The review, led by Leyu Ai, Huirong Wu, and colleagues, synthesizes a rapidly expanding body of evidence linking lactylation—a posttranslational modification first reported in 2019 by Yingming Zhao’s team—to regulated cell death (RCD), the family of programmed cell death pathways that includes apoptosis, ferroptosis, pyroptosis, PANoptosis, and NETosis. The central thesis is striking: when sepsis forces cells into a glycolytic metabolic state, the resulting lactate surge doesn’t just accumulate harmlessly. It is converted into lactyl-coenzyme A, which competes with acetyl-CoA for the same lysine residues on histones and nonhistone proteins, shifting the entire cellular acylation landscape toward lactylation and away from acetylation.

The mechanistic logic is elegant. Under healthy conditions, oxidative phosphorylation dominates glucose metabolism, generating abundant acetyl-CoA that drives lysine acetylation—the prevailing protein modification. Enzymes like the bifunctional acyltransferase AARS1 show a marked kinetic preference for acetyl-CoA: its Michaelis constant for acetyl-CoA is roughly 80 micromolar, compared with approximately 36 millimolar for lactyl-CoA, meaning the enzyme’s affinity for the acetyl substrate is orders of magnitude higher. But sepsis flips this balance. Hypoxia-inducible factor-1α upregulates lactate dehydrogenase A, while phosphorylation of the pyruvate dehydrogenase complex by PDK1/4 suppresses acetyl-CoA production. The resulting lactyl-CoA flood overwhelms the enzymatic threshold, allowing lactylation to seize dominance at shared modification sites.

Clinical data support this model. In a prospective cohort of 86 critically ill patients, serum lactate levels correlated positively with H3K18la—a histone lactylation mark at lysine 18 of histone H3—while H3K18ac levels fell. The H3K18la/ac ratio correlated with disease severity scores (APACHE II and SOFA), ICU length of stay, and duration of mechanical ventilation, suggesting the modification ratio itself may serve as a biomarker. Earlier work by Chu and colleagues found H3K18la highest in septic shock patients, correlating with inflammatory cytokines and macrophage polarization markers.

But the review’s most provocative contribution lies in mapping how these lactylation marks regulate cell death across organs. In sepsis-associated acute kidney injury—which affects up to 66 percent of septic patients—elevated H3K18la in renal tubular epithelial cells activates the RhoA/ROCK pathway and the Ezrin-MYD88-IRAK1-NF-κB inflammatory cascade, driving apoptosis. Nonhistone lactylation compounds the damage: excessive acetylation and inactivation of PDHA1 leads to lactate overproduction, which then induces lactylation of the mitochondrial fission protein Fis1 at lysine 20, triggering excessive mitochondrial fragmentation and tubular cell death.

In the lung, the picture is equally complex. Histone lactylation at H3K18 promotes alveolar epithelial apoptosis through at least two routes: it upregulates caspase-8, amplifying TNF-α-mediated pro-apoptotic signaling, and it drives EGR1 transcription and nuclear import, degrading the endothelial glycocalyx barrier. Meanwhile, lactylation regulates ferroptosis—iron-dependent lipid peroxidation-driven cell death—through multiple histone marks. H3K14la-mediated transcription upregulates the transferrin receptor TFRC and downregulates SLC40A1, creating iron overload that catalyzes reactive oxygen species via the Fenton reaction. H3K18la enriches at the promoters of ACSL4 and LC3, increasing polyunsaturated fatty acid content and promoting ferritinophagy. A protective feedback loop also exists: elevated H3K14la upregulates PARK7, which restores FADS1/2 enzyme activity and activates the NRF2/KEAP1 antioxidant pathway, suppressing ferroptosis.

Pyroptosis—inflammatory cell death executed by gasdermin pore formation—is another major target. Lactate entering macrophages via monocarboxylate transporter 1 is converted by AARS2 into lactyl-CoA, which mediates site-specific lactylation of NLRP3 at lysines 24 and 565. This modification promotes recruitment of the adaptor protein ASC and assembly of the NLRP3 inflammasome, activating caspase-1, cleaving GSDMD, and releasing mature IL-1β. In the brain, H3K18la upregulates YTHDF3, which stabilizes NLRP3 via the deubiquitinase USP9X, triggering microglial pyroptosis and neuroinflammation. In the kidney, H3K18la activates SPHK1, which phosphorylates and degrades SIRT1—disrupting both a delactylase feedback loop and mitochondrial homeostasis, creating a vicious cycle that amplifies pyroptotic injury.

Perhaps most intriguingly, the review documents bidirectional regulation. In macrophages, MCT1-dependent lactylation of ZBP1 disrupts its interaction with RIPK1/TRIF, promoting ZBP1 degradation and blocking ZBP1-mediated PANoptosis—thereby alleviating lung injury. Conversely, lactylation of CIRP promotes its nuclear-to-cytoplasmic translocation and exosomal release, which endothelial cells internalize via TLR4, stabilizing ZBP1 and enhancing PANoptosis in pulmonary epithelial cells. The same modification, acting on different substrates in different cell types, can either protect or destroy.

The authors also highlight autophagy as a newly identified lactylation target with bidirectional effects. During the hyperinflammatory phase, neutrophil-derived lactate drives H3K18la-mediated upregulation of ATG7, initiating nondegradative secretory autophagy that releases IL-1β and damages pulmonary endothelium. During the immunosuppressive phase, impaired glycolytic reprogramming reduces lactate production, lowering H3K18la and attenuating transcription of ATG5 and ATG16L1—crippling macrophage autophagic flux and bactericidal capacity, thereby promoting immune paralysis.

What emerges is a systems-level view: sepsis is not simply a cytokine storm or a circulatory collapse, but a global epigenetic reprogramming event in which metabolic flux dictates protein modification state, which in turn dictates cell fate. The review proposes that glucose metabolic flux distribution serves as a critical regulatory node—determining not only overall levels of acetylation and lactylation but also their spatiotemporal specificity. Multiorgan metabolomic studies showing enhanced metabolic coupling among abdominal organs, with decoupling of heart and skeletal muscle, suggest that systemic metabolic fluctuations may reshape lactylation profiles across organs simultaneously, mediating synchronous multiorgan injury before clinical dysfunction is detectable.

The clinical implications are substantial but preliminary. Existing lactylation research remains largely confined to single-center observational biomarker studies with small cohorts. No interventional clinical trials targeting the lactylation pathway have been reported. The enzyme kinetic data supporting the acylation competition model derive from in vitro purified systems; subcellular compartmentalization and cofactor microenvironments may reshape actual catalytic preferences in vivo. The lactate concentration threshold that drives modification preference shifts in bifunctional acyltransferases has not been systematically defined.

Artificial intelligence may accelerate the field. Deep learning tools like DeepKla can predict lysine lactylation sites with 93.22 percent accuracy. AI-driven multiomics frameworks have stratified patients into LDHA-high and LDHA-low subtypes with distinct prognoses, achieving sensitivity of 0.922 and precision of 0.955 in predicting lactylation-driven therapeutic responses. In pyroptosis research, a Transformer model trained on 40,000 protein interface data points generated the SK56 peptide, which specifically blocks the GSDMD-NT pore, delaying pyroptosis and alleviating inflammation. The review proposes an integrated multimodal model combining early sepsis warning, lactylation site identification, and RCD pathway intervention—a full-chain system spanning early detection through precision targeting.

Ultimately, the lactylation–RCD axis offers a fundamentally new therapeutic logic for sepsis. Rather than nonspecifically lowering systemic lactate, future strategies may target cell-selective metabolic intervention: modulating lactate synthesis or lactyl-CoA generation in specific cell subtypes to restore intracellular lactylation to physiological homeostatic range, thereby blocking RCD-mediated parenchymal organ injury while preserving myeloid pathogen clearance and immune defense. The field remains in its infancy, but the convergence of epigenetics, cell death biology, and artificial intelligence suggests that the humble lactate molecule—long dismissed as a metabolic dead end—may hold the key to rewriting the outcome of one of humanity’s deadliest syndromes.

Subject of Research: Sepsis, lactylation, regulated cell death, epigenetics, metabolic reprogramming

Article Title: Recent advances in research on the association between lactylation and regulated cell death in sepsis

Article References: Ai, L., Wu, H., Huang, W., Zhang, Y., Ma, Y., Wu, D., Chen, J., Fang, X., Liu, C., Wang, P., Cheng, W., Fu, H., Yin, W., Shen, K., & Li, J. (2026). Recent advances in research on the association between lactylation and regulated cell death in sepsis. Journal of Advanced Research. https://doi.org/10.1016/j.jare.2026.10.026

Image Credits: AI Generated

DOI: 10.1016/j.jare.2026.10.026

Keywords: sepsis, lactylation, regulated cell death, apoptosis, ferroptosis, pyroptosis, PANoptosis, NETosis, epigenetics, metabolic reprogramming, H3K18la, lactate

NETosis is a spectacular and violent form of cell death. When a neutrophil is activated, it decondenses its own nucleus, mixes its DNA with cytoplasmic and granule proteins, and casts the whole tangle outward as a web-like structure that can snare and neutralize pathogens. The process is a cornerstone of innate immunity, but it has a dark side. In rheumatoid arthritis, proteins externalized during NETosis can become citrullinated, sparking the generation of anti-citrullinated protein antibodies, or ACPA, the hallmark autoantibodies of the disease. NETs correlate with disease activity in RA patients, and in systemic lupus erythematosus, a relative inability to degrade NETs has been linked to a higher incidence of lupus nephritis, one of the most serious complications of the disease.

What makes the new findings especially provocative is the demographic backdrop. Autoimmune diseases in which NETs are implicated strike women far more often than men, and the skew is most extreme during the premenopausal years. Rheumatoid arthritis shows a female-to-male ratio of roughly 5:1 in premenopausal women, and lupus reaches an astonishing 10:1. Neutrophils from premenopausal women display a more mature and responsive phenotype than male neutrophils, with a correspondingly greater propensity for NET formation, and estrogen itself can drive this pro-NETotic behavior. That observation placed oral contraceptives squarely in the crosshairs of the Colorado team, led by Daniele Marcy and M. Kristen Demoruelle, because the pill commonly induces anovulation and thereby lowers total systemic estrogen exposure.

