Tissue-resident macrophages receive signals from their microenvironment that coordinate the activity of transcription factors (TFs) to establish distinct transcriptional profiles and identities. However, the molecular mechanisms whereby interactions with other cells of the niche imprint a distinct macrophage identity remain poorly understood. Here, we report that retinoid X receptors (RXRs) determine the differentiation and identity of alveolar macrophages (AM) by regulating chromatin accessibility and transcriptional activity of AM-core and function genes, enabling PPARγ-dependent programs. AM differentiation and maintenance in vivo require RXR upregulation in response to tissue-derived δ-like canonical Notch ligand 4 (DLL4), GM-CSF, and TGF β (TGFβ). Interplay among these signals leads to cooperation between RXRα, RBPJ, STAT5, and SMAD4 for the transcriptional and epigenetic regulation of key AM-core genes. These results underscore the role of RXRs as key TFs that cooperate with other regulatory elements to establish the AM population and determine AM identity.

Introduction Myocarditis is an inflammatory disease characterized by a wide spectrum of clinical presentations, which complicates its diagnosis and management. The Precision Biomarkers for Diagnosis and Management of Myocardial Inflammatory Diseases (Pre-MYO) project aims to address three major gaps: (i) the limited knowledge regarding the epidemiology, clinical management and prognosis; (ii) the absence of specific and widely accessible biomarkers able to provide an early diagnosis (precision medicine); (iii) the lack of biomarkers of susceptibility to myocarditis, including risk of recurrence and disease severity (personalized medicine).Study design The Pre-MYO is a prospective, observational and multicentre nationwide project designed to enrol 3000 patients with suspected myocarditis or inflammatory cardiomyopathy based on clinical findings. The registry includes extensive clinical characterization and long-term follow-up, including biobanks of blood samples, DNA, and cardiac magnetic resonance imaging (CMR). The platform will enable the investigation and validation of novel diagnostic and prognostic biomarkers, including the candidate hsa-RNA-Chr8:96, and the development of clinical trials. Predisposition studies will be conducted to investigate environmental and immune factors, genetic mutations, and acquired variants-including methylation analyses-that contribute to individual predisposition and risk.Discussion The Pre-MYO project will establish a collaborative research framework aimed at improving the understanding and clinical management of myocarditis by integrating precision and personalized medicine approaches.

BACKGROUND Excessive trabeculations and myocardial crypts are recurrent features across cardiomyopathies, yet their developmental origins and clinical significance remain poorly defined. To reveal the link between cardiac morphogenesis and disease, we generated humanized mouse models carrying patient-derived MYBPC3 frameshift mutations associated with overlapping hypertrophic cardiomyopathy (HCM) and left ventricular non-compaction (LVNC). METHODS We applied CRISPR-Cas9 to introduce distinct MYBPC3 frameshift alleles into the mouse genome and performed comprehensive phenotypic and transcriptomic profiling from fetal life through adulthood. RESULTS Adult homozygous Mybpc3 frameshift mutant mice like humans displayed hallmark HCM; however, without LVNC. Fetal and neonatal mutant hearts exhibited markedly enlarged ventricular trabeculae and crypts that progressed postnatally into the observed adult hypertrophy. Transcriptomic analysis revealed stage-specific dysregulation of oxidative metabolism, nonsense-mediated decay (NMD), and cell cycle pathways, peaking at postnatal days 1 and 7, indicating that these stages represent critical time points in disease onset. The persistent NMD signature, also observed in phenotype-negative heterozygotes, suggests a compensatory stress response. Enlarged trabeculae exhibited 2-fold increased trabecular cardiomyocyte proliferation, reversing the normal compact–trabecular proliferative gradient and leading to impaired ventricular compaction in neonates. Hey2 CreERT2 lineage tracing demonstrated invasion of Hey2 + compact cardiomyocytes into the trabeculae and ectopic trabecular expression of the Prdm16 transcription factor, indicating defective ventricular wall patterning and maturation. Postnatally, Hey2 + -derived cardiomyocytes became restricted to the outer/compact myocardium in mutants, while the inner/trabecular myocardium underwent accelerated hypertrophy concurrent with Prdm16 downregulation. Mice with a Mybpc3 missense variant also exhibited Hey2 + myocardial lineage expansion into trabeculae but no increased proliferation, implicating additional mechanisms beyond Hey2 regulation. Postnatal Prdm16 restoration, via transgenic expression in Mybpc3-null mice effectively attenuated hypertrophy, establishing a causal link between Mybpc3 loss, Prdm16 decline, and pathological remodeling. CONCLUSIONS Mybpc3 governs ventricular wall maturation by regulating cardiomyocyte proliferation, patterning, and maturation, partly via Prdm16. Disruption of these developmental programs precedes and drives adult HCM, highlighting a developmental role for sarcomeric proteins, and revealing postnatal Prdm16 modulation as an antihypertrophic therapeutic strategy.

