotherapies to improve patient outcomes. STATEMENT OF SIGNIFICANCE: This review highlights the transformative potential of hydrogel-based 3D scaffolds in advancing personalized immunotherapy. By integrating in vivo and ex vivo strategies, hydrogels provide an innovative platform to enhance immune cell expansion, addressing critical challenges in immunotherapy. The discussion emphasizes the unique biomechanical and biochemical tunability of hydrogels, enabling precise mimicry of the extracellular matrix to support T cell proliferation, activation, and memory formation. These advances offer scalable, cost-effective solutions for producing high-quality immune cells, contributing to more effective cancer treatments, autoimmune disease management, and infectious disease control. By bridging materials science and immunology, this work underscores the pivotal role of hydrogels in shaping the future of immune-based therapies.

Novel insights into the association between organ damage and inflammatory response in preoperative abdominal aortic aneurysms

Background

Abdominal aortic aneurysm (AAA) is a life-threatening condition in the elderly population. The insidious nature of AAA onset makes early detection difficult. Currently, there are few studies on changes in laboratory parameters during AAA development.

Methods

This study included 55 elderly patients with AAA who were admitted to the Department of Vascular Medicine, Shougang Hospital, Peking University 2021-2022. Propensity score matching (PSM) in a 1:1 ratio was performed to match the 55 patients and 1,031 controls. In this population of AAA, correlation and regression analyses were used to explore the association between the level of inflammation and each laboratory parameter.

Results

Compared to the control group, significant differences in inflammatory markers, transaminase and bilirubin levels, blood urea nitrogen (BUN) and creatinine (Cr) levels, and ankle-brachial index were found in the aneurysm group. After PSM, the differences between the two groups for each parameter remained statistically significant. Correlation and regression analyses showed a weak positive correlation between the inflammatory index and the BUN and Cr levels (correlation coefficient = 0.22).

Conclusions

Our study demonstrates the presence of a highly inflammatory state and damage to various organs in patients with AAA. This hyperinflammatory state may be associated with kidney injury and is a cause of concern.

Neutrophils induce astrocytic AQP4 expression via IL-1α and TNF, contributing to cerebral oedema in ischaemic stroke rats

During the acute phase (1-3 days) of cerebral infarction, neutrophils and macrophages accumulate at the infarction site, inducing inflammation and cerebral oedema. However, the role of neutrophils in oedema formation after ischaemic stroke remains unclear. This study examined neutrophil involvement in cerebral oedema using a transient middle cerebral artery occlusion (tMCAO) rat model, primary cultured neutrophils, and astrocytes. Brain specimens were stained with myeloperoxidase (MPO) and lymphocyte antigen 6 complexes, locus G (Ly6G), and the number of MPO+/Ly6G+ cells was counted. Neutrophil infiltration began in the leptomeninges at 3 h, reaching the ischaemic cortex by 6 h and the striatum by 24 h, peaking at 24-48 h before declining. Neutrophils attached to endothelial walls and infiltrated the brain parenchyma, correlating with oedema severity. Infiltrating neutrophils strongly expressed IL-1α and TNF in the ischaemic brain. Co-culturing LPS-activated neutrophils with astrocytes increased Aqp4 mRNA and protein expression, which was inhibited by IL-1RI and TNF antagonists. These findings suggest that activated neutrophils exacerbate cerebral oedema by inducing astrocytic AQP4 expression via IL-1α and TNF in peri-infarct and ischaemic core tissues.

Quantification of Circulating Cell-Free DNA as a NETosis Marker in Trauma Patients with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) significantly impairs fracture healing, with neutrophils playing a crucial role in this process. In T2DM, these immune cells are over-activated, leading to the excessive release of neutrophil extracellular traps (NETs), increasing inflammation and hindering recovery. Thus, a need for markers to assess patients in the risk group arises. This study demonstrates that circulating cell-free DNA (cfDNA) can be efficiently quantified from serum samples by a single-step qPCR and be used as a marker for NETosis. Our results revealed that trauma patients with T2DM have the highest cfDNA levels, followed by trauma patients, and the healthy group has the lowest. The method shows strong correlations between cfDNA and neutrophil-specific markers such as MPO, citH3, AZU1, and α-defensin, highlighting its potential as a rapid indicator of NETosis. This approach could allow the timely interference for high-risk patients, ultimately improving healing outcomes and reducing complications such as chronic inflammation, non-union fractures, and diabetic foot ulcers.

Neutrophil-to-lymphocyte ratio predicts a poor prognosis for penile cancer with an immunosuppressive tumor microenvironment

Background

Chronic inflammation related to poor genital hygiene is a well-recognized pathogenic trigger for penile cancer (PC). The neutrophil-to-lymphocyte ratio (NLR) is a simple, reproducible systemic inflammatory marker and has been reported to indicate unfavorable outcomes. However, previous studies were limited by small sample sizes, confounding prognostic factors and a lack of high-quality evidence demonstrating the significance of the NLR in PC.

Methods

A large multicenter cohort of 582 PC patients who underwent radical inguinal lymphadenectomy with definitive pN stage information was assessed. Univariate and multivariate Cox regression analyses were performed to investigate the prognostic value of inflammation-related markers. Propensity score matching (PSM) was used to minimize confounding prognostic clinicopathological features. Immunofluorescence was used to assess the immunosuppressive tumor microenvironment (TME).

Results

A high preoperative NLR (≥ 3.0) was associated with advanced pT, pN, and pathological grade and lymphovascular invasion in PC patients. After PSM to eliminate interference from clinical factors, pN and the NLR were found to be independent prognostic indicators (both p<0.001). PC patients with high NLRs had shorter progression-free survival (PFS) and poorer cisplatin-based chemotherapy and PD-1 immunotherapy response. We also found that the NLR is associated with proinflammatory cytokine secretion and increased N2 tumor-associated neutrophils (TANs) infiltration and CD8+ T-cell exhaustion in TME. N2 TANs induced neutrophil extracellular trap formation might contribute to tumor progression and resistance in high-NLR PC patients.

Conclusions

The NLR is an effective, simple and independent prognostic indicator for PC. A high NLR is associated with an immunosuppressive TME and poor outcomes.

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.

An In Vitro Cell Model of Intestinal Barrier Function Using a Low-Cost 3D-Printed Transwell Device and Paper-Based Cell Membrane

Current in vitro methods for intestinal barrier assessment predominantly utilize two-dimensional (2D) membrane inserts in standard culture plates, which are widely recognized for their inability to replicate the microenvironment critical to intestinal barrier functionality. Our study focuses on creating an alternative method for intestinal barrier function by integrating a 3D-printed transwell device with a paper-based membrane. Caco-2 cells were grown on a Matrigel-modified paper membrane, in which the tight junction formation was evaluated using TEER measurements. Neutrophil-like dHL-60 cells were employed for neutrophil extracellular trap (NET) formation experiments. Furthermore, intestinal barrier dysfunction was demonstrated using NET-isolated and Staurosporine interventions. Intestinal barrier characteristics were investigated through immunofluorescence staining of specific proteins and scanning electron microscopy (SEM). Our paper-based intestinal barrier exhibited an increased resistance in a time-dependent manner, consistent with immunofluorescence images of Zonulin Occludens-1 (ZO-1) expression. Interestingly, immunofluorescence analysis revealed changes in the morphology of the intestinal barrier and the formation of surface villi. These disruptions were found to alter the localization of tight junctions, impacting epithelial polarization and surface functionality. Moreover, we successfully demonstrated the permeability of a paper-based intestinal barrier using FITC-dextran assay. Hence, the 3D-printed transwell device integrated with a paper membrane insert presents a straightforward, cost-effective, and sustainable platform for an in vitro cell model to evaluate intestinal barrier function.