The researchers drew on the Studies of the Etiology of Rheumatoid Arthritis, or SERA, an observational project running since 2005 that follows first-degree relatives of people with established RA alongside healthy community controls. From stored plasma samples, the team assembled three groups of premenopausal women: a derivation cohort of 77 healthy women, a validation cohort of 87 healthy women, and a cohort of 104 women at elevated risk for RA because a first-degree relative had the disease. All participants completed detailed questionnaires on contraceptive, pregnancy, and smoking histories, and blood was drawn in EDTA tubes, processed within 30 minutes, and stored at minus 80 degrees Celsius until batch testing.

To gauge NETosis, the team measured plasma calprotectin, a heterodimer of the alarmin proteins S100A8 and S100A9 that are highly abundant in the neutrophil cytoplasm and released during NET formation. Calprotectin is a well-established marker of neutrophil activation and correlates with inflammation in NET-associated diseases, and because it can be quantified with a widely available commercial ELISA kit, the assay offers low inter-assay variability and a plausible path into routine clinical care. Importantly, the researchers excluded anti-CCP-positive individuals, since ACPA can independently induce NETosis and would muddy the interpretation. Laboratory technicians were blinded to each sample’s contraceptive status.

The results were strikingly consistent. Among healthy women in the derivation cohort, current pill users had a mean calprotectin level of 0.99 micrograms per milliliter compared with 1.38 in never or prior users, a difference that reached statistical significance at p equals 0.016. The validation cohort reproduced the pattern, with 0.9 versus 1.4 micrograms per milliliter and a p value of 0.001. In the at-risk relatives, current users again measured lower, at 1.19 versus 1.74 micrograms per milliliter, p equals 0.017. In multivariable linear regression models adjusting for age, ever smoking, and ever pregnancy—variables previously linked to NET levels—the association held, with borderline significance in the derivation cohort and a highly significant result in the validation cohort, where pill users averaged 0.56 micrograms per milliliter less calprotectin. Among the at-risk women, the adjusted difference was 0.73 micrograms per milliliter.

Notably, the effect did not appear to accumulate over time. There was no correlation between calprotectin levels and the duration of pill use, nor between calprotectin and the years elapsed since discontinuation among prior users. The authors argue this fits a model in which OCP-induced anovulation suppresses the high peri-ovulatory estradiol peaks that push neutrophils toward a NET-prone phenotype, an effect that begins shortly after initiation and reverses quickly upon stopping. When the team could confirm formulations through medical chart review, all 36 women documented were taking low-dose estradiol preparations of 0.035 milligrams or less, and estradiol dosage itself showed no correlation with calprotectin levels.

The numbers also sit sensibly within known biology. Mean calprotectin among healthy never or prior pill users, around 1.4 micrograms per milliliter, falls toward the upper end of the typical published range of 0.1 to 1.5, while the at-risk cohort’s never users averaged a modestly elevated 1.74. By contrast, patients with active rheumatoid arthritis commonly show calprotectin levels in the range of 10 to 50 micrograms per milliliter, underscoring that the study captured differences in a healthy or very early at-risk state rather than florid inflammation. The choice of EDTA-preserved plasma rather than serum also matters, since clotting during serum generation can activate neutrophils ex vivo and artificially inflate measured calprotectin.

The authors are careful about what the study can and cannot claim. As a cross-sectional analysis, it demonstrates association, not causation, and calprotectin release is not exclusive to NETosis—neutrophil necrosis and degranulation can also contribute. The team did not directly measure estradiol levels or confirm ovulatory status with luteinizing hormone surges, and no participants developed clinical RA during follow-up, precluding direct assessment of whether reduced NETosis actually mediates the lower RA risk previously reported in pill users. Still, multiple epidemiologic studies, including the Swedish EIRA study, have linked oral contraceptive use to reduced RA risk and to lower positivity for rheumatoid factor, and the new data offer a candidate mechanism: dampening NET formation and the citrullinated antigens it generates during a critical window of immune priming.

Future work, the researchers say, should extend these observations to women with established RA and lupus, examine neutrophil function before and after pill initiation in vivo, and test whether other hormonal contraceptives differing in estrogen dose, formulation, and route of administration produce similar effects. The study was funded by the National Institutes of Health and the University of Colorado Anschutz Ludeman Family Center for Women’s Health Research, and it appears in Frontiers in Lupus. If confirmed longitudinally, the findings could reframe a daily pill taken by millions as an unexpected modulator of innate immunity—one that may quietly influence which women’s neutrophils never fire their traps at all.

Subject of Research: Immunology

Article Title: Oral contraceptive pill Use is associated with lower levels of plasma calprotectin in premenopausal women

Article References: Marcy, D., Maretz, C., Sturm, K., Lugo, C., Deane, K. D., Holers, V. M., Norris, J. M., Zell, J., & Demoruelle, M. K. (2026). Oral contraceptive pill Use is associated with lower levels of plasma calprotectin in premenopausal women. Frontiers in Lupus, 4, Article 1819508. https://doi.org/10.3389/flupu.2026.1819508

Image Credits: AI Generated

DOI: 10.3389/flupu.2026.1819508

Keywords: oral contraceptives, calprotectin, NETosis, neutrophil extracellular traps, rheumatoid arthritis, lupus, autoimmune disease, estrogen, premenopausal women, immunology, women's health, biomarkers

The review, led by researchers examining the mechanistic underpinnings of synaptic damage and regeneration, synthesizes findings from studies spanning 2010 to 2026. Its central thesis is provocative: while amyloid plaques and neurofibrillary tangles are the visible hallmarks of the disease, the cognitive symptoms patients experience correlate far more strongly with the loss of synaptic density than with plaque burden alone. Studies cited in the review show that some individuals accumulate substantial amyloid without showing clear cognitive impairment, yet the erosion of synaptic connections tracks closely with deficits in learning and memory. This reframing shifts the therapeutic spotlight from simply clearing plaques to preserving and rebuilding the brain’s communication infrastructure.

At the heart of synaptic vulnerability lies a metabolic crisis. Synapses are among the most energy-hungry structures in the body, demanding a constant and precisely regulated supply of ATP to maintain ion gradients, mobilize synaptic vesicles, and sustain the calcium signaling that underlies neurotransmission. Mitochondria—the cellular power plants—cluster near synaptic terminals to meet this demand, but in Alzheimer’s disease they falter. The review details how respiratory chain complexes I and IV become impaired, reducing ATP production while simultaneously increasing the generation of reactive oxygen species (ROS). This oxidative flood damages mitochondrial DNA, peroxidizes synaptic membrane lipids, and disrupts the fusion pore opening required for vesicle release, causing vesicles to pile up at presynaptic terminals. In mouse models of the disease, synaptic mitochondria accumulate amyloid-beta in an age-dependent manner, compounding the bioenergetic deficit.

The consequences cascade. Elevated ROS activates stress pathways including p38 MAPK and JNK, which degrade synaptic proteins and impair long-term potentiation (LTP)—the cellular mechanism by which memories are encoded. Oxidative stress also inhibits protein phosphatases PP1 and PP2A, promoting the hyperphosphorylation of tau protein by kinases GSK-3β and CDK5. Hyperphosphorylated tau detaches from microtubules, destabilizing the neuronal cytoskeleton and halting the axonal transport of synaptic vesicles and mitochondria to the terminals that desperately need them. The result is a feed-forward loop in which energy failure, oxidative damage, and cytoskeletal collapse reinforce one another, progressively starving the synapse into dysfunction.

But the cytoskeleton is more than a passive victim. The review emphasizes that actin filaments and microtubules are active participants in synaptic repair. Actin, comprising roughly 90 percent of the cytoskeletal mass in dendritic spines, drives the polymerization cycles that enlarge spine heads during LTP and anchor AMPA receptors at the postsynaptic density. Microtubules transiently invade dendritic spines during activity-dependent remodeling, delivering messenger RNAs, PSD95, and mitochondria needed for spine growth and maintenance. Motor proteins—myosin V and VI for short-range transport within spines, kinesin and dynein for long-range cargo movement along microtubules—orchestrate this logistics network. In Alzheimer’s disease, soluble tau oligomers hijack this system: they preferentially target presynaptic GABAergic terminals, interact with Fyn kinase to gain rapid internalization at synaptic sites, and degrade the local cytoskeleton. Cofilin, an actin-binding protein, becomes hyperactivated and forms cofilin-actin rods that physically obstruct intracellular trafficking. The review notes that drebrin, a critical F-actin stabilizer abundant at excitatory synapses, is dramatically depleted in the hippocampus of Alzheimer’s patients, correlating with cognitive impairment.

Adding another layer of complexity, the review examines the role of exosomes—tiny extracellular vesicles 30 to 200 nanometers in diameter that shuttle proteins, lipids, and regulatory RNAs between cells. Under healthy conditions, neuronal exosomes deliver neurotransmitter transporters to presynaptic active zones and transport AMPA and NMDA receptors to dendritic spines in an activity-dependent manner. They carry microRNAs such as miR-124 and miR-132 that regulate synaptic plasticity and maintain the integrity of the blood-brain barrier. But in Alzheimer’s disease, exosomes become double agents. Astrocyte-derived exosomes carry elevated levels of oligomeric amyloid-beta and tau, spreading pathology from cell to cell. Exosomal amyloid-beta(1-42) binds to NMDA receptor GluN2B subunits, triggering aberrant calcium influx and excitotoxicity, while simultaneously enhancing the internalization of AMPA receptors and disrupting calcium-dependent signaling through CaMKII and PKA. The net effect is a degradation of long-term potentiation and an acceleration of long-term depression, eroding the synaptic plasticity that memory depends upon. Yet exosomes are not uniformly destructive—some facilitate amyloid clearance by delivering the peptide to microglial lysosomes for degradation, highlighting their context-dependent dual role.