Mavacamten is a targeted treatment for hypertrophic cardiomyopathy, a disease caused by genetic variants affecting mainly sarcomeric myosin and its regulator cardiac myosin-binding protein C (cMyBP-C, encoded by MYBPC3). Here we generate knock-in mice including missense pathogenic variant cMyBP-C p.R502W, which unlike carriers of cMyBP-C truncations, develop pathogenic myocardial remodeling with preserved cMyBP-C levels and localization. Mechanistically, R502W reduces cMyBP-C-myosin affinity and generates sarcomere hypercontractility due to increased Ca2+ sensitivity and a favored ON structural state of myosin. Even though these pathomechanisms do not overlap with those triggered by truncating MYBPC3 variants, mavacamten blunts myocardial remodeling both in R502W and cMyBP-C-deficient hearts, correlating with the drug's ability to restore OFF myosin in R502W sarcomeres. In R502W human engineered heart tissues, mavacamten also opposes hypercontractility. Hence, our results indicate that mavacamten is effective in treating hypertrophic cardiomyopathy caused by both truncating and missense MYBPC3 variants regardless of their primary pathomechanisms.

Despite intriguing roles for the Succinate receptor (Sucnr1) in inflammation, few studies have explored its role in hematopoiesis. Here, we show that low SUCNR1 represents a marker for reduced overall and progression-free survival in acute myeloid leukemia (AML) patients. Succinic acid, which displays Sucnr1-dependent and independent effects, promotes disease in mouse models of pre-leukemic myelopoiesis, AML and AML xenografts, expressing low SUCNR1. In vivo global or hematopoietic deletion of Sucnr1 induces expansion of hematopoietic stem and progenitor cells (HSPC) and hematopoiesis, whilst Sucnr1-tomato+ HSPC display restricted engraftment potential. Mechanistically, activation of Sucnr1 counterbalances the stimulatory effect of intracellular succinate in HSPC and preserves HSPC transcriptional programs via control of S100a8/S100a9. Blocking S100a9 with tasquinimod rescues the defects of Sucnr1 knock-out mice, and combined with a potent Sucnr1 agonist shows therapeutic value in AML mice. In AML xenografts, single-cell RNA-sequencing reanalyses confirm SUCNR1 as a therapeutic vulnerability in patients. Together, Sucnr1 signaling restricts hematopoiesis at least partially through HSPC and via control of S100a8/S100a9. Its dysregulation emerges as contributor to malignancy that opens therapeutic avenues for AML patients.