Neutrophil extracellular traps-induced pyroptosis of liver sinusoidal endothelial cells exacerbates intrahepatic coagulation in cholestatic mice

BACKGROUND

Neutrophil extracellular traps (NETs) and NOD-like receptor protein 3 (NLRP3) inflammation are key contributors to cholestatic liver disease (CLD). However, the relationship between NETs release and inflammasome activation, as well as its contribution to intrahepatic coagulation in CLD, remains unexplored. This study explores NETs-induced liver sinusoidal endothelial cells (LSECs) pyroptosis on intrahepatic coagulation in CLD.

METHODS

Wild-type (WT) and PAD4-/- mice underwent bile duct ligation (BDL) or sham surgery for 7 or 14 days. The liver analysis assessed intrahepatic coagulation, inflammation, fibrosis, NETs release, and NLRP3 activation. Primary LSECs were exposed to NETs with or without MCC950. Pyroptosis and LSECs procoagulant activity were quantified.

RESULTS

BDL mice exhibited significantly increased inflammation, tissue factor (TF), and fibrin deposition compared with controls. NETs release in the liver was increased significantly in WT BDL mice and was responsible for intrahepatic coagulation. PAD4 deficiency reduced TF and fibrin expression, improving hepatic sinusoid function. RNA-seq revealed BDL-induced enrichment of coagulation, neutrophil activation, and pyroptosis pathways. In vivo, NETs increased intrahepatic NLRP3 and IL-1β expression in BDL mice. However, NLRP3 inhibition (MCC950) or activation (BMS-986299) did not alter NETs release. Furthermore, NETs-induced NLRP3 activation increased intrahepatic coagulation, inflammation, and fibrosis. Finally, we demonstrated that NETs triggered LSECs dysfunction and pyroptosis, upregulating TF and phosphatidylserine production and enhancing procoagulant activity.

CONCLUSIONS

NETs-induced LSECs pyroptosis exacerbates intrahepatic coagulation in cholestasis. Targeting NETs and LSECs pyroptosis holds promise for treating chronic liver injury in CLD.

Complex regulation of cardiac fibrosis: insights from immune cells and signaling pathways

Cardiac fibrosis is a physiological process that involves the formation of scar tissue in the heart in response to injury or damage. This process is initially a protective measure characterized by enhanced fibroblasts, which are responsible for producing extracellular matrix proteins that provide structural support to the heart. However, when fibrosis becomes excessive, it can lead to adverse outcomes, including increasing tissue stiffness and impaired cardiac function, which can ultimately result in heart failure with a poor prognosis. While fibroblasts are the primary cells involved in cardiac fibrosis, immune cells have also been found to play a vital role in its progression. Recent research has shown that immune cells exert multifaceted effects besides regulation of inflammatory response. Advanced research techniques such as single-cell sequencing and multiomics have provided insights into the specific subsets of immune cells involved in fibrosis and the complex regulation of the process. Targeted immunotherapy against fibrosis is gaining traction as a potential treatment option, but it is still unclear how immune cells achieve this regulation and whether distinct subsets are involved in different roles. To better understand the role of immune cells in cardiac fibrosis, it is essential to examine the classical signaling pathways that are closely related to fibrosis formation. We have also focused on the unique properties of diverse immune cells in cardiac fibrosis and their specific intercommunications. Therefore, this review will delve into the plasticity and heterogeneity of immune cells and their specific roles in cardiac fibrosis, which propose insights to facilitate the development of anti-fibrosis therapeutic strategies.

NINJ1-mediated plasma membrane rupture of pyroptotic endothelial cells exacerbates blood-brain barrier destruction caused by neutrophil extracellular traps in traumatic brain injury

Brain endothelial cell (bEC) dysfunction is the main factor of blood-brain barrier (BBB) breakdown, which triggers a vicious cycle of aggravating traumatic brain injury (TBI) pathogenesis. Previous studies have revealed that neutrophil extracellular traps (NETs) released by neutrophils can lead to BBB disruption, but there is a lack of research on the underlying mechanisms after TBI. Here, excessive NETs were found in both contused brain tissue and circulation following TBI. We found that NETs could activate the TLR4/NF-κB pathway to induce bEC pyroptosis, which led to BBB disruption after TBI. During this process, ninjurin-1 (NINJ1) was activated in pyroptotic bECs, and it mediated the release of high mobility group box 1 protein (HMGB1) via plasma membrane rupture (PMR) to promote NET formation. NINJ1-mediated release of HMGB1 aggravated NET accumulation by forming a vicious circle following TBI. Knockdown of NINJ1 rescued NET formation, attenuated BBB leakage, and improved neurological outcomes after TBI. NINJ1 may represent a promising target for alleviating NET-induced BBB destruction and other related injuries after TBI.

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.

Framework Nucleic Acid-Based and Neutrophil-Based Nanoplatform Loading Baicalin with Targeted Drug Delivery for Anti-Inflammation Treatment

Targeted drug delivery is a promising strategy for treating inflammatory diseases, with recent research focusing on the combination of neutrophils and nanomaterials. In this study, a targeted nanodrug delivery platform (Ac-PGP-tFNA, APT) was developed using tetrahedral framework nucleic acid (tFNA) along with a neutrophil hitchhiking mechanism to achieve precise delivery and anti-inflammatory effects. The tFNA structure, known for its excellent drug-loading capacity and cellular uptake efficiency, was used to carry a therapeutic agent─baicalin. The results demonstrate that the development of this drug delivery platform not only considerably enhances the bioavailability and effective concentration of the drug (baicalin) but also promotes the polarization of pro-inflammatory M1 macrophages to anti-inflammatory M2 macrophages by modulating the interactions between the neutrophils and macrophages. This targeted therapeutic method effectively treats inflammatory conditions such as sepsis and introduces a strategy for managing inflammatory diseases characterized by neutrophil infiltration.

NET burden in left atrial blood is associated with biomarkers of thrombosis and cardiac injury in patients with enlarged left atria

BACKGROUND

Emerging data suggest an association between left atrial (LA) enlargement, thrombus formation, and ischemic stroke. However, it is unknown what may mediate such clot formation in LA dysfunction. Neutrophils promote large vessel occlusion and microthrombosis via neutrophil extracellular trap (NET) release, thus lying at the interface of inflammation, thrombosis, and fibrosis.

APPROACH

We conducted a prospective all-comers cohort study in patients undergoing catheterization procedures with atrial transseptal access (MitraClip, MC; left atrial appendage closure, LAAC; pulmonary vein ablation, PVA; patent foramen ovale closure, PFO). We measured NETs, cytokines, thrombotic factors, and cardiac injury markers in paired blood samples collected from peripheral blood and within the left atrium. We correlated these biomarkers with echocardiographic measures of LA structure and function (including left atrial volume index, LAVI). Data were analyzed by procedure type, and stratified by LAVI or atrial fibrillation (AF) status.

RESULTS

We enrolled 70 patients (mean age 64 years, 53% women). NETs, but not other markers, were elevated in LA compared to peripheral blood samples. Most thrombotic, inflammatory, and cardiac damage markers were elevated in LAs from MC or LAAC compared to PFO patients. Overall, NET biomarkers positively correlated with VWF, LAVI, and markers of cardiac injury and negatively with ADAMTS13 activity. LA enlargement and the presence of AF similarly stratified patients based on thromboinflammation measurements, but this was not limited to AF at the time of sample collection.

