Nature Cardiovascular Research

Background: Non-monogenic arteriopathies are often classified as distinct entities according to the arterial territory involved, yet they share clinical features and may co-occur in the same individual. This pattern suggests shared susceptibility across anatomically distinct arteriopathies, potentially driven by common biological and genetic mechanisms. Methods: We investigated the shared genetic architecture of five arteriopathies (cervical artery dissection (CeAD), intracranial aneurysm (IA), spontaneous coronary artery dissection (SCAD), aortic aneurysm and dissection (AAD), and fibromuscular dysplasia (FMD)) using LD score regression, Association analysis based on SubSETs (ASSET), pairwise Multi-Trait Analysis of Genome-wide association summary statistics (MTAG), pleiotropy mapping and Mendelian randomization (MR) to identify shared loci and prioritise candidate causal genes. Results: LD score regression identified significant positive genetic correlations between CeAD-SCAD (rg = 0.64), IA-AAD (rg = 0.33), IA-SCAD (rg = 0.37), CeAD-AAD (rg = 0.56) and SCAD-AAD (rg = 0.20). ASSET identified 37 shared independent loci, and in MTAG analyses, one novel locus was identified for CeAD and SCAD (SLC39A8) and one for IA (FGF5). 13 loci showed strong cross-trait colocalization, including PHACTR1, LRP1, and CDKN2B-AS1. Using the Genotype-Phenotype Map, we found that arteriopathy-associated variants colocalized with blood pressure- and migraine-related traits, while many showed effect directions opposite to those observed for coronary artery disease. Proteome-wide MR identified 67 circulating proteins associated with at least one trait, including ECM1 and SHISA5 for CeAD and FGF5 for IA, with 17 supported by colocalization. Transcriptome-wide MR identified 204 colocalized tissue?specific signals, of which, 14 were shared across multiple traits. Enrichment analyses implicated pathways related to vascular development, smooth muscle cell function, extracellular matrix organization, and TGF-? signaling. Conclusions: These findings support shared genetic architecture across anatomically distinct arteriopathies, implicating pathways involved in vascular structure and prioritising therapeutic targets for future mechanistic investigation.

Activation of the immune system impacts the progression of heart failure (HF), but the underlying mechanisms remain incompletely understood. Here, we identify a cardio-intestinal innate immune axis that links systemic venous congestion to myocardial inflammation, fibrosis, and functional decline. Using single-cell and single-nucleus transcriptomic profiling in patients and mice with tricuspid regurgitation (TR), we demonstrate that TR disrupts intestinal barrier integrity and elicits expansion of circulating monocytes which in turn orchestrate pathological crosstalk between the right and left heart. Monocyte-derived Interleukin-6 (IL-6) emerged as a key mediator of TR-driven myocardial fibrosis and dysfunction. Blockade of IL-6 attenuated cardiac fibrosis and improved cardiac function. In patients, catheter-based repair of TR resulted in reduced IL-6 levels. Together, these findings establish cardio-intestinal innate immunity as a mechanism linking altered hemodynamics to left ventricular remodeling and nominate TR patients as a selective target population for IL-6-directed therapy in HF. One Sentence SummaryThis work mechanistically resolves the heart-gut axis in tricuspid valve regurgitation, and its impact on heart failure progression as mediated by Interleukin-6.