Mitochondria regulate cellular processes through direct and indirect interactions with other organelles. A well-studied example has been contact with the endoplasmic reticulum at mitochondrial-associated endoplasmic reticulum membranes1, which control pathways including redox and calcium homeostasis2,3. Recent studies have also reported direct mitochondria-nuclear membrane contacts in cancer cells and yeast that promote pro-survival signalling4,5. Here we identify direct interactions between mitochondria and nuclear pores. Using two unbiased proteomic screens, GST pulldown and BioID, we found that VDAC1 was the top mitochondrial candidate that interacts with the filamentous nuclear pore protein RANBP2. In vitro RANBP2 CRISPR knockout, RANBP2 truncation or site-directed mutagenesis of RANBP2-VDAC1 interacting amino acids resulted in reduced mitochondria-nucleus proximity and decreased nuclear ATP and phosphocreatine levels. This was accompanied by a decline in the levels of the nuclear phosphoproteome and downregulation of pathways involved in histone modification, cellular differentiation and transcriptional regulation in vitro. Moreover, deletion of the RANBP2 C-terminal domain in vivo in mice resulted in embryonic lethality due to cardiac and neural crest differentiation defects. Collectively, these results describe a mechanism by which mitochondria directly interact with the nuclear pore complex, a phenomenon critical for regulation of nuclear energetics and cellular differentiation. Undoubtedly, additional roles of this interaction remain to be revealed.

BACKGROUND:Global Vhl knockout results in vascular defects and early lethality, limiting our knowledge of VHL (von Hippel-Lindau)/HIF (hypoxia-inducible factor) signaling in coronary vessel formation and homeostasis. The hypoxia pathway has been implicated in cardiovascular diseases (CVDs) characterized by inflammation and vascular remodeling, such as atherosclerosis, but its involvement in Kawasaki disease (KD) remains unknown. Coronary artery dilation and vessel rupture are the most serious complications of KD. However, the molecular mechanisms underlying these cardiac events are not fully understood. We investigated the role of the VHL/HIF pathway in cardiovascular pathology and its relevance to KD. METHODS:We generated a novel mouse model with genetic hyperactivation of the hypoxia pathway in progenitors contributing to coronary vessels and cardiac fibroblasts. We characterized the model using echocardiography, magnetic resonance imaging, histology, and molecular profiling. In parallel, we examined cardiac tissues from patients with KD with fatal coronary aneurysms for evidence of HIF signaling and inflammation using immunohistochemistry. RESULTS:Mice with conditional deletion of Vhl in the Wt1 (Wilms tumor 1) lineage developed normally but exhibited cardiomegaly, vascular abnormalities, progressive coronary artery dilation, pericardial hemorrhage, and systemic inflammation shortly after birth. Histologic analysis revealed coronary arteritis, elastin breaks, vascular remodeling, smooth muscle cell loss, perivascular fibrosis, and frequent intracoronary thrombus formation. In addition, vascular calcification, severe cardiac inflammation, and interstitial hemorrhages were observed, culminating in sudden death between 15 and 20 weeks of age, likely due to vessel rupture. Cardiac transcriptomic profiling identified dysregulated expression of genes involved in extracellular matrix organization, epithelial-mesenchymal transition, angiogenesis, inflammation, coagulation, and calcification, indicating compromised vascular stability and increased remodeling in Vhl conditional knockout mice. Simultaneous deletion of Hif2a rescued both the cardiovascular abnormalities and transcriptomic profile observed in Vhl conditional knockout mice, implicating Hif2 (hypoxia-inducible factor 2) as a key mediator. Human KD cardiac samples showed expression of HIF2 in coronary lesions and surrounding inflammatory infiltrates, confirming hypoxia pathway activation in severe KD. CONCLUSIONS:Our findings establish HIF2 as a central driver of coronary inflammation, vascular remodeling, and thrombotic complications resembling those observed in severe KD. The Vhl/Wt1 conditional knockout mouse model recapitulates key cardiovascular features of KD and offers a valuable platform for mechanistic studies and therapeutic exploration.