CONCLUSION

Elevated NETs and VWF in patients with enlarged LA or AF suggest enhanced thromboinflammation within the LA.

Neutrophil Extracellular Traps Induce Brain Edema Around Intracerebral Hematoma via ERK-Mediated Regulation of MMP9 and AQP4

Perihematomal edema (PHE) significantly aggravates secondary brain injury in patients with intracerebral hemorrhage (ICH), yet its detailed mechanisms remain elusive. Neutrophil extracellular traps (NETs) are known to exacerbate neurological deficits and worsen outcomes after stroke. This study explores the potential role of NETs in the pathogenesis of brain edema following ICH. The rat ICH model was created, immunofluorescence and Western blot were used to examine neutrophil accumulation, NET markers citrullinated histone H3 (CitH3) and myeloperoxidase (MPO), tight junction proteins (ZO-1 and Occludin), Aquaporin-4 (AQP4), matrix metalloproteinase-9 (MMP-9), and ERK phosphorylation (p-ERK) in brain tissues surrounding the hematoma. TUNEL staining and behavioral tests were employed to evaluate neuronal apoptosis and neurological dysfunction, while blood-brain barrier (BBB) permeability and brain edema were also measured by Evans blue and brain water content. Furthermore, the molecular mechanisms related to NETs-induced PHE were investigated using NETs, ERK, MMP-9 and AQP4 regulators, respectively. Ly6G+ neutrophils surrounding the hematoma developed NETs within 3 days post-ICH. NETs decreased tight junction proteins, destroyed BBB integrity, promoted brain edema, increased neuronal apoptosis, and exacerbated neurological deficits. Conversely, inhibition of NETs mitigated PHE, reduced neuronal apoptosis, and improved neurological functions. Mechanistically, NET-induced PHE was originated from impairment of BBB tight junction via ERK/MMP9 pathway, coupled with ERK-mediated AQP4 downregulation in perihematomal regions. These findings elucidated the effects of NETs on PHE, which offered promising insights for targeting NETs to relieve brain edema and secondary brain injury post-ICH.

Advances in molecular imaging and targeted therapeutics for lymph node metastasis in cancer: a comprehensive review

Lymph node metastasis is a critical indicator of cancer progression, profoundly affecting diagnosis, staging, and treatment decisions. This review article delves into the recent advancements in molecular imaging techniques for lymph nodes, which are pivotal for the early detection and staging of cancer. It provides detailed insights into how these techniques are used to visualize and quantify metastatic cancer cells, resident immune cells, and other molecular markers within lymph nodes. Furthermore, the review highlights the development of innovative, lymph node-targeted therapeutic strategies, which represent a significant shift towards more precise and effective cancer treatments. By examining cutting-edge research and emerging technologies, this review offers a comprehensive overview of the current and potential impact of lymph node-centric approaches on cancer diagnosis, staging, and therapy. Through its exploration of these topics, the review aims to illuminate the increasingly sophisticated landscape of cancer management strategies focused on lymph node assessment and intervention.

Endothelial Dysfunction and Cardiovascular Disease: Hyperbaric Oxygen Therapy as an Emerging Therapeutic Modality?

Maintaining the physiological function of the vascular endothelium and endothelial glycocalyx is crucial for the prevention of cardiovascular disease, which is one of the leading causes of morbidity and mortality worldwide. Damage to these structures can lead to atherosclerosis, hypertension, and other cardiovascular problems, especially in individuals with risk factors such as diabetes and obesity. Endothelial dysfunction is associated with ischemic disease and has a negative impact on overall cardiovascular health. The aim of this review was to comprehensively summarize the crucial role of the vascular endothelium and glycocalyx in cardiovascular health and associated thrombo-inflammatory conditions. It highlights how endothelial dysfunction, influenced by factors such as diabetes, chronic kidney disease, and obesity, leads to adverse cardiovascular outcomes, including heart failure. Recent evidence suggests that hyperbaric oxygen therapy (HBOT) may offer therapeutic benefits in the treatment of cardiovascular risk factors and disease. This review presents the current evidence on the mechanisms by which HBOT promotes angiogenesis, shows antimicrobial and immunomodulatory effects, enhances antioxidant defenses, and stimulates stem cell activity. The latest findings on important topics will be presented, including the effects of HBOT on endothelial dysfunction, cardiac function, atherosclerosis, plaque stability, and endothelial integrity. In addition, the role of HBOT in alleviating cardiovascular risk factors such as hypertension, aging, obesity, and glucose metabolism regulation is discussed, along with its impact on inflammation in cardiovascular disease and its potential benefit in ischemia-reperfusion injury. While HBOT demonstrates significant therapeutic potential, the review also addresses potential risks associated with excessive oxidative stress and oxygen toxicity. By combining information on the molecular mechanisms of HBOT and its effects on the maintenance of vascular homeostasis, this review provides valuable insights into the development of innovative therapeutic strategies aimed at protecting and restoring endothelial function to prevent and treat cardiovascular diseases.

Ischemia/reperfusion injury in acute human and experimental stroke: focus on thrombo-inflammatory mechanisms and treatments

BACKGROUND

Despite high recanalization rates of > 90% after endovascular thrombectomy (EVT) clinical outcome in around 50% of treated acute ischemic stroke (AIS) patients is still poor. Novel treatments augmenting the beneficial effects of recanalization are eagerly awaited, but this requires mechanistic insights to explain and overcome futile recanalization.

MAIN BODY

At least two mechanisms contribute to futile recanalization after cerebral large vessel occlusions (LVO): (i) the no reflow phenomenon as evidenced by randomly distributed areas without return of blood flow despite reperfusion of large cerebral arteries, and (ii) ischemia/reperfusion (I/R) injury, the paradoxically harmful aspect of blood flow return in transiently ischemic organs. There is accumulating evidence from experimental stroke models that platelets and leukocytes interact and partly obstruct the microvasculature under LVO, and that platelet-driven inflammation (designated thrombo-inflammation) extends into the reperfusion phase and causes I/R injury. Blocking of platelet glycoprotein receptors (GP) Ib and GPVI ameliorated inflammation and I/R injury providing novel therapeutic options. Recently, MRI studies confirmed a significant, up to 40% infarct expansion after recanalization in AIS thereby proofing the existance of I/R injury in the human brain. Moreover, analysis of minute samples of ischemic arterial blood aspirated directly from the pial cerebral collateral circulation under LVO during the routine EVT procedure confirmed platelet activation and platelet-driven leukocyte accumulation in AIS and, thus, the principal transferability of pathophysiological stroke mechanisms from rodents to man. Two recently published clinical phase 1b/2a trials targeted (thrombo-) inflammation in AIS: The ACTIMIS trial targeting platelet GPVI by glenzocimab provided encouraging safety signals in AIS similar to the ApTOLL trial targeting toll-like receptor 4, a central receptor guiding stroke-induced innate immunity. However, both studies were not powered to show clinical efficacy.

CONCLUSIONS

The fact that the significance of I/R injury in AIS has recently been formally established and given the decisive role of platelet-leukocytes interactions herein, new avenues for adjunct stroke treatments emerge. Adjusted study designs to increase the probability of success are of outmost importance and we look forward from what can be learned from the so far unpublished, presumbably negative ACTISAFE and MOST trials.