The review also spotlights an emerging and less-explored contributor: NETosis, the process by which neutrophils release decondensed DNA, histones, and cytotoxic enzymes to trap pathogens. While NETosis is a normal host-defense mechanism, excessive activation in Alzheimer’s disease releases histones that act as damage-associated molecular patterns, activating microglial TLR/NF-κB signaling and promoting complement-driven synaptic pruning. NET-derived enzymes such as myeloperoxidase and neutrophil elastase degrade the extracellular matrix surrounding synapses, while matrix metalloproteinases—normally regulated contributors to synaptic plasticity—become overactivated and destabilize synaptic architecture. Neutrophils have been observed migrating toward amyloid plaques in mouse models, binding through LFA-1 integrin and crossing a compromised blood-brain barrier. The review acknowledges that direct in vivo evidence linking NETosis specifically to synaptic terminal loss remains limited, but the mechanistic framework—histone-mediated microglial activation, protease-driven matrix degradation, and barrier disruption—presents a compelling case for NETosis as an amplifier of synaptic injury.

Against this backdrop of interconnected pathology, the review positions phytochemicals as uniquely suited therapeutic agents. Unlike single-target synthetic drugs, compounds such as curcumin, resveratrol, quercetin, epigallocatechin gallate (EGCG), ferulic acid, and ginkgolide B act simultaneously on multiple nodes of the synaptic damage network. Curcumin activates the Nrf-2/ARE pathway, releasing the transcription factor from its cytosolic anchor Keap1 to induce antioxidant defense genes. Resveratrol promotes mitochondrial biogenesis through SIRT1 activation. Quercetin modulates NETosis and suppresses NF-κB signaling. EGCG remodels toxic amyloid-beta fibrils into non-toxic aggregates. Ferulic acid restores energy status and promotes mitochondrial biogenesis in preclinical studies. These compounds also enhance BDNF-TrkB signaling, activating downstream ERK, Akt, and CREB cascades that drive dendritic spine formation and synaptic protein synthesis. The review notes that two FDA-approved Alzheimer’s drugs—galantamine, derived from the snowdrop plant, and rivastigmine, based on a compound from the Calabar bean—are themselves phytochemical derivatives, lending translational credibility to the approach.

Delivery remains the critical bottleneck. Many phytochemicals suffer from poor bioavailability and limited blood-brain barrier penetration, and the review highlights nanoparticle formulations and engineered exosomes as promising solutions. Engineered exosomes can cross the blood-brain barrier and deliver therapeutic cargo directly to compromised synapses, potentially protecting against microglial over-pruning and amyloid-induced toxicity with fewer systemic side effects. The review also points to biomarker-driven approaches using exosomal profiling at the mild cognitive impairment stage as a means of assessing synaptic status and enabling early intervention before irreversible damage occurs.

The authors are careful to temper enthusiasm with caution. Most mechanistic evidence derives from in vitro studies and transgenic rodent models, and direct clinical data linking these pathways to synaptic outcomes in human patients remain limited. Phytochemical-based strategies have yet to demonstrate consistent efficacy in clinical trials, and challenges including dose standardization, potential drug interactions—resveratrol and quercetin inhibit CYP450 enzymes, potentially altering the metabolism of warfarin and statins—and safety concerns at high doses must be addressed. No phytochemical has yet received global regulatory approval as a disease-modifying agent for Alzheimer’s disease. Still, the review’s synthesis makes a compelling case that the future of Alzheimer’s therapy lies not in attacking a single molecular target but in restoring the delicate balance of energy metabolism, cytoskeletal integrity, intercellular communication, and immune regulation that keeps synapses functioning. As the authors conclude, Alzheimer’s disease is a system failure, not the failure of a single target—and the tools to rebuild that system may already be growing in the garden.

Subject of Research: Synaptic damage and repair mechanisms in Alzheimer's disease and the neuroprotective potential of phytochemicals

Article Title: Mechanistic insights into the synaptic damage-repair and regeneration processes in neurodegenerative Alzheimer’s disease: phytochemicals as neuroprotective agents

Article References: Yadav, B., Gangwar, P., Kumari, K., Yadav, A., Rao, R., Kumar, K., Verma, H., Dhiman, M., & Mantha, A. K. (2026). Mechanistic insights into the synaptic damage-repair and regeneration processes in neurodegenerative Alzheimer’s disease: phytochemicals as neuroprotective agents. Frontiers in Synaptic Neuroscience, 18, Article 1835778. https://doi.org/10.3389/fnsyn.2026.1835778

Image Credits: AI Generated

DOI: 10.3389/fnsyn.2026.1835778

Keywords: Alzheimer's disease, synaptic dysfunction, mitochondrial dysfunction, phytochemicals, neuroinflammation, exosomes, tau pathology, amyloid-beta, NETosis, cytoskeletal remodeling, blood-brain barrier, neuroprotection

The investigation began with a high-resolution survey of the bladder tumor landscape. The team integrated four public single-cell RNA sequencing datasets covering five normal bladder and nineteen bladder cancer samples, annotating cells into ten distinct lineages. Within the malignant compartment, LRG1 expression was markedly elevated, and non-negative matrix factorization revealed a specific tumor subcluster defined by high LRG1 output. When the researchers projected the marker genes of these subclusters onto bulk RNA sequencing cohorts from The Cancer Genome Atlas and independent datasets, the LRG1 meta-program was significantly associated with poorer overall survival. Clinically, the signal was even more compelling: serum LRG1 concentrations were substantially higher in patients with hematogenous metastasis than in those without, and histological staining showed dense LRG1 accumulation precisely in the vascular niche of metastatic tumors, where it colocalized with the endothelial marker CD31 while mural cell coverage, marked by alpha-SMA, was conspicuously reduced.

To test whether LRG1 was merely a bystander or an active driver, the researchers turned to genetically engineered mice lacking the Lrg1 gene. When MB49 bladder cancer cells were implanted into these animals, both subcutaneous and orthotopic tumors grew significantly more slowly than in wild-type controls, and lung metastases in a tail-vein model were drastically attenuated. Crucially, the tumor vasculature itself underwent a transformation. Microvessel density fell while average vessel diameter increased, a morphological hallmark of so-called vascular normalization. Pericyte coverage of the vessel wall improved, basement membranes became continuous and uniform rather than fragmented, and scanning electron microscopy revealed a pronounced reduction in the intraluminal endothelial inclusions that riddle leaky, pathological microvessels. Notably, the knockout mice showed no macroscopic abnormalities in major organs, suggesting that LRG1 is a pathological rather than a housekeeping factor and may be a relatively safe therapeutic target.

The pivotal clue to the mechanism came from single-cell transcriptomics performed on tumors overexpressing LRG1. After quality control retained 13,454 high-quality cells, unsupervised clustering identified six major lineages, and subclustering of the neutrophil compartment revealed four distinct subpopulations. One of these, designated C1, scored dramatically higher for a gene signature associated with neutrophil extracellular traps, and its proportion was markedly enriched in LRG1-overexpressing tumors compared with controls. Independent analysis of human data reinforced the picture: a NET-associated neutrophil subset defined by expression of NCF2 was expanded in tumor tissue relative to adjacent normal tissue, and gene set variation analysis across three bulk RNA sequencing cohorts showed a strong positive correlation between the LRG1 tumor meta-program and the abundance of this NET-forming subset.

Functional experiments then established LRG1 as both a recruiter and an activator of neutrophils. Conditioned medium from LRG1-overexpressing bladder cancer cells attracted freshly isolated human neutrophils far more effectively than control medium, while LRG1 knockdown reversed the effect, and flow cytometry confirmed that these differences were not explained by altered neutrophil survival. In vivo, depleting neutrophils with an anti-Ly6G antibody abolished the tumor-promoting effect of LRG1 overexpression entirely. Serological measurements in patients told a consistent story: circulating levels of cell-free DNA, myeloperoxidase, and neutrophil elastase, all canonical markers of NETosis, were elevated in bladder cancer patients and correlated positively with LRG1, with cell-free DNA showing a correlation coefficient of 0.59. Most strikingly, recombinant human LRG1 alone was sufficient to induce NET formation in purified neutrophils, upregulating MPO and citrullinated histone H3, the molecular fingerprints of NETs.

What do these NETs actually do to the vasculature? The answer, according to the study, is a two-faced assault. In vitro, intact NETs accelerated endothelial tube formation, increasing total tube length, capillary-like structures, and junctional nodes, while simultaneously inducing hyperpermeability in endothelial monolayers as measured by fluorescent dextran flux across cell layers. Bladder cancer cells were physically trapped within NET networks, an adhesion that DNase I digestion completely abolished, and exposure to intact NETs significantly enhanced cancer cell migration. In mice, an LPS-induced model of systemic NETosis accelerated tumor growth, but co-administration of DNase I, which degrades the extracellular DNA scaffolds of NETs, abrogated this effect. Immunofluorescence confirmed that NET accumulation stripped mural cells from tumor vessels, and DNase I treatment restored pericyte coverage and vascular integrity, mirroring in reverse the normalization seen in Lrg1-deficient animals.

The deepest mechanistic insight concerns how an extracellular protein persuades a neutrophil to self-destruct into a NET in the sterile, metabolically stressed environment of a tumor. Using pull-down assays followed by mass spectrometry, the team identified annexin A2, or ANXA2, as a direct binding partner of LRG1, an interaction confirmed by co-immunoprecipitation in primary human neutrophils and engineered cell lines. Truncation mutant experiments pinpointed the leucine-rich repeat domain of LRG1, amino acids 93 through 282, as essential for this binding. ANXA2, it turns out, functions as a chaperone that ferries activated Akt, phosphorylated at serine 473, into mitochondria, and this trafficking depends on ANXA2’s own phosphorylation at tyrosine 24. LRG1 binding obstructed ANXA2 phosphorylation and abolished the mitochondrial accumulation of active Akt. Engineered phosphomimetic ANXA2-Y24D mutants restored mitochondrial Akt localization, whereas phospho-dead Y24A mutants worsened the damage.

The downstream consequences for neutrophil metabolism were catastrophic. Recombinant LRG1 treatment triggered a massive surge in mitochondrial reactive oxygen species, a reduction in mitochondrial mass, severe depolarization of the mitochondrial membrane potential, and compromised ATP synthesis. Transmission electron microscopy provided direct visual confirmation: mitochondria in LRG1-treated neutrophils displayed swollen organelles, electron-dense matrices, and disorganized cristae, ultrastructural aberrations that the ANXA2-Y24D mutant partially ameliorated. This places the study squarely within an emerging paradigm in which mitochondrial, rather than purely cytosolic, reactive oxygen species drive NETosis, oxidizing mitochondrial DNA to yield highly immunogenic and pro-angiogenic extracellular traps. In effect, LRG1 acts as a metabolic reprogramming factor that short-circuits the energy machinery of innate immune cells, converting them into agents of vascular destruction.