Background Atherosclerosis may start early in life, progressing silently for decades before clinical presentation of atherosclerotic cardiovascular disease (ASCVD) occur. Current preventive strategies rely on only five risk factors (age, sex, cholesterol levels, blood pressure, and smoking), and the available risk scores do not include young adults (< 40 years old). Importantly, the risk scores do not account for the presence of the actual disease, atherosclerosis, resulting in lower precision at the individual level. The aims of Phase 1 of the REACT initiative are to determine the prevalence of silent atherosclerosis across the lifespan and to identify its sex- and age-specific predictors using both contemporary and more advanced methods such as multi-territory vascular imaging and multi-omics profiling. Methods This prospective cohort study is enrolling 16,000 representative adults (18–70 years, women-to-men ratio 1:1) from Denmark and Spain, without a history of ASCVD. The presence and burden of silent atherosclerosis is assessed by 3D vascular ultrasound of the carotid and femoral arteries, and by computed tomography angiography of the coronary, carotid, and femoral arteries. Microvascular status is assessed by retina imaging. Risk factor assessment for silent atherosclerosis includes traditional factors supplemented with detailed questionnaires, physical examinations, blood and urine analyses, as well as multi-omics profiling. Conclusion By providing a detailed understanding of the predictors and age- and sex stratified prevalence of silent atherosclerosis across multiple vascular territories, phase 1 of the REACT project will inform and advance future personalized ASCVD prevention strategies.

BACKGROUND:Nonmyocytes may contribute to regional adaptive changes during persistent atrial fibrillation (PsAF), favoring its perpetuation. We aimed to investigate the differential features of fibroblast and macrophage populations within individual-specific atrial regions associated with PsAF maintenance. METHODS:The study was conducted in 2 pig models of PsAF with and without infarct-related substrate (N=27 and N=27, respectively) and further validated in humans with PsAF (N=20). Sham-operated pigs (N=9), healthy animals (N=4), and patients in sinus rhythm (N=7) were used as comparative controls. In pigs, in vivo high-density instantaneous frequency modulation maps were used to identify atrial regions associated with PsAF maintenance (drivers). Regional cellular composition and phenotypic states of fibroblast and myeloid lineages were determined using flow cytometry, single-cell RNA sequencing, immunohistochemistry, and proteomic analyses. The functional relevance of driver regions was further studied in patients with symptomatic PsAF undergoing ablation. Flow cytometry and single-cell RNA sequencing analyses were performed in tissue samples of the left atrial appendage in a complementary cohort of patients with PsAF undergoing thoracoscopic-guided ablation. RESULTS:PsAF terminated acutely in 12 of 14 pigs undergoing mapping and ablation of driver regions. In humans, driver ablation was associated with 90% AF-freedom (on/off antiarrhythmic drugs) after 2 years of follow-up. Samples from nonablated pigs revealed a phenotypic shift towards ACTA2 (actin alpha 2)-fibroblasts and PTX3 (pentraxin 3)-fibroblasts during PsAF. Although ACTA2-fibroblasts were highly preserved in human samples, paired comparisons in pig samples showed that PTX3-fibroblasts were enriched only in driver regions. PsAF also showed changes in myeloid cells towards inflammatory profiles. However, regional analysis revealed that, in both humans and pigs with PsAF, driver regions were enriched in cardiac resident macrophages with transcriptomic and proteomic profiles favoring cardiomyocyte homeostasis and cell survival. CONCLUSIONS:PsAF shows differential regional changes in fibroblast and myeloid populations with distinctive gene signatures in areas that drive the overall arrhythmia.