Impact of Protein Citrullination by Periodontal Pathobionts on Oral and Systemic Health: A Systematic Review of Preclinical and Clinical Studies

Background: This review synthesizes the role of Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in modulating immune responses through citrullination and assesses its impact on periodontitis and systemic conditions. Methods: A systematic review was conducted on preclinical and clinical studies focusing on P. gingivalis- and A. actinomycetemcomitans-induced citrullination and its effects on immune responses, particularly inflammatory pathways, and systemic diseases. The search included PubMed, Scopus, Google Scholar, Web of Science, and gray literature. Quality and risk of bias were assessed using OHAT Rob Toll and QUIN-Tool. The review is registered in PROSPERO (ID: CRD42024579352). Results: 18 articles published up to August 2024 were included. Findings show that P. gingivalis and A. actinomycetemcomitans citrullination modulates immune responses, leading to neutrophil dysfunction and chronic inflammation. Key mechanisms include citrullination of antimicrobial peptides, CXCL10, histone H3, α-enolase, and C5a, impairing neutrophil activation and promoting NET formation. Conclusions: This review suggests that P. gingivalis and A. actinomycetemcomitans citrullination modulates immune responses and may influence periodontitis and systemic conditions like RA. Beyond ACPA production, these pathogens affect key proteins such as H3, C5a, and CXCL10, as well as antimicrobial peptides, NET formation, and phagocytosis. These interactions lead to neutrophil dysfunction and potentially affect other cells, subsequently disrupting local and systemic inflammatory responses.

Nucleic acid liquid biopsies in cardiovascular disease: Cell-free DNA liquid biopsies in cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death worldwide, and despite treatment efforts, cardiovascular function cannot always be restored, and progression of disease be prevented. Critical insights are oftentimes based on tissue samples. Current knowledge of tissue pathology typically relies on invasive biopsies or postmortem samples. Liquid biopsies, which assess circulating mediators to deduce the histology and pathology of distant tissues, have been advancing rapidly in cancer research and offer a promising approach to be translated to the understanding and treatment of CVD. The widely understood elevations in cell-free DNA during acute and chronic cardiovascular conditions, associate with disease, severity, and offer prognostic value. The role of neutrophil extracellular traps (NETs) and circulating nucleases in thrombosis provide a solid rationale for liquid biopsies in CVD. cfDNA originates from various tissue types and cellular sources, including mitochondria and nuclei, and can be used to trace cell and tissue type lineage, as well as to gain insight into the activation status of cells. This article discusses the origin, structure, and potential utility of cfDNA, offering a deeper and less invasive approach for the understanding of the complexities of CVD.

The Crucial Triad: Endothelial Glycocalyx, Oxidative Stress, and Inflammation in Cardiac Surgery-Exploring the Molecular Connections

Since its introduction, the number of heart surgeries has risen continuously. It is a high-risk procedure, usually involving cardiopulmonary bypass, which is associated with an inflammatory reaction that can lead to perioperative and postoperative organ dysfunction. The extent of complications following cardiac surgery has been the focus of interest for several years because of their impact on patient outcomes. Recently, numerous scientific efforts have been made to uncover the complex mechanisms of interaction between inflammation, oxidative stress, and endothelial dysfunction that occur after cardiac surgery. Numerous factors, such as surgical and anesthetic techniques, hypervolemia and hypovolemia, hypothermia, and various drugs used during cardiac surgery trigger the development of systemic inflammatory response and the release of oxidative species. They affect the endothelium, especially endothelial glycocalyx (EG), a thin surface endothelial layer responsible for vascular hemostasis, its permeability and the interaction between leukocytes and endothelium. This review highlights the current knowledge of the molecular mechanisms involved in endothelial dysfunction, particularly in the degradation of EG. In addition, the major inflammatory events and oxidative stress responses that occur in cardiac surgery, their interaction with EG, and the clinical implications of these events have been summarized and discussed in detail. A better understanding of the complex molecular mechanisms underlying cardiac surgery, leading to endothelial dysfunction, is needed to improve patient management during and after surgery and to develop effective strategies to prevent adverse outcomes that complicate recovery.

The pivotal role of neutrophil extracellular traps in cardiovascular diseases: Mechanisms and therapeutic implications

Cardiovascular diseases (CVDs) continue to pose a significant burden on global health, prominently contributing to morbidity and mortality rates worldwide. Recent years have witnessed an increasing recognition of the intricate involvement of neutrophil extracellular traps (NETs) in the pathology of diverse cardiovascular conditions. This review provides a comprehensive analysis of the multifaceted functions of NETs in cardiovascular diseases, shedding light on the impact on atherosclerosis, myocardial infarction, heart failure, myocarditis, atrial fibrillation, aortic stenosis, and the potential therapeutic avenues targeting NETs.

Neutrophil extracellular traps and citrullinated fibrinogen contribute to injury in a porcine model of limb ischemia and reperfusion

Background

Ischemia/reperfusion injury (IRI) is a complex pathological process, triggered by the restoration of blood flow following an interrupted blood supply. While restoring the blood flow is the only option to salvage the ischemic tissue, reperfusion after a prolonged period of ischemia initiates IRI, triggering a cascade of inflammatory responses ultimately leading to neutrophil recruitment to the inflamed tissue, where they release neutrophil extracellular traps (NETs). NETs are web-like structures of decondensed chromatin and neutrophilic proteins, including peptidyl-arginine deiminase 2 and 4 (PAD2, PAD4), that, once outside, can citrullinate plasma proteins, irreversibly changing their conformation and potentially their function. While the involvement of NETs in IRI is known mainly from rodent models, we aimed to determine the effect of NET formation and especially PADs-mediated extracellular protein citrullination in a porcine model of limb IRI.

Methods

We conducted our study on amputated pig forelimbs exposed to 1 h or 9 h of ischemia and then reperfused in vivo for 12 h. Limb weight, edema formation, compartmental pressure were measured, and skeletal muscle was analyzed by immunofluorescence (TUNEL assay and dystrophin staining) to evaluate tissue damage. Fibrin tissue deposition, complement deposition and NETs were investigated by immunofluorescence. Citrullinated plasma proteins were immunoprecipitated and citrullinated fibrinogen was identified in the plasma by Western blot and in the tissue by immunofluorescence and Western blot.

Results

Our data consolidate the involvement of NETs in a porcine model of limb IRI, correlating their contribution to damage extension with the duration of the ischemic time. We found a massive infiltration of NETs in the group subjected to 9 h ischemia compared to the 1 h and citrullinated fibrinogen levels, in plasma and tissue, were higher in 9 h ischemia group. We propose fibrinogen citrullination as one of the mechanisms contributing to the worsening of IRI. NETs and protein citrullination represent a potential therapeutic target, but approaches are still a matter of debate. Here we introduce the idea of therapeutic approaches against citrullination to specifically inhibit PADs extracellularly, avoiding the downstream effects of hypercitrullination and keeping PADs' and NETs' intracellular regulatory functions.

Neutrophil Extracellular Trap Formation in Advanced Heart Failure Patients-Preliminary Report

In end-stage heart failure, which is characterized by persistent or progressive ventricular dysfunction despite optimal medical therapy, a left ventricular assist device (LVAD) can be beneficial. Congestive heart failure provokes inflammatory and prothrombotic activation. The aim of this study was to evaluate the serum concentration of citrullinated histone 3 (CH3) representing neutrophil extracellular trap (NET) formation in patients referred for LVAD implantation. There were 10 patients with a median age of 61 (57-65) years enrolled in a prospective single-center analysis who underwent LVAD implantation. The CH3 plasma concentration was measured preoperatively and on the 1st and 7th postoperative days, followed by control measurements on the median (Q1-3) 88th (49-143) day. The preoperative CH3 concentration strongly correlated with brain natriuretic peptide (r = 0.879, p < 0.001). Significant differences in CH3 serum concentration were observed between pre- and postoperative measurements, including an increase on the first postoperative day (p < 0.001), as well as a decrease on the seventh day (p = 0.016) and in follow-up (p < 0.001). CH3 concentration, as a marker of NET formation, decreases after LVAD implantation.