BackgroundCalcific aortic valve stenosis (AS) is the most common valvular heart disease in the aging population and lacks effective pharmacological therapy. Oxidative stress is a key feature of valvular remodeling, yet the mechanisms linking oxidative injury to calcification remain unclear. Ferroptosis, a lipid peroxidation-driven form of regulated cell death, has emerged as a key mediator of oxidative tissue injury and may contribute to cardiovascular disease. Vitamin K was recently identified as a suppressor of ferroptosis and cardiovascular calcification, but whether ferroptosis links vitamin K status to disease progression in AS remains unknown. Methods and ResultsWe investigated the role of lipid peroxidation and ferroptosis in AS and their modulation by vitamin K2 using a translational approach. In human stenotic aortic valves, lipid peroxidation was markedly increased and localized to calcified regions, consistent with a ferroptosis-associated microenvironment. In primary human valvular interstitial cells (VICs), pro-calcific conditions induced lipid peroxidation and a pro-ferroptotic state. Pharmacological induction of ferroptosis enhanced VIC calcification, whereas its inhibition attenuated mineralization, supporting a causal role in osteogenic remodeling. Impaired vitamin K status was associated with increased valvular lipid peroxidation in AS patients. Conversely, vitamin K2 attenuated lipid peroxidation, preserved cell viability under ferroptotic stress, and partially normalized pro-ferroptotic and inflammatory transcriptional programs in VICs. In a murine model of AS, dietary vitamin K2 supplementation attenuated disease progression, reduced transvalvular gradients, and decreased valvular inflammation and lipid peroxidation-associated pathways. Finally, in a prospective cohort of patients with aortic sclerosis to moderate AS (n = 157), circulating undercarboxylated osteocalcin, a marker of impaired vitamin K status, was independently associated with accelerated disease progression. ConclusionsVitamin K2 counteracts ferroptosis-associated lipid peroxidation in AS and attenuates disease severity in vivo. Impaired vitamin K status is independently associated with accelerated progression in patients. These findings position vitamin K2 as a potential disease-modifying strategy and vitamin K status as a prognostic marker in AS. What Is New?O_LIFerroptotic lipid peroxidation is enriched in calcified regions of human stenotic aortic valves. Pharmacological induction of ferroptosis increases, and its inhibition reduces, calcification of human valvular interstitial cells, indicating a causal contribution to valvular mineralization. C_LIO_LIVitamin K2 suppresses ferroptotic lipid peroxidation, preserves cell viability under ferroptotic stress, and shifts pro-oxidative and pro-inflammatory transcriptional programs in human valvular interstitial cells toward a protective state. C_LIO_LIIn an in vivo model of aortic stenosis, dietary vitamin K2 attenuated hemodynamic progression, with lower peak transvalvular velocity and mean gradient, and reduced valvular inflammation and lipid peroxidation, without affecting coagulation C_LIO_LIIn a prospective cohort of 157 patients with aortic sclerosis to moderate stenosis, impaired vitamin K status, reflected by higher circulating undercarboxylated osteocalcin, was independently associated with accelerated disease progression and with higher rates of mortality. C_LI What Are the Clinical Implications?O_LIAortic stenosis currently has no medical therapy. Vitamin K2, an inexpensive, safe nutrient that does not interfere with anticoagulation, emerges as a candidate disease-modifying strategy that warrants testing in randomized trials. C_LIO_LICirculating undercarboxylated osteocalcin may serve as a biomarker to identify patients at risk of rapid progression and to enrich future vitamin K trials for those most likely to benefit. C_LIO_LITargeting valvular lipid peroxidation, through antioxidant repletion and/or inhibition of lipid-peroxidation enzymes, may be a mechanistically grounded approach to slow calcific aortic valve disease. C_LI

Three-dimensional genome organization stabilizes cell-type-specific gene expression, yet the tissue-restricted factors that maintain chromatin insulation remain poorly understood. Here, we identify the muscle-specific ribosomal protein Rpl3l as an unexpected nuclear regulator of genome architecture in atrial cardiomyocytes. Rpl3l is enriched in the nucleus and nucleolus, where it binds its own genomic locus and stabilizes a CTCF-anchored chromatin boundary that represses the T-type calcium channel gene Cacna1h. Loss of Rpl3l weakens local chromatin insulation, increases long-range contacts across the Rpl3l-Cacna1h locus, derepresses Cacna1h, and increases susceptibility to atrial fibrillation (AF), which is suppressed by pharmacological inhibition of T-type calcium channels. Furthermore, AF-associated RPL3L variants exhibit impaired nucleolar localization, reduced rRNA binding, and defective repression of CACNA1H in human iPSC-derived atrial cardiomyocytes. Together, these findings reveal a ribosomal protein-chromatin axis linking genome insulation to ion-channel dosage control and cardiac rhythm stability, expanding the repertoire of cell-type-specific genome architecture regulators.