The translational implications may prove the most consequential part of the story. In a retrospective cohort of twenty-nine bladder cancer patients treated with neoadjuvant cisplatin plus PD-1 blockade, non-responders showed synchronous upregulation of both LRG1 and the NET marker H3Cit, with nine of twelve non-responders classified as LRG1-high and ten of twelve as NETs-high, compared with far lower proportions among responders whose baseline characteristics were otherwise balanced. In mice, Lrg1 deficiency synergized with both cisplatin and anti-PD-1 therapy independently: cisplatin-treated knockout tumors showed increased DNA double-strand breaks and apoptosis, indicating deeper drug penetration, while anti-PD-1-treated knockout mice displayed augmented infiltration of CD8-positive cytotoxic T cells expressing elevated levels of Granzyme B. The authors propose that the LRG1-ANXA2-NETosis axis likely cooperates with the known endothelial TGF-beta/ALK1 pathway, jointly explaining the profoundly disorganized vasculature of bladder cancer, and they acknowledge that questions remain, including the functional role of tumor-specific glycosylation of LRG1 and the need for neutrophil-specific PAD4 knockout models to provide definitive genetic evidence. If those questions are answered, dismantling this axis could convert therapy-refractory, vessel-chaotic tumors into ones that drugs and immune cells can finally reach.

Subject of Research: LRG1-driven neutrophil mitochondrial dysfunction and NETosis in bladder cancer angiogenesis

Article Title: LRG1 Drives Pathological Angiogenesis by Disrupting Neutrophil Mitochondrial Homeostasis in Bladder Cancer

Article References: Chen, D., Zhang, C., Xue, S., Zeng, Y., Cui, H., Wang, C., Feng, J., Yan, L., & Zang, Y. (2026). LRG1 Drives Pathological Angiogenesis by Disrupting Neutrophil Mitochondrial Homeostasis in Bladder Cancer. Advanced Science, 13(56), Article e76604. https://doi.org/10.1002/advs.76604

Image Credits: AI Generated

DOI: 10.1002/advs.76604

Keywords: bladder cancer, LRG1, angiogenesis, neutrophil extracellular traps, NETosis, mitochondrial reactive oxygen species, ANXA2, vascular normalization, tumor microenvironment, single-cell RNA sequencing, immunotherapy resistance, pericyte coverage

Polymorphonuclear neutrophils, or PMNs, are the vanguard of the innate immune system. They patrol the bloodstream and rush to sites of infection or injury, guided by exogenous chemotactic factors such as bacterial formyl-methionyl-leucyl-phenylalanine, known as fMLP, and by endogenous cytokines including tumor necrosis factor alpha, interleukin-1, and interleukin-8. Once they arrive, they deploy an arsenal of antimicrobial weapons: the respiratory burst, in which the enzyme NADPH oxidase generates a storm of reactive oxygen species, and the formation of neutrophil extracellular traps, web-like lattices of chromatin that ensnare bacteria. Their movements and activation states are choreographed by surface molecules such as CD11b, part of the integrin Mac-1 that drives migration into inflamed tissue; CD66b, a hallmark of neutrophil activation; and CD62L, the l-selectin that facilitates exit from the bloodstream.

In autoimmune conditions such as rheumatoid arthritis and psoriasis vulgaris, these same defense mechanisms turn against the host. For years, research into these diseases concentrated on the adaptive immune system, the domain of T and B lymphocytes. More recently, attention has shifted toward neutrophils and their capacity for reactive oxygen species generation and NETosis, both of which appear central to disease pathogenesis. Yet these conditions remain difficult to treat, and methotrexate remains one of the most important therapeutic options in rheumatoid arthritis. The drug is a competitive inhibitor of dihydrofolate reductase, blocking DNA synthesis by preventing the conversion of dihydrofolate to its active form, tetrahydrofolate. But that canonical mechanism cannot fully explain its clinical effects, since methotrexate also influences cells with low proliferative rates, including terminally differentiated neutrophils.

The research team, working at the University of Regensburg, designed their experiments around a critical methodological insight from their own prior work: the standard practice of isolating neutrophils by centrifugation markedly impairs the cells’ function, compromising migration and antigen expression, apparently because granule contents are released inside the cells during the spin. To avoid this artifact, the researchers used a gentle sedimentation approach in which whole blood was mixed with a gelatin-based sedimentation agent and left to stand, allowing red blood cells to settle while a leukocyte-rich plasma layer was collected without centrifugation of the cells themselves. Blood was drawn from healthy volunteer donors under ethical approval, yielding samples from seventeen participants, nine male and eight female, aged 22 to 59, all healthy at the time of collection.

The centerpiece of the study was a three-dimensional chemotaxis assay conducted in microfluidic-style slides from Ibidi, each containing chamber systems with two reservoirs connected by a narrow channel. The chambers were filled with a type I collagen matrix mixed with culture medium containing methotrexate at concentrations of zero, 0.5, or 5 millimoles per liter, and neutrophils suspended in fifty percent autologous plasma were introduced on one side. On the opposite side, the researchers placed either fMLP at 10 nanomolar or interleukin-8 at 100 nanograms per milliliter to establish a chemotactic gradient. The entire setup was mounted on a Leica DMi8 inverted microscope inside a climate chamber holding conditions at 37 degrees Celsius, five percent carbon dioxide, and fifty percent humidity. Over an observation period of nearly 22 hours, the camera captured one image every 30 seconds, producing roughly 2,600 images per channel.

Cell tracking was performed with Imaris software, which assigned each cell a position within a coordinate system and followed it across 60 consecutive images, corresponding to 30-minute windows. The analysis yielded several parameters, including total track length, displacement along the axis of the chemotactic gradient, and track straightness. The results were striking. With fMLP as the attractant, the median track length fell from 373.0 micrometers in untreated cells to 296.3 micrometers at 0.5 millimoles per liter methotrexate and 214.7 micrometers at 5 millimoles per liter, differences that were highly significant. But the most dramatic effect appeared in directional movement: median displacement along the gradient axis collapsed from 87.2 micrometers in controls to 45.2 and then just 11.0 micrometers at the higher concentrations. At 5 millimoles per liter, total track length retained 57.6 percent of its baseline value, yet directional displacement fell to a mere 12.6 percent.

The same pattern emerged when interleukin-8 replaced fMLP, ruling out a specific interaction between methotrexate and a single chemoattractant. Median track lengths declined from 350.7 to 326.0 and then 237.7 micrometers across the concentration series, while gradient-directed displacement plummeted from 69.5 to 50.8 and finally 10.3 micrometers, all differences statistically significant. The interpretation is subtle but important: neutrophils exposed to methotrexate continue to move, but they largely lose their compass. The drug appears to interfere with the cells’ ability to sense or respond to a chemoattractant gradient, leaving them to wander in uncoordinated, non-directional paths. Notably, the inhibitory effect on migration appeared within just a few hours, far too quickly to be explained by impaired nucleotide synthesis, since neutrophils are terminally differentiated cells with minimal de novo synthetic capacity and highly restricted transcriptional activity.

Flow cytometry experiments painted a complementary picture. The researchers incubated leukocyte-rich plasma with methotrexate at four concentrations, 0, 0.005, 0.5, and 5 millimoles per liter, chosen to span clinically relevant exposures, since low-dose regimens for rheumatoid arthritis produce micromolar plasma levels while high-dose protocols for osteosarcoma can exceed 1.5 millimoles per liter. After 60 and 240 minutes, they measured the oxidative burst using the fluorescent dye dihydrorhodamine-123 and quantified surface epitopes with fluorophore-conjugated antibodies. The activation markers CD11b, CD62L, and CD66b showed no significant changes at either time point, indicating that methotrexate neither activates nor deactivates the cells in a conventional sense. Likewise, neither reactive oxygen species production nor NETosis differed between treated and control cells, a finding consistent across both microscopy and flow cytometry, though it contrasts with an earlier study reporting reduced ROS output in neutrophils from methotrexate-treated rheumatoid arthritis patients.

The one surface molecule that did respond was LOX-1, a receptor for oxidized low-density lipoprotein known primarily from endothelial cells and macrophages but recently identified on neutrophils, where it appears to exert an immunomodulatory and potentially immunosuppressive function. LOX-1 has been proposed as a biomarker of disease activity in rheumatoid arthritis, which makes the new finding particularly consequential. After 60 minutes of incubation, LOX-1 expression at 5 millimoles per liter methotrexate reached a mean fluorescence of 145.4, significantly higher than at 0.005 and 0.5 millimoles per liter. At 240 minutes, the effect was even clearer: expression at 5 millimoles per liter was significantly elevated compared with all three lower concentrations. This means that not only rheumatoid arthritis itself but also methotrexate treatment can drive LOX-1 upregulation, raising the question of how the two factors interact in patients and whether LOX-1 measurements must be interpreted in light of therapy.

The authors are careful to note the limitations of their work. Donor-to-donor variability may have influenced the results, the in vitro assays cannot be directly extrapolated to the living body, and the experiments used neutrophils from healthy donors rather than patients with inflammatory disease, whose cells may respond differently. The chemotaxis and flow cytometry data are also largely descriptive, and the molecular mechanism behind the loss of directional sensing remains unknown. Even so, the study delivers a coherent message: methotrexate selectively disarms neutrophil chemotaxis while leaving cell viability, activation markers, ROS production, and NETosis untouched, and it concurrently raises LOX-1 expression. For a drug that has been a clinical mainstay since the 1980s yet whose full mechanism of action has never been entirely pinned down, the demonstration that it can strip immune cells of their navigational sense, independent of which chemoattractant is calling them, opens a promising avenue for understanding both the drug’s anti-inflammatory power and the biology of the cells it targets.