The clonal hematopoiesis mutation Jak2V617F aggravates endothelial injury and thrombosis in arteries with erosion-like intimas

BACKGROUND

Superficial plaque erosion causes many acute coronary syndromes. However, mechanisms of plaque erosion remain poorly understood, and we lack directed therapeutics for thrombotic complication. Human eroded plaques can harbor neutrophil extracellular traps (NETs) that propagate endothelial damage at experimental arterial lesions that recapitulate superficial erosion. Clonal Hematopoiesis of Indeterminate Potential (CHIP) denotes age-related clonal expansion of bone marrow-derived cells harboring somatic mutations in the absence of overt hematological disease. CHIP heightens the risk of cardiovascular disease, with the greatest increase seen in individuals with JAK2V617F. Neutrophils from mice and humans with JAK2V617F undergo NETosis more readily than Jak2WT (wild-type) cells. We hypothesized that JAK2V617F, by increasing propensity to NETosis, exacerbates aspects of superficial erosion.

METHODS AND RESULTS

We generated Jak2V617F and Jak2WT mice with heterozygous Jak2V617F in myeloid cells. We induced areas of denuded endothelium that recapitulate features of superficial erosion and assessed endothelial integrity, cellular composition of the erosion, thrombosis rates, and response to ruxolitinib, a clinically available JAK1/2 inhibitor, in relation to genotype. Following experimental erosion, Jak2V617F mice have greater impairment of endothelial barrier function and increased rates of arterial thrombosis. Neointimas in Jak2V617F mice exhibit increased apoptosis, NETosis, and platelet recruitment. Jak2V617F mice treated with ruxolitinib show increased endothelial continuity and reduced apoptosis in the neointima comparable to levels in Jak2WT.

CONCLUSIONS

These observations provide new mechanistic insight into the pathophysiology of superficial erosion, the heightened risk for myocardial infarction in JAK2V617F CHIP, and point the way to personalized therapeutics based on CHIP status.

Neutrophil extracellular traps in cancer

Neutrophil extracellular traps (NETs), which consist of chromatin DNA studded with granule proteins, are released by neutrophils in response to both infectious and sterile inflammation. Beyond the canonical role in defense against pathogens, the extrusion of NETs also contributes to the initiation, metastasis, and therapeutic response of malignant diseases. Recently, NETs have been implicated in the development and therapeutic responses of various types of tumors. Although extensive work regarding inflammation in tumors has been reported, a comprehensive summary of how these web-like extracellular structures initiate and propagate tumor progression under the specific microenvironment is lacking. In this review, we demonstrate the initiators and related signaling pathways that trigger NETs formation in cancers. Additionally, this review will outline the current molecular mechanisms and regulatory networks of NETs during dormant cancer cells awakening, circulating tumor cells (CTCs) extravasation, and metastatic recurrence of cancer. This is followed by a perspective on the current and potential clinical potential of NETs as therapeutic targets in the treatment of both local and metastatic disease, including the improvement of the efficacy of existing therapies.

Post-COVID pulmonary injury in K18-hACE2 mice shows persistent neutrophils and neutrophil extracellular trap formation

The involvement of neutrophils in the lungs during the recovery phase of coronavirus disease 2019 (COVID-19) is not well defined mainly due to the limited accessibility of lung tissues from COVID-19 survivors. The lack of an appropriate small animal model has affected the development of effective therapeutic strategies. We here developed a long COVID mouse model to study changes in neutrophil phenotype and association with lung injury. Our data shows persistent neutrophil recruitment and neutrophil extracellular trap formation in the lungs for up to 30 days post-infection which correlates with lung fibrosis and inflammation.

Nanomedicines targeting activated immune cells and effector cells for rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovial inflammation and inflammatory cellular infiltration. Functional cells in the RA microenvironment (RAM) are composed of activated immune cells and effector cells. Activated immune cells, including macrophages, neutrophils, and T cells, can induce RA. Effector cells, including synoviocytes, osteoclasts, and chondrocytes, receiving inflammatory stimuli, exacerbate RA. These functional cells, often associated with the upregulation of surface-specific receptor proteins and significant homing effects, can secrete pro-inflammatory factors and interfere with each other, thereby jointly promoting the progression of RA. Recently, some nanomedicines have alleviated RA by targeting and modulating functional cells with ligand modifications, while other nanoparticles whose surfaces are camouflaged by membranes or extracellular vesicles (EVs) of these functional cells target and attack the lesion site for RA treatment. When ligand-modified nanomaterials target specific functional cells to treat RA, the functional cells are subjected to attack, much like the intended targets. When functional cell membranes or EVs are modified onto nanomaterials to deliver drugs for RA treatment, functional cells become the attackers, similar to arrows. This study summarized how diversified functional cells serve as targets or arrows by engineered nanoparticles to treat RA. Moreover, the key challenges in preparing nanomaterials and their stability, long-term efficacy, safety, and future clinical patient compliance have been discussed here.

Neutrophil Extracellular Traps: A Crucial Factor in Post-Surgical Abdominal Adhesion Formation

Post-surgical abdominal adhesions, although poorly understood, are highly prevalent. The molecular processes underlying their formation remain elusive. This review aims to assess the relationship between neutrophil extracellular traps (NETs) and the generation of postoperative peritoneal adhesions and to discuss methods for mitigating peritoneal adhesions. A keyword or medical subject heading (MeSH) search for all original articles and reviews was performed in PubMed and Google Scholar. It included studies assessing peritoneal adhesion reformation after abdominal surgery from 2003 to 2023. After assessing for eligibility, the selected articles were evaluated using the Critical Appraisal Skills Programme checklist for qualitative research. The search yielded 127 full-text articles for assessment of eligibility, of which 7 studies met our criteria and were subjected to a detailed quality review using the Critical Appraisal Skills Programme (CASP) checklist. The selected studies offer a comprehensive analysis of adhesion pathogenesis with a special focus on the role of neutrophil extracellular traps (NETs) in the development of peritoneal adhesions. Current interventional strategies are examined, including the use of mechanical barriers, advances in regenerative medicine, and targeted molecular therapies. In particular, this review emphasizes the potential of NET-targeted interventions as promising strategies to mitigate postoperative adhesion development. Evidence suggests that in addition to their role in innate defense against infections and autoimmune diseases, NETs also play a crucial role in the formation of peritoneal adhesions after surgery. Therefore, therapeutic strategies that target NETs are emerging as significant considerations for researchers. Continued research is vital to fully elucidate the relationship between NETs and post-surgical adhesion formation to develop effective treatments.

A local drug delivery system prolongs graft survival by dampening T cell infiltration and neutrophil extracellular trap formation in vascularized composite allografts

Introduction

The standard treatment for preventing rejection in vascularized composite allotransplantation (VCA) currently relies on systemic immunosuppression, which exposes the host to well-known side effects. Locally administered immunosuppression strategies have shown promising results to bypass this hurdle. Nevertheless, their progress has been slow, partially attributed to a limited understanding of the essential mechanisms underlying graft rejection. Recent discoveries highlight the crucial involvement of innate immune components, such as neutrophil extracellular traps (NETs), in organ transplantation. Here we aimed to prolong graft survival through a tacrolimus-based drug delivery system and to understand the role of NETs in VCA graft rejection.