Elite controllers (ECs) represent a unique subset of people living with HIV (PLWHs), who can suppress viral replication without requiring antiretroviral therapy (ART). However, despite this viral control, ECs exhibit increased incidences of various comorbid conditions and heightened systemic inflammation, which has been linked to monocyte activation. In this study, we performed an in-depth phenotypic analysis of monocytes in a cohort of long-term ECs (LTECs) and compared them to non-controller patients with ART-mediated control of HIV replication and to non-controller patients with uncontrolled viral replication. A total of 67 participants were included: 22 LTECs, 15 non-controllers on ART (onART), 10 non-controllers without ART (offART), and 20 uninfected controls (UCs) as a reference group. Monocyte phenotypes were analyzed using spectral flow cytometry with a 13-marker panel. The data were analyzed using two approaches: (a) FCS Express software v.7 to define different subsets of monocytes and assess the levels of expression of eight different monocyte functional markers and (b) R software v.4.1.1 for unsupervised multidimensional analysis, including batch correction, dimensionality reduction, and clustering analysis. Monocyte phenotypic profiling was conducted using three different approaches: (1) assessment of monocyte subsets (classical, intermediate, and non-classical monocytes); (2) evaluation of the levels of expression of eight monocyte functional markers, and (3) characterization of monocyte clusters defined through the dimensionality reduction of flow cytometry data (56 different clusters). The monocyte phenotype of the onART group closely resembled that of the UC group. In contrast, LTECs exhibited important alterations in the monocyte phenotype compared to that of the UCs, including (a) an increased proportion of intermediate monocytes and a decreased proportion of classical monocytes (p < 0.01), (b) altered expressions of functional markers across monocyte subsets (p < 0.05), and (c) alterations in sixteen different monocyte clusters (twelve decreased and four increased, p < 0.05). Many of these alterations were also observed when comparing the LTEC and onART groups. Our findings suggest that monocyte-driven mechanisms may contribute to HIV control in LTECs; however, some of these alterations could also promote systemic inflammation and immune activation. These observations provide a compelling rationale for considering therapeutic interventions in this unique population of PLWHs.

Positron emission tomography (PET) imaging with the radiolabeled glucose analog fluorodeoxyglucose ( 18 FDG) is used to monitor atherosclerosis in clinical trials, but there is uncertainty regarding the plaque cell types that accumulate FDG and how uptake is regulated. The long-standing view that 18 FDG is mainly taken up by macrophages is at odds with human and experimental data, and the impact of disease activity on 18 FDG uptake has not been examined directly. To analyze the ability of 18 FDG-PET to monitor disease activity, we developed a model of plaque regression in minipigs with hepatic overexpression of a gain-of-function mutant of proprotein convertase subtilisin/kexin type 9 ( PCSK9 ). Atherosclerosis was induced through 12 months of high-fat feeding in the porcine model. Disease activity was then lowered for 3 months by reducing plasma cholesterol with a low-fat diet alone or in combination with the microsomal transfer protein (MTP) inhibitor BMS-212122. Plaque regression in advanced lesions of the abdominal aorta was evident from reduced lipid content, reduced necrotic core size, and partial resolution of plaque inflammation and was accompanied by a decline in 18 FDG-PET signal. Single-cell gene expression profiling revealed that plaque regression involved substantial down-regulation of genes encoding glycolytic enzymes in smooth muscle cells (SMCs), macrophages, and lymphocytes, which was corroborated by analysis of the plaque cellular proteome. These findings in a large-animal model suggest that 18 FDG-PET can monitor atherosclerosis because of a close association between disease activity and glycolytic enzyme expression in all of the major plaque cell types.

CAV1 is a protein-coding gene linked to several disorders, including cancer, lipodystrophy, and cardiovascular diseases. While its ability to respond to various mechanical and metabolic stimuli has been documented, a comprehensive understanding of its physiological regulation in humans is lacking. We leveraged the comprehensiveness of human post-mortem tissue data from the Genotype-Tissue Expression (GTEx) consortium, systematically exploring the sources of variability in CAV1 transcriptional levels using extensive bulk and single-nuclei RNA-seq datasets. This human-centric approach, avoiding inter-species comparisons, constitutes a unique resource to explore CAV1 regulation within the complexity of human tissues. Notably, cell type proportion was identified as a major determinant of CAV1 transcription levels across tissues. Donor physiological conditions, including disease states and end-of-life circumstances, also exhibited a tissue-specific influence. Among primary upstream regulators associated with CAV1, chromatin modifiers stood out, especially SMARCA2, which showed a positive correlation across tissues, and PRC2 complexes, which exhibited tissue-specific correlation. Upstream regulatory networks determining CAV1 levels are also enriched for annotations such as mechanobiology (e.g., TEAD4), immunity (e.g., RELA and STAT3), and metabolism (e.g., MYC and NRF1). A remarkable observation was a strong correlation between CAV1 and the relative infiltration of immune cells across tissues, supporting a potential role for CAV1 as a marker and driver of tissue immune infiltration.