Subject of Research: The immunomodulatory effects of methotrexate on neutrophil chemotaxis, surface marker expression, and LOX-1 upregulation

Article Title: Methotrexate Modulates Polymorphonuclear Neutrophil Function Through Reduced Chemotaxis and Increased LOX‐1 Expression

Article References: Wieke, V., Kraus, R. F., Gruber, M. A., & Kieninger, M. (2026). Methotrexate Modulates Polymorphonuclear Neutrophil Function Through Reduced Chemotaxis and Increased LOX‐1 Expression. Immunity, Inflammation and Disease, 14(10), Article e70537. https://doi.org/10.1002/iid3.70537

Image Credits: AI Generated

DOI: 10.1002/iid3.70537

Keywords: methotrexate, neutrophils, chemotaxis, LOX-1, rheumatoid arthritis, autoimmune disease, innate immunity, flow cytometry, live-cell imaging, reactive oxygen species, NETosis, CD11b

The research, led by teams at the University of Florence and the University of Pisa with international collaborators, focused on neutrophil extracellular traps, or NETs. NETs are web-like structures composed of DNA studded with toxic proteins that neutrophils normally release to immobilize and kill microbes. In recent years, however, biologists have recognized that inappropriate or excessive NET formation, a process called NETosis, contributes to autoimmune conditions, thrombosis and cancer progression. Earlier work had hinted that NETs are present in endometriotic lesions, but the molecular consequences of their presence, and the mechanisms that sustain their production in this disease, remained poorly defined.

To close that gap, the investigators first examined tissue from patients. Using immunofluorescence and immunohistochemistry, they compared endometriotic lesions from ten women with endometrial tissue from ten healthy controls. The lesions showed a marked increase in markers of NETs, including myeloperoxidase, an enzyme packaged into NET webs, and citrullinated histone H3, a chemical signature of the chromatin decondensation that precedes NET release. Masson’s trichrome staining, which dyes collagen blue, revealed significantly greater collagen deposition in the lesions, confirming that fibrosis accompanies the accumulation of these neutrophil-derived structures. The two phenomena, NET burden and scarring, appeared side by side in the same tissue.

The next question was whether the NETs were merely a bystander or an active driver of fibrosis. To find out, the researchers treated human endometriotic epithelial cells and stromal cells, the two main cell types within lesions, with isolated NETs in the laboratory. The response was striking. Epithelial cells underwent epithelial-mesenchymal transition, a developmental program in which tightly adherent epithelial cells lose their identity, gain motility and acquire the capacity to deposit extracellular matrix; this was visible as a loss of E-cadherin and a gain of mesenchymal markers. Stromal cells, meanwhile, shifted toward a myofibroblast-like phenotype, upregulating alpha-smooth muscle actin and fibronectin, hallmarks of activated, matrix-producing cells. In both compartments, NET exposure pushed the cells toward a pro-fibrotic state.

The mechanistic heart of the study lies in a lipid called sphingosine 1-phosphate, or S1P. S1P is a bioactive sphingolipid metabolite that signals through five cell-surface receptors and regulates immunity, vascular integrity and cell survival. The team found that when endometriotic cells were exposed to NETs, they reprogrammed their entire S1P signaling axis. Expression of sphingosine kinase-1, or SK1, one of the two enzymes that synthesize S1P, increased, as did the transporter Spns2, which exports S1P out of the cell, and two of the S1P receptors, S1P2 and S1P3. In other words, the cells not only made more of the lipid but also built the machinery to ship it out and to sense it once it returned.

To test whether this lipid circuit was actually responsible for the fibrotic response, the researchers used genetic silencing and pharmacological tools to interfere with SK1 or with Spns2. When either node of the pathway was disabled, the pro-fibrotic effect of NETs on endometriotic cells was abolished. This loss-of-function result is critical: it demonstrates that S1P synthesis and export are not incidental correlates of scarring but necessary links in the chain connecting neutrophil traps to collagen-producing behavior. The finding elevates S1P metabolism from a general inflammatory marker to a specific, testable driver of endometriosis-associated fibrosis.

Perhaps the most compelling discovery emerged when the direction of communication was reversed. The team collected conditioned media, the nutrient fluid in which endometriotic cells had been cultured, from cells in which S1P metabolism or export had been modulated, and applied these fluids to fresh neutrophils. The media potently influenced NETosis, showing that endometriotic cells stimulate neutrophils to release their traps through S1P-dependent signaling. Combined with the earlier results, this establishes a bidirectional feedback loop: neutrophils release NETs, which push endometriotic cells to produce and export S1P, and the exported S1P in turn drives neutrophils to form more NETs. Each turn of the loop amplifies both inflammation and fibrogenesis, providing a mechanistic explanation for why endometriotic lesions tend to become progressively more fibrotic over time.

To determine whether this circuit operates in the whole organism rather than only in culture dishes, the researchers measured circulating levels of S1P and myeloperoxidase, a NET marker, in the plasma of thirty patients and twenty healthy controls. In patients with endometriosis, the two molecules correlated positively, whereas in healthy women no such relationship existed. This correlation suggests that the S1P-NET axis is active systemically in the disease and raises the possibility that the pair could serve as a blood-based biomarker, offering a less invasive way to assess disease activity than surgery, which remains the gold standard for diagnosis today.

The therapeutic implications are considerable. Because the loop requires S1P synthesis by SK1 and its export through Spns2, both enzymes represent concrete points of intervention. Drugs that modulate S1P signaling already exist in other fields; fingolimod, a functional S1P receptor modulator, is an approved treatment for multiple sclerosis, and SK inhibitors are in development for cancer and inflammation. The present study does not report clinical trials of such agents in endometriosis, but it provides the preclinical rationale for evaluating them. Importantly, targeting S1P metabolism would be a non-hormonal strategy, addressing a major unmet need for patients who cannot tolerate or do not respond to existing hormonal therapy, and it could in principle dampen both NETosis and fibrogenesis simultaneously rather than merely suppressing lesion growth.

Caveats remain, as they do in any translational study. The patient tissue cohort was small, with ten lesions and ten controls in the histological analysis, and the plasma correlation, while statistically meaningful, does not by itself prove causation in humans. The mechanistic work relies on immortalized cell lines and isolated neutrophils, which capture key features of the disease but not its full complexity. Nonetheless, the convergence of patient tissue data, cell-based loss-of-function experiments and circulating biomarker correlations forms an unusually coherent evidence chain. The study also carries a poignant note: it is dedicated to the memory of co-author Asgerally T. Fazleabas, a distinguished reproductive biologist at Michigan State University who contributed to the project before his death. If future work confirms that breaking the S1P-NET loop slows fibrosis in patients, this research may mark the beginning of a shift in how endometriosis is understood, from a primarily hormonal disorder to one in which immune-lipid crosstalk is a central, and druggable, engine of disease progression.

Subject of Research: The role of sphingosine 1-phosphate signaling and neutrophil extracellular traps in fibrosis associated with endometriosis

Article Title: Sphingosine 1-phosphate-driven interplay between neutrophils and endometriotic cells fuels fibrosis in endometriosis: insights into the role of neutrophil extracellular traps

Article References: Prisinzano, M., Seidita, I., Bertilacchi, M. S., Giusti, M., Romeo, L., Nardi, E., Castiglione, F., Schumacher, F., Thomas, D., Kleuser, B., Fambrini, M., Fazleabas, A. T., Petraglia, F., Trincavelli, M. L., Bruni, P., Donati, C., Giacomelli, C., & Bernacchioni, C. (2026). Sphingosine 1-phosphate-driven interplay between neutrophils and endometriotic cells fuels fibrosis in endometriosis: insights into the role of neutrophil extracellular traps. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-08971-9

Image Credits: AI Generated

DOI: 10.1186/s12967-026-08971-9

Keywords: endometriosis, neutrophil extracellular traps, NETosis, sphingosine 1-phosphate, sphingosine kinase-1, Spns2, fibrosis, epithelial-mesenchymal transition, myeloperoxidase, inflammation, non-hormonal therapy, biomarkers

NETosis is a relatively recent addition to the immunology lexicon. First recognised as a mechanism for trapping and killing microbes, it involves the formation of neutrophil extracellular traps, or NETs, which are web-like lattices of DNA studded with antimicrobial proteins. The process can unfold in two distinct ways. In vital NETosis, the neutrophil remains alive and functional while deploying its DNA weapon, typically in response to pathogen-associated molecular patterns derived from microbes. In suicidal or lytic NETosis, the cell perishes: its nuclear envelope disintegrates, its plasma membrane ruptures, and DNA chains decorated with citrullinated histones, neutrophil elastase and myeloperoxidase spill into the extracellular space. The molecular choreography is intricate. An enzyme called peptidyl-arginine deiminase 4 citrullinates histones, loosening the grip of chromatin, while granule enzymes translocate to the nucleus to cleave histones further, allowing the genetic material to decondense before its dramatic release.

Although NETosis has been implicated in atherosclerosis and thromboinflammation, its role in chronic heart failure remained underexplored. The research team, led by Sawa Kostin and colleagues, examined left ventricular tissue from 21 patients undergoing orthotopic heart transplantation. The patients fell into three groups matched for age, symptom severity, medication and comorbidities: seven with inflammatory cardiomyopathy following histologically proven myocarditis, seven with idiopathic dilated cardiomyopathy, and seven with ischaemic cardiomyopathy caused by severe coronary artery disease. Crucially, in the ischaemic group the researchers analysed only tissue remote from previous infarcts, ensuring that observed inflammation reflected the failing heart as a whole rather than scarred regions. As controls, they used myocardial samples from five patients with aortic stenosis whose left ventricular function was fully preserved and whose tissue showed no damage, inflammation or fibrosis.

The results were striking. Using immunolabelling for CD66b, a neutrophil marker, the team found that control myocardium contained a median of just 2.48 neutrophils per square millimetre. In the failing hearts, that figure soared to 11.4 cells in dilated cardiomyopathy, 13.9 in ischaemic cardiomyopathy and 15.5 in inflammatory cardiomyopathy, a four- to six-fold increase. To detect NETosis directly, the researchers stained for citrullinated histone 3 and myeloperoxidase, two molecular signatures of NET formation. Confocal microscopy revealed thin, long NET structures, ranging from 5 to 50 micrometres, positive for both DNA and citrullinated histone 3, weaving through the failing myocardium. No such structures appeared in control tissue.