Methods

To prevent off-target toxicity and promote graft survival, we tested a locally administered tacrolimus-loaded on-demand drug delivery system (TGMS-TAC) in a multiple MHC-mismatched porcine VCA model. Off-target toxicity was assessed in tissue and blood. Graft rejection was evaluated macroscopically while the complement system, T cells, neutrophils and NETs were analyzed in graft tissues by immunofluorescence and/or western blot. Plasmatic levels of inflammatory cytokines were measured using a Luminex magnetic-bead porcine panel, and NETs were measured in plasma and tissue using DNA-MPO ELISA. Lastly, to evaluate the effect of tacrolimus on NET formation, NETs were induced in-vitro in porcine and human peripheral neutrophils following incubation with tacrolimus.

Results

Repeated intra-graft administrations of TGMS-TAC minimized systemic toxicity and prolonged graft survival. Nevertheless, signs of rejection were observed at endpoint. Systemically, there were no increases in cytokine levels, complement anaphylatoxins, T-cell subpopulations, or neutrophils during rejection. Yet, tissue analysis showed local infiltration of T cells and neutrophils, together with neutrophil extracellular traps (NETs) in rejected grafts. Interestingly, intra-graft administration of tacrolimus contributed to a reduction in both T-cellular infiltration and NETs. In fact, in-vitro NETosis assessment showed a 62-84% reduction in NETs after stimulated neutrophils were treated with tacrolimus.

Conclusion

Our data indicate that the proposed local delivery of immunosuppression avoids off-target toxicity while prolonging graft survival in a multiple MHC-mismatch VCA model. Furthermore, NETs are found to play a role in graft rejection and could therefore be a potential innovative therapeutic target.

Neutrophil extracellular traps as a unique target in the treatment of inflammatory pain

Pain is a widespread motivation for seeking healthcare and stands as a substantial global public health concern. Despite comprehensive investigations into the mechanisms of pain sensitization induced by inflammation, efficacious treatments options remain scarce. Neutrophil extracellular traps (NETs) have been associated with the progression and tissue damage of diverse inflammatory diseases. This study aims to explore the impact of NETs on the progression of inflammatory pain and explore potential therapeutic approaches. Initially, we observed neutrophil infiltration and the formation of NETs in the left hind paw of mice with inflammatory pain induced by complete Freund's adjuvant (CFA). Furthermore, we employed the peptidyl arginine deiminase 4 (PAD4) inhibitor Cl-amidine (diluted at 50 mg/kg in saline, administered via tail vein injection once daily for three days) to impede NETs formation and administered DNase1 (diluted at 10 mg/kg in saline, once daily for three days) to break down NETs. We investigated the pathological importance of peripheral NETs formation in inflammatory pain and its influence on the activation of spinal dorsal horn microglia. The findings indicate that neutrophils infiltrating locally generate NETs, leading to an increased release of inflammatory mediators that worsen peripheral inflammatory reactions. Consequently, this results in the transmission of more harmful peripheral stimuli to the spinal cord, triggering microglial activation and NF-κB phosphorylation, thereby escalating neuroinflammation and fostering pain sensitization. Suppression of peripheral NETs can mitigate peripheral inflammation in mice with inflammatory pain, reverse mechanical and thermal hypersensitivity by suppressing microglial activation in the spinal cord, ultimately diminishing inflammatory pain. In conclusion, these discoveries propose that obstructing or intervening with NETs introduces a novel therapeutic avenue for addressing inflammatory pain.

Myocardial reperfusion injury exacerbation due to ALDH2 deficiency is mediated by neutrophil extracellular traps and prevented by leukotriene C4 inhibition

BACKGROUND AND AIMS

The Glu504Lys polymorphism in the aldehyde dehydrogenase 2 (ALDH2) gene is closely associated with myocardial ischaemia/reperfusion injury (I/RI). The effects of ALDH2 on neutrophil extracellular trap (NET) formation (i.e. NETosis) during I/RI remain unknown. This study aimed to investigate the role of ALDH2 in NETosis in the pathogenesis of myocardial I/RI.

METHODS

The mouse model of myocardial I/RI was constructed on wild-type, ALDH2 knockout, peptidylarginine deiminase 4 (Pad4) knockout, and ALDH2/PAD4 double knockout mice. Overall, 308 ST-elevation myocardial infarction patients after primary percutaneous coronary intervention were enrolled in the study.

RESULTS

Enhanced NETosis was observed in human neutrophils carrying the ALDH2 genetic mutation and ischaemic myocardium of ALDH2 knockout mice compared with controls. PAD4 knockout or treatment with NETosis-targeting drugs (GSK484, DNase1) substantially attenuated the extent of myocardial damage, particularly in ALDH2 knockout. Mechanistically, ALDH2 deficiency increased damage-associated molecular pattern release and susceptibility to NET-induced damage during myocardial I/RI. ALDH2 deficiency induced NOX2-dependent NETosis via upregulating the endoplasmic reticulum stress/microsomal glutathione S-transferase 2/leukotriene C4 (LTC4) pathway. The Food and Drug Administration-approved LTC4 receptor antagonist pranlukast ameliorated I/RI by inhibiting NETosis in both wild-type and ALDH2 knockout mice. Serum myeloperoxidase-DNA complex and LTC4 levels exhibited the predictive effect on adverse left ventricular remodelling at 6 months after primary percutaneous coronary intervention in ST-elevation myocardial infarction patients.

CONCLUSIONS

ALDH2 deficiency exacerbates myocardial I/RI by promoting NETosis via the endoplasmic reticulum stress/microsomal glutathione S-transferase 2/LTC4/NOX2 pathway. This study hints at the role of NETosis in the pathogenesis of myocardial I/RI, and pranlukast might be a potential therapeutic option for attenuating I/RI, particularly in individuals with the ALDH2 mutation.

A Neutrophil Hijacking Nanoplatform Reprograming NETosis for Targeted Microglia Polarizing Mediated Ischemic Stroke Treatment

Precise and efficient regulation of microglia is vital for ischemic stroke therapy and prognosis. The infiltration of neutrophils into the brain provides opportunities for regulatory drugs across the blood-brain barrier, while hindered by neutrophil extracellular traps (NETs) and targeted delivery of intracerebral drugs to microglia. This study reports an efficient neutrophil hijacking nanoplatform (referred to as APTS) for targeted A151 (a telomerase repeat sequence) delivery to microglia without the generation of NETs. In the middle cerebral artery occlusion (MCAO) mouse model, the delivery efficiency to ischemic stroke tissues increases by fourfold. APTS dramatically reduces the formation of NETs by 2.2-fold via reprogramming NETosis to apoptosis in neutrophils via a reactive oxygen species scavenging-mediated citrullinated histone 3 inhibition pathway. Noteworthy, A151 within neutrophils is repackaged into apoptotic bodies following the death pattern reprogramming, which, when engulfed by microglia, polarizes microglia to an anti-inflammatory M2 phenotype. After four times treatment, the cerebral infarction area in the APTS group decreases by 5.1-fold. Thus, APTS provides a feasible, efficient, and practical drug delivery approach for reshaping the immune microenvironment and treating brain disorders in the central nervous system.