The salamander limb has served as a canonical model for successful regeneration that has yielded numerous molecular insights on its basic mechanism. Harnessing such information to induce regeneration in a non-regenerative setting has been a long-sought goal. The amputated salamander limb efficiently regenerates all of its missing bones, but paradoxically, a large bone gap without amputation – commonly called a Critical Size Defect (CSD) – is not regenerated, similarly to other vertebrates 1 . This non-regenerating injury provides a human-relevant setting to understand how to rescue lack-of-regeneration. Satoh and colleagues demonstrated in axolotl that transplantation of blastema cells from an amputated limb into a CSD yields cartilage bridging of the CSD 2 . This work provided a roadmap for rescuing the CSD. Here we asked, what are the crucial molecular differences in cells populating a regenerating blastema versus the CSD and can they be used to elicit CSD bridging? Previous genetic fate mapping and single cell transcriptomics showed that limb regeneration occurs via migration and dedifferentiation of fibroblastic, soft connective tissue (CT) cells that form a multipotent, skeletal stem cell 3, 4 . Here using single cell transcriptomics and genetic fate mapping we found that the CSD is populated by CT cells that undergo a divergent molecular transition compared to the blastema. Using gene regulatory network (GRN) modeling, and lipid nanoparticle (LNP) delivery of mRNA we could express a single molecular factor, Wnt3a , to induce cartilage bridging of the CSD. Our results demonstrate the power of using molecular information from successful regeneration to rescue a non-regenerating injury.

BACKGROUND:Stroke remains a leading cause of mortality and disability, driven by complex, time-dependent mechanisms that aggravate ischemic injury. Collateral perfusion dictates infarct size, expansion rate, and penumbral preservation, yet its regulation is poorly understood. Beyond structural/genetic factors such as aging or cardiovascular risk, functional influences like circadian immune activity may also affect vascular patency. Neutrophils, key mediators of ischemic injury, exhibit circadian oscillations in phenotype and function that could modulate collateral flow and stroke outcome. METHODS:We combined permanent and transient middle cerebral artery occlusion models in mice with flow cytometry, single-cell RNA sequencing, confocal microscopy, and laser speckle imaging to investigate time-of-day-dependent neutrophil mechanisms in stroke. Pharmacological (chloramidine, DNase-I) and genetic (Pad4 [peptidyl arginine deiminase 4]-/-, Bmal1 [brain and muscle ARNT (aryl hydrocarbon receptor nuclear translocator)-like 1]Neu, Cxcr4 [C-X-C chemokine receptor type 4]Neu) interventions were used to define how time-of-day regulation shapes neutrophil function, neutrophil extracellular traps (NETs) formation, and stroke severity. A cohort of 540 patients with ischemic stroke was analyzed for diurnal patterns of NET-related biomarkers and their association with collateral circulation and clinical outcomes. RESULTS:Infarct volume and neurological deficits exhibited clear circadian oscillations, with worse outcomes when stroke occurred during the murine inactive phase (Zeitgeber time 5) versus the active phase (Zeitgeber time 13). These fluctuations disappeared after neutrophil depletion or clock disruption. During the inactive phase, neutrophils displayed an activated, NET-prone phenotype, causing microvascular stalling and reduced collateral perfusion. Inhibiting NET formation pharmacologically or through Pad4 deletion restored perfusion and abolished time-of-day effects. In patients, neutrophil and NET-related biomarkers (MPO [myeloperoxidase], elastase, sCD40L [soluble CD40 ligand]) showed diurnal oscillations, peaking during the human inactive phase (evening/night), coinciding with reduced collateral flow and poorer outcomes. CONCLUSIONS:Time-of-day regulation of neutrophil function critically determines collateral perfusion and stroke severity. Neutrophil-driven NETosis during the inactive phase promotes microvascular obstruction and worsens outcomes. Targeting NET formation or timing therapy could enhance collateral efficacy and offer novel chronotherapeutic opportunities for stroke treatment.