Biochemical and molecular assays corroborated the microscopy. Western blot analysis showed that citrullinated histone 3 protein levels were 4.8-fold higher in inflammatory cardiomyopathy, 4.4-fold higher in ischaemic cardiomyopathy and 2.7-fold higher in dilated cardiomyopathy compared with controls, with all differences statistically significant. Quantitative polymerase chain reaction confirmed that myeloperoxidase messenger RNA was three to four times more abundant in the failing hearts. When the researchers counted neutrophils positive for both CD66b and citrullinated histone 3, they found medians of 7.94 cells per square millimetre in inflammatory cardiomyopathy, 5.51 in dilated cardiomyopathy and 5.79 in ischaemic cardiomyopathy, against just 1.12 in controls. Triple staining for CD66b, citrullinated histone 3 and myeloperoxidase revealed a 4.6- to 6.1-fold increase across all heart failure groups, with no significant differences between aetiologies.

Macrophages told an equally compelling story. These highly plastic cells, which can polarise into classically activated M1-like macrophages that drive inflammation or alternatively activated M2-like macrophages that promote repair and phagocytosis, are among the most active immune participants in cardiac remodelling. Counting CD68-positive cells, the team found a median of 13.3 macrophages per square millimetre in control myocardium, rising to 47.1 in dilated cardiomyopathy, 55.4 in ischaemic cardiomyopathy and 69.4 in inflammatory cardiomyopathy. Remarkably, macrophage numbers correlated very strongly with neutrophil counts, with a Spearman coefficient of 0.918, suggesting the two cell populations accumulate in lockstep within the diseased heart.

Phenotyping revealed a decisive shift. In control tissue, only about 3 percent of macrophages displayed the M1-like profile, identified by co-expression of CD68 with tumour necrosis factor alpha or interleukin-6, while roughly 6.5 percent were M2-like, marked by CD206 or arginase-1. In the failing hearts, M1-like macrophages dominated: 78.5 percent in inflammatory cardiomyopathy, 54.5 percent in ischaemic cardiomyopathy and 53.2 percent in dilated cardiomyopathy. M2-like macrophages also increased, reaching roughly 21 to 23 percent, but never matched the proinflammatory surge. The resulting M1-to-M2 ratio, a measure of inflammatory balance, stood at 3.19 in inflammatory cardiomyopathy and around 2.5 to 2.6 in the other groups, compared with just 0.63 in controls, all differences statistically significant.

The pivotal finding emerged when the researchers correlated NETosis with macrophage polarisation. The percentage of M1-like macrophages correlated positively and significantly with the number of neutrophils undergoing NETosis, with a correlation coefficient of 0.79 for triple-positive citH3/MPO/CD66b cells and 0.68 for citH3/CD66b cells. In contrast, M2-like macrophages showed no meaningful association with NETosis, with coefficients near zero and non-significant p-values. Triple immunolabelling for citrullinated histone 3, tumour necrosis factor alpha and CD206 provided visual confirmation: NET-forming neutrophils were consistently surrounded by far more TNF-alpha-positive M1-like macrophages than CD206-positive M2-like cells.

What might this interplay mean mechanistically? Prior work offers intriguing clues. Co-culture experiments have shown that both M1- and M2-like macrophages can degrade NETs, with M1-like cells dominating the early phagocytic response and M2-like cells completing clearance later. Studies in acute pulmonary ischaemia-reperfusion injury have described a mutual feedback loop in which NETosis drives M1-like polarisation, which in turn promotes further NETosis. The authors suggest that in chronic heart failure this reciprocal interaction may create a positive feedback loop that sustains low-grade myocardial inflammation, a recognised hallmark of the disease. Alternatively, the M1 skewing could represent a compensatory attempt to clear excessive NETs, one that fails to suppress NET formation itself. The concurrent rise in M2-like macrophages, albeit more modest, may reflect involvement in clearing dead cardiomyocytes and contributing to fibrosis, given that the failing heart loses an estimated 20 percent of its cardiomyocytes each year in terminal stages.

The authors are careful to note that correlation does not establish causation, and that the observed associations may be consequences of chronic heart failure rather than drivers of it. The study’s limitations include the small number of patients, the differing aetiologies across groups and considerable interindividual variability. Nevertheless, the consistency of the findings across inflammatory, dilated and ischaemic forms of the disease, and the earlier observation that neutrophil and macrophage accumulation precedes overt heart failure in compensated hypertrophy, lend weight to the idea that this immune axis matters. Recent research also implicates extracellular vesicles released by injured cardiomyocytes in promoting neutrophil-driven inflammation and macrophage polarisation, suggesting multiple routes by which tissue damage could ignite the NETosis-macrophage circuit. If future studies confirm a causal role, inhibiting NETosis or restoring the balance between M1- and M2-like macrophages could become genuine therapeutic strategies for chronic heart failure, a condition that still lacks treatments targeting its inflammatory underpinnings. For now, the study provides a rigorous anatomical and molecular map of that circuit in human tissue, and a clear hypothesis for the next generation of experiments.

Subject of Research: The association between neutrophil extracellular trap formation and proinflammatory macrophage polarisation in human heart failure

Article Title: Increased NETosis in Patients With Heart Failure Is Associated With Macrophage Activation Towards a Proinflammatory Phenotype

Article References: Kostin, S., Cabrera‐Fuentes, H. A., Richter, M., Krizanic, F., Ritter, O., Boisvert, W. A., Preissner, K. T., Kelesidis, T., Siasos, G., & Pagonas, N. (2026). Increased NETosis in Patients With Heart Failure Is Associated With Macrophage Activation Towards a Proinflammatory Phenotype. Journal of Cellular and Molecular Medicine, 30(17), Article e71306. https://doi.org/10.1111/jcmm.71306

Image Credits: AI Generated

DOI: 10.1111/jcmm.71306

Keywords: heart failure, NETosis, neutrophils, macrophages, M1 polarisation, myocardial inflammation, citrullinated histone 3, myeloperoxidase, cardiac remodelling, innate immunity, cardiomyopathy, immunohistochemistry

The new particles, described in Bioengineering & Translational Medicine, were created by researchers at the University of Michigan who wanted to solve a persistent problem in corticosteroid therapy. Dexamethasone has shown real promise in recent clinical trials for ARDS, improving outcomes where older steroids failed. Yet those benefits typically require high doses over prolonged regimens, and they appear limited to certain patient subgroups, with some patients actually faring worse after treatment. Free dexamethasone circulating through the bloodstream also triggers well-documented systemic effects, including neutrophilia, an abnormal rise in blood neutrophil counts, and lymphopenia, the depletion of lymphocytes. The Michigan team reasoned that if the drug could be packaged so that it preferentially reached neutrophils themselves, the therapeutic effect would be concentrated at the source of tissue damage while the rest of the body would be spared.

The fabrication strategy is elegantly simple. The researchers added an iron sulfate solution dropwise into a stirred solution of dexamethasone phosphate, triggering a nucleation-and-growth process in which amorphous iron-phosphate particles form with dexamethasone incorporated throughout the particle matrix. The resulting nanoparticles, dubbed Dex NP, measured approximately 75 nanometers in diameter with a zeta potential between negative 10 and negative 20 millivolts. Scanning electron microscopy confirmed uniform particle morphology, and energy-dispersive X-ray spectroscopy mapping showed that iron and dexamethasone phosphate were evenly distributed across each particle rather than segregated into layers. There was just one problem: when these first-generation particles were incubated with human neutrophils in whole blood, the cells ignored them completely. No internalization occurred, which meant the drug delivery concept would fail before it even left the bench.

The breakthrough came from reconsidering the particle surface. Nanoparticle behavior in blood is governed largely by the protein corona, the layer of plasma proteins that adsorbs onto the particle within seconds of exposure. Albumin, the most abundant plasma protein, is a known dysopsonin, meaning its presence on a particle surface actively discourages phagocytes from engulfing it. The team hypothesized that the ionic iron within the particle matrix could be exploited to change the surface chemistry. Because iron oxide can form at temperatures as low as 200 degrees Celsius in open air, the researchers heated their particles to 200, 215, and 230 degrees and monitored how the protein corona changed. Only temperatures above 215 degrees altered protein adsorption, so 215 degrees became the standard oxidation step, transforming Dex NP into DexOx NP.

Characterization confirmed the transformation worked exactly as intended. X-ray photoelectron spectroscopy of the top 10 nanometers of the particle surface revealed a shift from ferrous to ferric iron, consistent with iron oxide formation, while Fourier transform infrared spectroscopy showed that the characteristic peaks of dexamethasone phosphate survived the heating intact. This mattered because dexamethasone begins to thermally degrade only above 200 degrees Celsius, with degradation onset at 256 degrees under controlled heating rates, and the brief oxidation window used here was measured in minutes rather than the hour-long exposures that have degraded the drug in prior polymer studies. Release assays in phosphate-buffered saline at physiological temperature showed that dexamethasone emerging from the particles remained as therapeutically active as the free drug, confirming the payload was not compromised during manufacturing.

The biological consequences of oxidation were striking. When FITC-labeled particles were incubated in whole human blood and mouse blood, flow cytometry showed a distinct fluorescence shift in the neutrophil population for DexOx NP but not for the unoxidized particles, and confocal microscopy visualized the oxidized particles sitting inside neutrophils. Protein corona analysis explained why: total adsorbed protein dropped after oxidation, with marked reductions in the albumin and transferrin bands at roughly 60 and 80 kilodaltons, proteins known to adsorb poorly to iron oxide. Meanwhile, a slight increase in bands between 150 and 200 kilodaltons suggested immunoglobulins, which activate complement and drive phagocytosis, had taken their place. Less albumin blocking the surface and more immunoglobulin flagging the particle combined to make DexOx NP irresistible to neutrophils.

Safety testing came next, and the particles passed cleanly. DexOx NP caused no hemolysis of red blood cells, did not activate platelets, and left unactivated neutrophils untouched, indicating the particles could be infused systemically without triggering the very inflammation they were designed to treat. In activated neutrophils, however, the therapeutic effect was dramatic. When lipopolysaccharide was used to simulate bacterial activation, DexOx NP preserved L-selectin, an adhesion molecule shed during neutrophil activation, reducing shedding by 68 percent. This outperformed both free dexamethasone phosphate and the poorly internalized Dex NP, neither of which changed L-selectin expression at all. The effect depended on the glucocorticoid receptor, since mifepristone, a receptor antagonist, blunted the benefit, and control experiments with plain iron oxide particles confirmed the activity came from the dexamethasone rather than the metal.