Neutrophils and neutrophil extracellular traps in oral health and disease

Neutrophils perform essential functions in antimicrobial defense and tissue maintenance at mucosal barriers. However, a dysregulated neutrophil response and, in particular, the excessive release of neutrophil extracellular traps (NETs) are implicated in the pathology of various diseases. In this review, we provide an overview of the basic concepts related to neutrophil functions, including NET formation, and discuss the mechanisms associated with NET activation and function in the context of the prevalent oral disease periodontitis.

Cocaine-use disorder and childhood maltreatment are associated with the activation of neutrophils and increased inflammation

BACKGROUND

Cocaine-use disorder (CUD) has been associated with early life adversity and activated cellular immune responses. Women are most vulnerable to complications from chronic substance disorders, generally presenting an intense feeling of abstinence and consuming significant drug amounts. Here, we investigated neutrophil functional activities in CUD, including the formation of neutrophil extracellular traps (NETs) and related intracellular signalling. We also investigated the role of early life stress in inflammatory profiles.

METHODS

Blood samples, clinical data, and history of childhood abuse or neglect were collected at the onset of detoxification treatment of 41 female individuals with CUD and 31 healthy controls (HCs). Plasma cytokines, neutrophil phagocytosis, NETs, intracellular reactive oxygen species (ROS) generation, and phosphorylated protein kinase B (Akt) and mitogen-activated protein kinases (MAPK)s were assessed by flow cytometry.

RESULTS

CUD subjects had higher scores of childhood trauma than controls. Increased plasma cytokines (TNF-α, IL-1β, IL-6, IL-8, IL-12, and IL-10), neutrophil phagocytosis, and production of NETs were reported in CUD subjects as compared to HC. Neutrophils of CUD subjects also produced high levels of intracellular ROS and had more activated Akt and MAPKs (p38/ERK), which are essential signalling pathways involved in cell survival and NETs production. Childhood trauma scores were significantly associated with neutrophil activation and peripheral inflammation.

CONCLUSION

Our study reinforces that smoked cocaine and early life stress activate neutrophils in an inflammatory environment.

Neutrophil-inflicted vasculature damage suppresses immune-mediated optic nerve regeneration

In adult mammals, injured retinal ganglion cells (RGCs) fail to spontaneously regrow severed axons, resulting in permanent visual deficits. Robust axon growth, however, is observed after intra-ocular injection of particulate β-glucan isolated from yeast. Blood-borne myeloid cells rapidly respond to β-glucan, releasing numerous pro-regenerative factors. Unfortunately, the pro-regenerative effects are undermined by retinal damage inflicted by an overactive immune system. Here, we demonstrate that protection of the inflamed vasculature promotes immune-mediated RGC regeneration. In the absence of microglia, leakiness of the blood-retina barrier increases, pro-inflammatory neutrophils are elevated, and RGC regeneration is reduced. Functional ablation of the complement receptor 3 (CD11b/integrin-αM), but not the complement components C1q-/- or C3-/-, reduces ocular inflammation, protects the blood-retina barrier, and enhances RGC regeneration. Selective targeting of neutrophils with anti-Ly6G does not increase axogenic neutrophils but protects the blood-retina barrier and enhances RGC regeneration. Together, these findings reveal that protection of the inflamed vasculature promotes neuronal regeneration.

Neutrophil hitchhiking nanoparticles enhance bacteria-mediated cancer therapy via NETosis reprogramming

Bacteria have shown great potential in anti-tumor treatment, and an attenuated strain of Salmonella named VNP20009 has been shown to be safe in clinical trials. However, colonized bacteria recruit neutrophils into the tumor, which release NETs to capture and eliminate bacteria, compromising bacterial-based tumor treatment. In this study, we report a neutrophil hitchhiking nanoparticles (SPPS) that block the formation of NET to enhance bacteria-mediated tumor therapy. In the 4 T1 tumor-bearing mouse model, following 24 h of bacterial therapy, there was an approximately 3.0-fold increase in the number of neutrophils in the bloodstream, while the amount of SPPS homing to tumor tissue through neutrophil hitchhiking increased approximately 2.0-fold. It is worth noting that the NETs in tumors significantly decreased by approximately 2.0-fold through an intracellular ROS scavenging-mediated NETosis reprogramming, thereby increasing bacterial vitality by 1.9-fold in tumors. More importantly, the gene drug (siBcl-2) loaded in SPPS can be re-encapsulated in apoptotic bodies by reprogramming neutrophils from NETosis to apoptosis, and enable the redelivery of drugs to tumor cells, further boosting the antitumor efficacy with a synergistic effect, resulting in about 98% tumor inhibition rate and 90% survival rate.

Pathogenesis-Guided Rational Engineering of Nanotherapies for the Targeted Treatment of Abdominal Aortic Aneurysm by Inhibiting Neutrophilic Inflammation

Abdominal aortic aneurysm (AAA) remains a fatal disease in the elderly. Currently, no drugs can be clinically used for AAA therapy. Considering the pivotal role of neutrophils in the pathogenesis of AAA, herein we propose the targeted therapy of AAA by site-specifically regulating neutrophilic inflammation. Based on a luminol-conjugated α-cyclodextrin material (LaCD), intrinsically anti-inflammatory nanoparticles (NPs) were engineered by simple nanoprecipitation, which were examined as a nanotherapy (defined as LaCD NP). After efficient accumulation in the aneurysmal aorta and localization in pathologically relevant inflammatory cells in rats with CaCl2-induced AAA, LaCD NP significantly alleviated AAA progression, as implicated by the decreased aortic expansion, suppressed elastin degradation, inhibited calcification, and improved structural integrity of the abdominal aorta. By functionalizing LaCD NP with alendronate, a calcification-targeting moiety, the in vivo aneurysmal targeting capability of LaCD NP was considerably enhanced, thereby affording significantly potentiated therapeutic outcomes in AAA rats. Mechanistically, LaCD NP can effectively inhibit neutrophil-mediated inflammatory responses in the aneurysmal aorta. Particularly, LaCD NP potently attenuated the formation of neutrophil extracellular traps (NETs), thereby suppressing NETs-mediated pro-inflammatory events and NETosis-associated negative effects responsible for AAA progression. Consequently, we demonstrated the effectiveness and underlying mechanisms of anti-NETosis nanotherapies for the targeted treatment of AAA. Our findings provide promising insights into discovering precision therapies for AAA and other inflammatory vascular diseases.

Identification of potential biological processes and key genes in diabetes-related stroke through weighted gene co-expression network analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an established risk factor for acute ischemic stroke (AIS). Although there are reports on the correlation of diabetes and stroke, data on its pathogenesis is limited. This study aimed to explore the underlying biological mechanisms and promising intervention targets of diabetes-related stroke.

METHODS

Diabetes-related datasets (GSE38642 and GSE44035) and stroke-related datasets (GSE16561 and GSE22255) were obtained from the Gene Expression omnibus (GEO) database. The key modules for stroke and diabetes were identified by weight gene co-expression network analysis (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes Genomes (KEGG) analyses were employed in the key module. Genes in stroke- and diabetes-related key modules were intersected to obtain common genes for T2DM-related stroke. In order to discover the key genes in T2DM-related stroke, the Cytoscape and protein-protein interaction (PPI) network were constructed. The key genes were functionally annotated in the Reactome database.

RESULTS

By intersecting the diabetes- and stroke-related crucial modules, 24 common genes for T2DM-related stroke were identified. Metascape showed that neutrophil extracellular trap formation was primarily enriched. The hub gene was granulin precursor (GRN), which had the highest connectivity among the common genes. In addition, functional enrichment analysis indicated that GRN was involved in neutrophil degranulation, thus regulating neutrophil extracellular trap formation.