Vascular smooth muscle cell (SMC) growth, whether hyperplastic or hypertrophic, is a central determinant of vascular remodeling in cardiovascular disease, yet the molecular regulators that direct SMC toward a specific growth fate remain poorly understood. Here, we identify the long non-coding RNA CASC15 as a critical regulator of SMC growth and vascular remodeling. CASC15 is enriched in the vasculature and SMC-rich tissues in humans and mice, and its locus harbors SNPs significantly associated with coronary artery disease and blood pressure. We identify a novel SMC-selective CASC15 isoform (S-CASC15) whose expression level determines SMC growth fate: elevated S-CASC15 promotes proliferation, while its loss drives hypertrophy, polyploidization, and binucleation. In vivo depletion of CASC15 limits vascular injury-induced neointima formation and atherosclerotic lesion expansion. Conversely, CASC15 overexpression exacerbates injury-induced neointimal hyperplasia. However, CASC15 KO mice exhibit spontaneous medial hypertrophy and vascular hypercontractility. Mechanistically, loss of S-CASC15 expression causes mitotic defects, followed by arrest in the G1 phase of hypertrophic and polyploid cells. We found that S-CASC15 pro-proliferative function is mediated through its interaction with RNA-binding proteins, including Nucleolin, and by regulating the stability of cell cycle checkpoint gene transcripts, thereby ensuring mitotic fidelity. Together, these findings establish CASC15 as a pivotal molecular switch governing the balance between hyperplastic and hypertrophic vascular remodeling and as a potential therapeutic target in cardiovascular disease.

Mitochondrial DNA (mtDNA) released into the cytosol activates innate immune signaling and promotes inflammation, yet its role in macrophages following sterile tissue injury remains poorly understood. Here, we show that cardiac macrophages from both patients and mice with myocardial infarction (MI) exhibit increased mitochondrial biogenesis, mitochondrial content, membrane potential, and expression of mitochondrial nucleases that facilitate mtDNA release. Consistently, macrophage-specific silencing of genes regulating mitochondrial biogenesis or mtDNA processing attenuated adverse cardiac remodeling after MI. Unexpectedly, despite the role of mtDNA in activating the cGAS-STING pathway, myeloid deletion or macrophage-specific silencing of Sting or cGas exacerbated ventricular dilation, fibrosis, and contractile dysfunction following MI. Single-cell transcriptomic and cell communication analyses identified amyloid precursor protein (APP) as a key downstream effector of STING in cardiac macrophages. Macrophage-specific in vivo App silencing rescued the detrimental effects of myeloid Sting deficiency, establishing APP as a critical mediator of adverse remodeling. Mechanistically, STING interacted with the transcriptional repressor MZF1, promoted its nuclear localization, facilitated its binding to the App promoter, and suppressed App transcription to restrain adverse cardiac remodeling. Together, our findings uncover an unexpected cardioprotective function of myeloid STING and identify the STING-MZF1-APP axis as a previously unrecognized mechanism governing cardiac repair after myocardial infarction.