Acute myocardial infarction remains a leading cause of morbidity and mortality worldwide. Pharmacogenetic and chronotherapeutic approaches are increasingly applied to optimize therapy in chronic cardiovascular diseases. While gene variants are known to influence long-term drug efficacy, their role in modulating drug-induced cardioprotection in acute conditions such as myocardial infarction is unclear. Similarly, the impact of circadian timing on cardioprotective responses remains insufficiently defined. To address these questions, we evaluated metoprolol as a model cardioprotective agent. Here we examine, in a non-pre-specified exploratory analysis of the METOCARD-CNIC trial (NCT01311700), the influence of ADRB1 Arg389Gly polymorphism and the time of AMI onset on metoprolol efficacy. We found that metoprolol reduced infarct size only in patients homozygous for the ADRB1 Arg389 allele, consistent with its genotype-dependent inhibition of neutrophil migration. In-silico docking and binding studies revealed unstable interactions of metoprolol with the Gly389 variant of ADRB1. Moreover, metoprolol was associated with reduced infarct size when AMI onset occurred between 6:00 and 12:00 h. Restricted cardioprotection to the light phase was confirmed in male mice and in neutrophil-specific Adrb1-knockout models. Collectively, these findings highlight the critical roles of genetic background and circadian timing in shaping the efficacy of acute cardioprotective therapies, supporting the rationale for personalized interventions in acute myocardial infarction.

Impairment of the intestinal barrier allows the systemic translocation of commensal bacteria, inducing a proinflammatory state in the host. Here, we investigated innate immune responses following increased gut permeability upon administration of dextran sulfate sodium (DSS) in mice. We found that Enterococcus faecalis translocated to the bone marrow following DSS treatment and induced trained immunity (TI) hallmarks in bone-marrow-derived mouse macrophages and human monocytes. DSS treatment or heat-killed E. faecalis reprogrammed bone marrow progenitors (BMPs), resulting in enhanced inflammatory responses in vitro and in vivo and protection against subsequent pathogen infections. The C-type lectin receptor Mincle (Clec4e) was essential for E. faecalis-induced TI in BMPs. Clec4e-/- mice showed impaired TI upon E. faecalis administration and reduced pathology following DSS treatment. Thus, Mincle sensing of E. faecalis induces TI that may have long-term effects on pathologies associated with increased gut permeability.

Stroke is a leading cause of mortality and disability, driven by complex and time-dependent mechanisms that aggravate ischemic damage. Recent evidence indicates that infarct volumes fluctuate according to diurnal oscillations, both in mice and humans, with worse outcomes during the inactive phase of their circadian cycle. Here, we show that neutrophils are responsible for these circadian variations. By depleting neutrophils or blocking their circadian clock, differences in infarct volumes were abolished, suggesting that both the number of neutrophils and their circadian phenotype contribute to ischemic damage. Mechanistically, these differences were linked to the collateral circulation: cerebral blood flow measurements at different times after ischemia showed differential perfusion in the ipsilesional area. We found that, during the inactive mouse phase, neutrophil extracellular traps (NETs), were markedly elevated, coinciding with a reduction in ipsilesional blood flow, a higher percentage of intravascular neutrophils, and an increase in infarct volumes compared with the active phase. These findings underscore a crucial role of neutrophils, their circadian dynamics, and NET release as key drivers of ischemic damage, suggesting novel personalized therapeutic strategies based on circadian rhythms for the treatment of stroke. ### Competing Interest Statement The authors have declared no competing interest.