CONCLUSIONS

This study firstly revealed that neutrophil extracellular trap formation may represent the common biological processes of diabetes and stroke, and GRN may be potential intervention targets for T2DM-related stroke.

Dietary modulation of gut microbiota affects susceptibility to drug-induced liver injury

The rising incidence of drug-induced liver injury (DILI) parallels contemporary dietary shifts that have transformed the composition of human gut microbiota. The relationship between these phenomena remains unknown. Here, it is unveiled that a high fiber diet (HFiD) provides substantial protection against DILI, whereas a western style diet (WSD) significantly exacerbates DILI. Gut microbiota transplantation further confirms these differing outcomes are mediated by diet-induced variations in gut microbiota. Mechanistically, Lactobacillus acidophilus, enriched by HFiD, alleviates DILI through its metabolite indole-3-lactic acid (ILA), which activates the AhR/Nrf2 signaling pathway, thus enhancing hepatocellular antioxidant defenses and detoxification capacity. In the clinical intervention of subjects with prediabetes (N = 330), dietary fiber intervention enriches intestinal L. acidophilus, elevates serum ILA levels, and improves liver function. Conversely, WSD induces disturbance in bile acid metabolism and dysbiosis in gut microbiota, which impairs the intestinal barrier and facilitates the translocation of lipopolysaccharides (LPS) to the liver, thus triggering inflammatory responses and exacerbating DILI. These results demonstrate that dietary patterns significantly influence the onset of DILI by modulating gut microbiota. This novel insight expands the understanding of DILI risk factors and highlights the potential of dietary modifications as a preventive strategy against DILI.

NETosis: Sculpting tumor metastasis and immunotherapy

The process of neutrophil extracellular traps (NETs) formation, called NETosis, is a peculiar death modality of neutrophils, which was first observed as an immune response against bacterial infection. However, recent work has revealed the unique biology of NETosis in facilitating tumor metastatic process. Neutrophil extracellular traps released by the tumor microenvironment (TME) shield tumor cells from cytotoxic immunity, leading to impaired tumor clearance. Besides, tumor cells tapped by NETs enable to travel through vessels and subsequently seed distant organs. Targeted ablation of NETosis has been proven to be beneficial in potentiating the efficacy of cancer immunotherapy in the metastatic settings. This review outlines the impact of NETosis at almost all stages of tumor metastasis. Furthermore, understanding the multifaceted interplay between NETosis and the TME components is crucial for supporting the rational development of highly effective combination immunotherapeutic strategies with anti-NETosis for patients with metastatic disease.

A variety of death modes of neutrophils and their role in the etiology of autoimmune diseases

Neutrophils are important in the context of innate immunity and actively contribute to the progression of diverse autoimmune disorders. Distinct death mechanisms of neutrophils may exhibit specific and pivotal roles in autoimmune diseases and disease pathogenesis through the orchestration of immune homeostasis, the facilitation of autoantibody production, the induction of tissue and organ damage, and the incitement of pathological alterations. In recent years, more studies have provided in-depth examination of various neutrophil death modes, revealing nuances that challenge conventional understanding and underscoring their potential clinical utility in diagnosis and treatment. This review explores the multifaceted processes and characteristics of neutrophil death, with a focus on tailored investigations within various autoimmune diseases. It also highlights the potential interplay between neutrophil death and the landscape of autoimmune disorders. The review encapsulates the pertinent pathways implicated in various neutrophil death mechanisms across diverse autoimmune diseases while also charts possible avenues for future research.

To Gain Insights into the Pathophysiological Mechanisms of the Thrombo-Inflammatory Process in the Atherosclerotic Plaque

Thromboinflammation, the interplay between thrombosis and inflammation, is a significant pathway that drives cardiovascular and autoimmune diseases, as well as COVID-19. SARS-CoV-2 causes inflammation and blood clotting issues. Innate immune cells have emerged as key modulators of this process. Neutrophils, the most predominant white blood cells in humans, are strategically positioned to promote thromboinflammation. By releasing decondensed chromatin structures called neutrophil extracellular traps (NETs), neutrophils can initiate an organised cell death pathway. These structures are adorned with histones, cytoplasmic and granular proteins, and have cytotoxic, immunogenic, and prothrombotic effects that can hasten disease progression. Protein arginine deiminase 4 (PAD4) catalyses the citrullination of histones and is involved in the release of extracellular DNA (NETosis). The neutrophil inflammasome is also required for this process. Understanding the link between the immunological function of neutrophils and the procoagulant and proinflammatory activities of monocytes and platelets is important in understanding thromboinflammation. This text discusses how vascular blockages occur in thromboinflammation due to the interaction between neutrophil extracellular traps and ultra-large VWF (von Willebrand Factor). The activity of PAD4 is important for understanding the processes that drive thromboinflammation by linking the immunological function of neutrophils with the procoagulant and proinflammatory activities of monocytes and platelets. This article reviews how vaso-occlusive events in thrombo-inflammation occur through the interaction of neutrophil extracellular traps with von Willebrand factor. It highlights the relevance of PAD4 in neutrophil inflammasome assembly and neutrophil extracellular traps in thrombo-inflammatory diseases such as atherosclerosis and cardiovascular disease. Interaction between platelets, VWF, NETs and inflammasomes is critical for the progression of thromboinflammation in several diseases and was recently shown to be active in COVID-19.

Bacterial Brain Abscesses Expand Despite Effective Antibiotic Treatment: A Process Powered by Osmosis Due to Neutrophil Cell Death

BACKGROUND AND OBJECTIVES

A bacterial brain abscess is an emergency and should be drained of pus within 24 hours of diagnosis, as recently recommended. In this cross-sectional study, we investigated whether delaying pus drainage entails brain abscess expansion and what the underlying mechanism might be.

METHODS

Repeated brain MRI of 47 patients who did not undergo immediate pus drainage, pus osmolarity measurements, immunocytochemistry, proteomics, and 18F-fluorodeoxyglucose positron emission tomography.

RESULTS

Time from first to last MRI before neurosurgery was 1 to 14 days. Abscesses expanded in all but 2 patients: The median average increase was 23% per day (range 0%-176%). Abscesses expanded during antibiotic therapy and even if the pus did not contain viable bacteria. In a separate patient cohort, we found that brain abscess pus tended to be hyperosmolar (median value 360 mOsm; range 266-497; n = 14; normal cerebrospinal fluid osmolarity is ∼290 mOsm). Hyperosmolarity would draw water into the abscess cavity, causing abscess expansion in a ballooning manner through increased pressure in the abscess cavity. A mechanism likely underlying pus hyperosmolarity was the recruitment of neutrophils to the abscess cavity with ensuing neutrophil cell death and decomposition of neutrophil proteins and other macromolecules to osmolytes: Pus analysis showed the presence of neutrophil proteins (protein-arginine deiminases, citrullinated histone, myeloperoxidase, elastase, cathelicidin). Previous studies have shown very high levels of osmolytes (ammonia, amino acids) in brain abscess pus. 18F-fluorodeoxyglucose positron emission tomography showed focal neocortical hypometabolism 1 to 8 years after brain abscess, indicating long-lasting damage to brain tissue.

CONCLUSION

Brain abscesses expand despite effective antibiotic treatment. Furthermore, brain abscesses cause lasting damage to surrounding brain tissue. These findings support drainage of brain abscesses within 24 hours of diagnosis.