BackgroundHeart failure with preserved ejection fraction (HFpEF) is a systemic inflammatory syndrome with few effective therapies. Soluble urokinase plasminogen activator receptor (suPAR), a circulating immune-derived glycoprotein, independently predicts adverse outcomes in HFpEF beyond natriuretic peptides, but whether it is a causal driver or a passive marker of inflammatory burden has remained unresolved. MethodsWe tested the hypothesis that elevated circulating suPAR is sufficient to amplify HFpEF by acting on the innate immune system. suPAR-transgenic (suPAR-Tg) and wild-type mice were subjected to a cardiometabolic two-hit model (high-fat diet plus L-NAME) for 15 weeks. Cardiac structure and diastolic function were assessed by serial echocardiography alongside blood pressure, glucose tolerance, and gravimetric endpoints, and left ventricular tissue was profiled by bulk RNA sequencing with in silico cellular deconvolution. Myeloid populations in the heart, spleen, and peripheral blood were quantified by spectral flow cytometry and corroborated by galectin-3 immunofluorescence, and the direct effect of suPAR on macrophages was tested by priming bone marrow-derived macrophages with recombinant suPAR before LPS and IFN-{gamma} stimulation. ResultsSustained suPAR elevation worsened the established HFpEF phenotype, producing greater diastolic dysfunction (higher E/e' and E/A ratios) and pulmonary congestion without altering blood pressure or ejection fraction, indicating a mechanism downstream of the canonical hemodynamic stimulus. Bulk RNA sequencing of left ventricular tissue revealed a coordinated transcriptional shift, with suppression of mitochondrial oxidative phosphorylation and amplification of innate and adaptive immune programs, including interleukin-1{beta} production, leukocyte chemotaxis, and antigen presentation. Spectral flow cytometry demonstrated stepwise expansion of CCR2 inflammatory monocytes and macrophages across cardiac, splenic, and peripheral compartments, corroborated in situ by increased galectin-3 macrophage density. In vitro, recombinant suPAR was not a stand-alone inflammatory ligand but instead primed bone marrow-derived macrophages to markedly amplify TNF-, IL-1{beta}, IL-6, and NLRP3 responses to LPS and IFN-{gamma}. ConclusionsTogether, these findings establish that elevated suPAR is sufficient to act as an upstream amplifier of HFpEF, identify the CCR2 inflammatory monocyte-macrophage axis as its proximate effector, and convert two decades of epidemiologic association into a mechanistically grounded, therapeutically tractable hypothesis with immediate relevance to clinical-stage anti-suPAR antibodies.

Aims: Fatty liver disease has been associated with atrial fibrillation (AF), yet the liver-heart axis, the interplay between hepatic fibro-inflammation, systemic metabolism, and genetic susceptibility, remains poorly defined. We aimed to characterize this axis and its association with incident AF. Methods and Results: In this prospective cohort study, liver fibrosis was assessed via four biochemical indices and magnetic resonance imaging (corrected T1 [cT1]). We integrated metabolome-wide causal mediation (249 nuclear magnetic resonance [NMR] features) with Elastic Net modelling, cardiac phenomapping (cardiac magnetic resonance and electrocardiogram), and unsupervised clustering. A metabolomic risk score (MRS) was derived and evaluated for gene-environment interactions with an AF polygenic risk score (PRS) and for incremental prediction beyond CHARGE-AF, ARIC, and C2HEST. Among 403,974 UK Biobank participants (median follow-up 13.18 years), 26,677 developed incident AF. High-risk NAFLD fibrosis score (NFS; HR 1.54, 95% CI 1.43-1.66), Fibrosis-4 index (FIB-4; HR 1.53, 95% CI 1.44-1.62), and liver MRI cT1 (HR 1.41, 95% CI 1.11-1.79) were independently associated with AF. Phenomapping identified a dual-track axis: (1) systemic inflammation and lipotoxicity linked to electrophysiological alterations without chamber dilation, and (2) fatty-acid imbalance associated with structural enlargement. Three metabolomic clusters emerged; a "Fibro-Inflammatory" phenotype exhibited distinct metabolomic derangements, ketogenic stress, and a high residual AF risk independent of traditional comorbidities. The MRS compounded AF risk across all PRS strata and improved prediction beyond CHARGE-AF ({Delta}AUC +0.005; cNRI 10.2%), ARIC ({Delta}AUC +0.006; cNRI 11.7%), and C2HEST ({Delta}AUC +0.042; cNRI 32.2%). Conclusions: Liver fibrosis is a robust predictor of AF. A fibro-inflammatory hepatic-metabolomic signature defines a modifiable axis that potentiates genetic susceptibility and enhances AF risk stratification. Targeting liver-derived metabolic dysfunction may offer a new therapeutic avenue for AF prevention.