The particles also tamed NETosis, the explosive process by which activated neutrophils expel DNA and intracellular contents, which drives tissue damage in ARDS. In neutrophils stimulated with phorbol 12-myristate 13-acetate, DexOx NP reduced total NET formation by 21 percent over five hours, while free dexamethasone phosphate, unoxidized particles, and cargo-free polystyrene particles had no effect. The mechanism likely involves inhibition of NADPH oxidase, the enzyme complex that initiates NET formation and whose p47phox subunit is a known corticosteroid target. Because internalized particles release dexamethasone directly into the cytosol where the glucocorticoid receptor resides, the team suggests the intracellular delivery route accelerates and amplifies the drug’s action compared with diffusion of free steroid from the extracellular fluid.

The decisive test came in a mouse model of acute lung injury, where lipopolysaccharide was instilled into the airways and treatments were injected into the tail vein one hour later. Both DexOx NP and free dexamethasone significantly reduced immune cell infiltration into the lungs, cutting total bronchoalveolar lavage cells by 37 and 34 percent respectively and neutrophil counts by 41 and 39 percent. Both treatments lowered the inflammatory cytokines IL-6 and TNF-alpha, and DexOx NP significantly reduced KC, a chemokine that recruits neutrophils to inflamed tissue. Cargo-free polystyrene particles, which neutrophils also engulf, did nothing, proving the benefit came from the drug rather than from particle diversion alone. Crucially, the side-effect profiles diverged sharply: free dexamethasone raised blood neutrophil counts by 57 percent and increased the neutrophil-to-lymphocyte ratio by 64 percent, classic signs of systemic steroid exposure, while DexOx NP produced neither effect. Liver enzymes, leukocyte counts, and body weight remained normal in healthy mice given the particles.

The findings point toward a broader strategy for taming acute inflammation without the blunt instrument of systemic steroids. Because the particles are composed of iron and the drug itself, with no exogenous polymer carrier, they avoid the stability, reproducibility, and loading problems that plague conventional formulations such as liposomes and PLGA particles. The researchers, who have filed a patent on composite drug particles, note that the approach could extend beyond dexamethasone to other corticosteroids and inflammatory diseases driven by neutrophil dysregulation. For a condition like ARDS, where clinicians have long struggled to harness steroid power without immunological collateral damage, a nanoparticle that speaks directly to the immune system’s most volatile cells represents a meaningful step toward precision anti-inflammatory medicine.

Subject of Research: Targeted dexamethasone nanoparticles that modulate neutrophil activity to treat acute neutrophilic inflammation and acute lung injury

Article Title: Iron‐dexamethasone nanoparticles mitigate acute neutrophilic inflammation

Article References: Felder, M. L., Guevara, M. V., Kupor, D., & Eniola‐Adefeso, O. (2026). Iron‐dexamethasone nanoparticles mitigate acute neutrophilic inflammation. Bioengineering & Translational Medicine, Article e70173. https://doi.org/10.1002/btm2.70173

Image Credits: AI Generated

DOI: 10.1002/btm2.70173

Keywords: neutrophils, dexamethasone, nanoparticles, acute lung injury, ARDS, drug delivery, inflammation, NETosis, protein corona, iron oxide, corticosteroids, immunomodulation

The scale of neutrophil involvement in cancer is staggering. Neutrophils are the most numerous circulating leukocytes in humans, produced at a rate of roughly one hundred billion cells per day in the bone marrow, and they can constitute the dominant immune population within many solid tumors. Large-scale analyses of the tumor immune landscape across human cancers have repeatedly found that high intratumoral neutrophil content correlates with poor prognosis in numerous malignancies, including renal cell carcinoma, head and neck cancer and non-small cell lung cancer. The neutrophil-to-lymphocyte ratio, a simple blood measurement, has emerged as one of the most robust prognostic biomarkers in oncology, predicting outcomes across tumor types and even forecasting response to immune checkpoint inhibitors.

Why would the immune system’s first responders become cancer’s accomplices? The answer, the review argues, lies in the extraordinary plasticity of neutrophils and their exquisite sensitivity to environmental cues. Tumors are, in the words of a classic 1986 observation by Harold Dvorak, wounds that do not heal, and neutrophils are the cells that respond to wounds. Cancers exploit the same inflammatory programs that neutrophils deploy during tissue repair. Tumor-derived signals such as granulocyte colony-stimulating factor, transforming growth factor-beta, interleukin-8 and other chemokines reprogram both the production and the function of neutrophils, driving emergency granulopoiesis in the bone marrow and recruiting immature, immunosuppressive granulocytes into the circulation and the tumor bed.

Once inside the tumor microenvironment, neutrophils promote cancer through several mechanistically distinct pathways. They release vascular endothelial growth factor and, critically, matrix metalloproteinase-9, an enzyme that liberates sequestered VEGF from the extracellular matrix and triggers the angiogenic switch that transforms a dormant lesion into a growing tumor. Studies in mouse models of multistage carcinogenesis showed that infiltrating neutrophils mediate this initial angiogenic switch, and human neutrophils are unique in releasing MMP-9 free of its natural inhibitor TIMP-1, making it an especially potent driver of new blood vessel formation. Neutrophil elastase, another granule protease, can degrade insulin receptor substrate-1 in tumor cells to accelerate lung tumor growth, and myeloid cell-derived reactive oxygen species have been shown to induce mutagenesis in adjacent epithelial cells, directly fueling the genomic instability that drives malignant transformation.

Perhaps no neutrophil behavior has attracted more attention in recent years than the formation of neutrophil extracellular traps, or NETs. First described in 2004 as web-like structures of DNA, histones and granule proteins that ensnare bacteria, NETs have since been implicated in a remarkable range of tumor-promoting processes. Recent work published in Nature demonstrated that NETs drive vascular occlusion, tumor necrosis and metastasis, linking phenomena long thought to be independent. NETs can sequester circulating tumor cells, shielding them from cytotoxic lymphocytes and natural killer cells; NET-associated DNA can bind the receptor CCDC25 on cancer cells, directing their migration; and NETs produced during systemic inflammation can awaken dormant cancer cells, triggering metastatic relapse years after primary tumor removal. Strikingly, the metastatic spread of breast cancer has been shown to accelerate during sleep, when rhythmic fluctuations in circulating neutrophils and cancer cell dynamics converge.

Neutrophils also construct the pre-metastatic niche, the distant soil that primary tumors prepare to receive their disseminated seeds. Tumor-derived factors mobilize neutrophils and their progenitors to future metastatic sites, where they suppress natural killer cell activity, remodel the extracellular matrix and create an immunologically permissive environment. In breast cancer models, neutrophils support the lung colonization of metastasis-initiating cells, and chronic stress has been shown to increase metastasis through neutrophil-mediated changes to the microenvironment. Even glucocorticoids, widely used clinically, can promote breast cancer metastasis by acting on these cells. The circadian biology of neutrophils, governed by an intrinsic molecular timer that coordinates immune defense and vascular protection, adds another layer of complexity to how and when these cells enable metastatic spread.

Yet the story is emphatically not one-directional. The review devotes substantial attention to the antitumor capacities of neutrophils, which many of the same molecules can mediate depending on context. Neutrophil elastase, which promotes tumor growth in some settings, has been shown in other contexts to selectively kill cancer cells and attenuate tumorigenesis, with important differences between mouse and human neutrophils in the production of its inhibitor, secretory leukocyte proteinase inhibitor. Activated neutrophils exert direct cytotoxicity against melanoma cells through reactive oxygen species, and tumor-associated neutrophils in early-stage human lung cancer can stimulate T cell responses rather than suppress them. Tumor-entrained neutrophils have even been shown to inhibit metastatic seeding in the lung, providing early evidence of spontaneous antimetastatic function. The pro- versus antitumor polarization of neutrophils, famously framed as N1 versus N2 states, is now understood to reflect a continuum of environmentally determined functional states rather than fixed identities.

This dual nature is precisely what makes neutrophils such compelling therapeutic targets. The review highlights several promising strategies. Neutrophil-activating therapy, developed by the Stanford group, demonstrated that pharmacologically activated neutrophils can eradicate tumors and reduce metastases independently of adaptive immunity. CD40 agonist antibodies recruit a subset of neutrophils associated with tumor control, and T cell immunotherapies have been shown to engage neutrophils to eliminate antigen-escape variants that would otherwise survive checkpoint blockade. Bacille Calmette-Guerin, the century-old tuberculosis vaccine used to treat bladder cancer, works in part by reprogramming hematopoiesis so that neutrophils develop the capacity to attack tumor cells, and interferon-gamma induces NET formation with tumor-killing activity in colorectal cancer. On the inhibitory side, CXCR2 antagonists, peptidyl arginine deiminase 4 inhibitors that block NET formation, arginase inhibitors, and antibodies that block the NET-associated immunosuppressive enzyme arginase-1 are all in clinical development, several in combination with checkpoint inhibitors.

Antibody-based approaches represent another frontier. Neutrophils are extraordinarily potent mediators of antibody-dependent cellular cytotoxicity, and IgA antibodies in particular trigger superior neutrophil-mediated killing of cancer cells compared with conventional IgG, engaging the Fc-alpha receptor to produce vigorous respiratory bursts and trogoptosis, a process in which neutrophils progressively strip membrane fragments from antibody-coated targets. Combining IgA-based therapeutics with blockade of the CD47-SIRP-alpha innate immune checkpoint, which prevents phagocytosis, has shown enhanced neutrophil cytotoxicity against neuroblastoma and other malignancies. Even more ambitiously, researchers have engineered chimeric antigen receptor neutrophils derived from induced pluripotent stem cells, which possess potent activity against solid tumors and can serve as delivery vehicles for tumor-microenvironment-responsive nanodrugs in glioblastoma. Neutrophils bearing adhesive polymer micropatches have been proposed as a drug-free immunotherapy platform.

The authors caution that translating these findings into the clinic requires resolving fundamental questions about neutrophil heterogeneity, nomenclature and species differences. A consensus statement has established standards for myeloid-derived suppressor cell classification, and recent single-cell atlases have mapped neutrophil developmental trajectories across tissues and disease states, revealing that mature and immature neutrophils converge on similar transcriptional signatures within tumors. Human and mouse neutrophils differ in important ways, including their circadian rhythms, granule composition and lifespan, with human neutrophils surviving approximately five days rather than hours as once believed. Nevertheless, the convergence of mechanistic insight, biomarker validation and early clinical activity suggests that the field has reached an inflection point. Neutrophils, long dismissed as terminally differentiated foot soldiers, are now recognized as master regulators of the tumor ecosystem, and learning to command them, rather than simply deplete them, may define the next era of cancer immunotherapy.

Subject of Research: The roles of neutrophils in tumor progression, immunosuppression, metastasis and cancer therapy

Article Title: Neutrophils in cancer

Article References: Diehl, M. I., Basto, P. A., Abikenari, M. A., Linde, I. L., Okwan-Duodu, D., & Engleman, E. G. (2026). Neutrophils in cancer. Nature Reviews Cancer. https://doi.org/10.1038/s41568-026-00968-2

Image Credits: AI Generated

DOI: 10.1038/s41568-026-00968-2

Keywords: neutrophils, cancer, tumor microenvironment, neutrophil extracellular traps, metastasis, immunosuppression, angiogenesis, tumor-associated neutrophils, immunotherapy, myeloid-derived suppressor cells, NETosis, granulopoiesis

The mechanistic heart of the review is the positive feedback loop it describes between cancer cells, tumor-associated neutrophils and NETs. Tumor cells orchestrate the reprogramming of neutrophils through paracrine signaling: they secrete chemokines such as CXCL1 and CXCL2, which recruit neutrophils via the CXCR1 and CXCR2 receptors, and cytokines including IL-1β, IL-8, granulocyte colony-stimulating factor and tumor-derived exosomes carrying mutant KRAS. Once in the tumor microenvironment, these neutrophils can be pushed toward NET formation by hypoxia, acidity, collagen signaling through DDR1, and stromal inputs from cancer-associated fibroblasts. The NETs themselves then feed back on the tumor, activating pro-growth pathways such as ERK and NF-κB, promoting epithelial-mesenchymal transition and reinforcing the very signals that recruit more neutrophils. This self-amplifying circuit explains why circulating and tumor-infiltrating NETs correlate so consistently with advanced disease in breast, pancreatic, gastric, colorectal and hepatocellular cancers, among others studied to date.

At the molecular level, NET formation, or NETosis, is a carefully choreographed demolition of the neutrophil’s own architecture. In the classical suicidal pathway, signaling through reactive oxygen species generated by the NADPH oxidase complex activates protein arginine deiminase 4, or PAD4, an enzyme that hypercitrullinates histone H3. Citrullination loosens the electrostatic grip of histones on DNA, driving chromatin decondensation, nuclear envelope breakdown and ultimately the explosive extrusion of decondensed DNA decorated with granule proteins. Neutrophil elastase and myeloperoxidase translocate to the nucleus to assist this dismantling, while cathepsin G and proteinase 3 join the final trap. Alternative routes exist as well: viable neutrophils can expel mitochondrial DNA to form traps without dying, and rapid, nuclear-based release has been documented within minutes of certain bacterial encounters. Which pathway dominates appears to depend on the stimulus, a specificity confirmed by comparative proteomic analyses showing that NETs induced by different triggers carry distinct protein cargoes.

As weapons of metastasis, NETs act on several fronts simultaneously. Their DNA scaffolds physically enmesh circulating tumor cells in the bloodstream, increasing adhesion to the vascular endothelium and creating a protective nidus in which disseminated cells can extravasate and colonize distant organs. Proteases embedded in the traps, notably matrix metalloproteinase-9 and neutrophil elastase, remodel the extracellular matrix and, in pancreatic cancer, activate quiescent stellate cells and cancer-associated fibroblasts that prepare fertile ground for micrometastases. Landmark work in mice showed that NETs produced during inflammation can rouse dormant cancer cells, explaining recurrences years after primary tumor removal. The traps also subvert immunity directly: NET-associated DNA can bind TMCO6 on T cells to impair CD8-positive cytotoxic function, upregulate the immunosuppressive enzyme CD73, decorate themselves with PD-L1, promote T cell exhaustion and foster T regulatory cell infiltration. In this sense, NETs function as both physical scaffolds for spread and chemical camouflage against the immune system, a dual role that the review identifies as central to immune evasion and distant metastasis.

The consequences extend to treatment resistance, one of oncology’s most stubborn bottlenecks. NETs generated during chemotherapy confer resistance by activating latent TGF-β, while the dense DNA matrix limits the diffusion of drugs such as doxorubicin, blunting its ability to trigger apoptosis in ovarian cancer cells. In bladder cancer, NETs contribute to radiation resistance, and low-dose ionizing radiation itself can provoke NET extrusion, an unsettling feedback. Immune checkpoint blockade suffers too: NET formation driven by IL-17 signaling mediates resistance in pancreatic cancer, cirrhotic extracellular matrix initiates immunosuppressive NETs that attenuate anti-PD-1 responses in hepatocellular carcinoma, and IGF2BP3-induced NETosis undermines oncolytic virotherapy in malignant glioma. Conversely, the review emphasizes that targeted disruption of the NET axis reverses these resistances and sensitizes tumors to radiotherapy, chemotherapy and checkpoint inhibitors, positioning NETs as genuinely novel therapeutic targets rather than mere biomarkers of misfortune.

A notable theme of the review is the breadth of candidate drugs capable of disarming the NET machinery, many of them repurposed from other fields. Anthracyclines suppress both NADPH oxidase-dependent and -independent NETosis; the antiparasitic ivermectin abrogates NETs and prevents melanoma metastasis in preclinical models; chloroquine and hydroxychloroquine reduce trap formation partly by inhibiting PAD4; and the glucagon-like peptide-1 receptor agonists liraglutide and exenatide enhance checkpoint blockade efficacy by attenuating NETs in lung and liver cancers. Metformin mitigates obesity-driven NET-driven tumor aggressiveness in mice, the nuclear export inhibitor selinexor blocks human NET formation in vitro, and histidine-rich glycoprotein suppresses hepatic metastatic seeding. Even traditional Chinese medicine formulations, from Huang Qin Decoction to Pi Ji Pills, and phytochemicals such as kaempferol, resveratrol, epigallocatechin-3-gallate and emodin, have been shown to interfere with the ROS-PAD4, STAT3-CXCL8 and PI3K-AKT pathways that drive trap formation. Biomaterials approaches, including NET-degrading enzyme hydrogels applied after surgery, and localized photoregulated enzyme delivery, offer physically targeted ways to dismantle traps at metastatic sites.

Translating these discoveries into the clinic depends on measuring NETs reliably, and the review devotes substantial attention to detection technology. The most widely used circulating markers are cell-free DNA, nucleosomes, myeloperoxidase-DNA and neutrophil elastase-DNA complexes, and citrullinated histone H3, the latter quantified by increasingly refined enzyme-linked immunosorbent assays validated in human plasma. Flow cytometric assays allow direct enumeration of NET-bearing structures in blood, atomic force microscopy has resolved the physical architecture of individual traps, and microfluidic chips can capture chromatin fibers from a single drop of blood, while computational image-analysis algorithms now standardize histological quantification. Clinically, peripheral blood NET biomarkers have been associated with diagnosis and progression of malignant tumors, trap-associated CEACAM1 has been proposed as a therapeutic target in metastatic colon cancer, and PD-L1-positive neutrophils releasing NETs in malignant ascites show promise as a hepatocellular carcinoma biomarker. Gene-expression signatures built around NET-related genes and long non-coding RNAs predict prognosis and immunotherapy response across gastric, breast, colon, lung, head-and-neck and soft-tissue cancers, although the review cautions that inconsistent findings and tumor heterogeneity still constrain their deployment.

The prognostic potential is especially striking. Tumor-infiltrating NETs predict post-surgical survival in pancreatic ductal adenocarcinoma, blood NETosis correlates with progression in head and neck cancer, pan-cancer signatures built from NET-associated genes stratify patient outcomes, and a NET-score has emerged as a prognostic marker in colorectal cancer. NETs also influence cancer-associated thrombosis, a major cause of morbidity: tumor-derived exosomes induce NETs that establish hypercoagulability, and IL-1β blockade attenuates thrombosis in NET-dependent breast cancer models. Yet the review is candid about limitations. Detection technologies remain imperfect and poorly standardized, prognostic modeling must contend with heterogeneous patient populations, and some research findings conflict, reflecting context-dependent roles of neutrophil subsets that range from antitumor to pro-tumor. Aging itself alters NET biology, complicating extrapolation from young animal models to elderly patients. Future work, the authors argue, should prioritize optimizing detection methods, conducting rigorous clinical validation and identifying tumor-type-specific therapeutic targets.

The broader message is that the immune defense once celebrated for strangling microbes has become a central hub in cancer biology, one that links inflammation, dormancy, metastasis, thrombosis and treatment failure within a single mechanistic framework. By mapping the regulatory factors, from PAD4 and neutrophil elastase to CXCL chemokines and TGF-β, and by cataloguing both the pharmacological and biomaterial tools that can interrupt them, the review provides a theoretical basis for bringing NETs into precision oncology. If the technical and validation challenges can be overcome, clinicians may one day read a patient’s NET profile the way they now read hormone receptor status, and use NET-disrupting agents to prevent metastasis and sensitize tumors to the therapies already at hand. For now, the convergence of mechanistic insight, assay development and drug repurposing suggests that a web once woven for defense is becoming an actionable thread in the fight against cancer.

Subject of Research: Neutrophil extracellular traps in tumor progression, detection and diagnosis

Article Title: Neutrophil extracellular traps in tumor progression: from mechanistic insights and regulatory factors to clinical detection and diagnosis

Article References: Zhang, Y., Zeng, Z., Xiong, W., Luo, J., & Fan, C. (2026). Neutrophil extracellular traps in tumor progression: from mechanistic insights and regulatory factors to clinical detection and diagnosis. Journal of Molecular Medicine, 104(1), Article 104. https://doi.org/10.1007/s00109-026-02709-2

Image Credits: AI Generated

DOI: 10.1007/s00109-026-02709-2

Keywords: neutrophil extracellular traps, tumor-associated neutrophils, metastasis, immune evasion, therapy resistance, PAD4, cancer biomarkers, tumor microenvironment, diagnosis, checkpoint blockade, NETosis, precision oncology