Myocardial infarction is a leading cause of death and disability worldwide. Ischemic injury leads to irreversible loss of cardiomyocytes, the contractile cells of the heart, and formation of a fibrotic scar. After infarction, macrophages massively infiltrate the heart and orchestrate the tissue repair process by removing dead cells and modulating fibroblast activation for scar formation. We previously demonstrated that diverse monocyte-derived macrophage populations dynamically accumulate in the heart following myocardial infarction, notably a pro-repair Trem2hi subset. In this study, we leveraged spatial transcriptomics, single-cell RNA-seq, and functional assays to elucidate the role of TREM2 in driving macrophage-mediated cardiac tissue repair post-infarction. We show that Trem2hi macrophages localize in scarring areas of the infarcted myocardium in the vicinity of collagen-producing myofibroblasts. In Trem2-/- mice, cardiac accumulation of monocyte-derived macrophages with a pro-scarring matrisome-associated macrophage signature was reduced. TREM2 deficiency was functionally associated with reduced fibroblast proliferation, accumulation of myofibroblasts, decreased collagen deposition in the infarcted heart, and increased infarct size. In vitro, we show that TREM2 mediates efferocytosis-induced pro-fibrotic gene expression and promotes macrophage ability to induce fibroblast migration. IL-4 priming of bone marrow-derived macrophages further increased the pro-fibrotic response in macrophages, suggesting that IL-4 and efferocytosis act synergistically to drive this phenotype. Altogether, our results show that TREM2 is essential for the accumulation and function of pro-scarring monocyte-derived macrophages in the infarcted myocardium.

Cellular senescence is a hallmark of aging and an emerging therapeutic target; however, its role as a context-specific driver of disease remains incompletely defined, and senolytic therapies have shown inconsistent clinical benefit. Here, we identify extracellular matrix (ECM)-dominant pathologies as a major class of senescence-driven disease, characterized by inflammation, matrix degeneration, and progressive tissue dysfunction. Using integrated single-cell transcriptomics, spatial profiling, and multiplex imaging across human specimens and murine models, we demonstrate that senescent fibroblasts, rather than canonical myofibroblasts, constitute the principal disease-driving cell state in myxomatous mitral valve disease (MMVD) and related conditions. These cells exhibit coordinated CDKN1A inflammatory and CDKN2A ECM-remodeling programs that form a feed-forward circuit linking immune activation to matrix disorganization and functional decline. Senescence extends beyond fibroblasts to endothelial and immune compartments, establishing a multicellular senescent milieu that reinforces intercellular crosstalk and disease progression. Senolytic treatment (dasatinib plus quercetin or fisetin) restores ECM architecture and improves cardiac function, outperforming pathway-specific anti-inflammatory and antifibrotic approaches. Cross-disease analyses further reveal conservation of this coordinated CDKN1A/CDKN2A senescence programs across multiple ECM-dominant cardiovascular diseases, including aortic aneurysm and calcific valve disease. Notably, in vivo single-cell transcriptomic profiling following multiple senolytic treatments provides whole-transcriptome resolution of context-dependent cellular responses. Collectively, these findings establish context-specific senescence as a central organizing mechanism in ECM-dominant diseases and support a shift from generalized anti-aging strategies toward precision senolytic prevention or therapy. Given that valvular and aortic diseases affect millions and increase markedly with age to a prevalence comparable to major cancers, these results indicate a potential solution to a substantial and underrecognized clinical burden.

Aortic stenosis (AS) is a heterogeneous disease of aging characterized by valvular calcification and distinct structural, electrical, and hemodynamic remodeling that are incompletely captured by any single diagnostic measure. Here we show that three AI-derived digital biomarkers resolve AS-related remodeling into complementary structural (cine-CMR Digital AS Severity Index, DASSi), electrical (AI-ECG), and hemodynamic (phase-contrast CMR peak aortic velocity) axes. Among 68,714 UK Biobank participants, all three biomarkers were independently associated with prevalent AS and prospectively predicted aortic valve replacement. Genetic and transcriptomic analyses of the digital phenotypes revealed partially distinct, heritable architectures: peak aortic velocity aligned closely with clinical AS genetics, whereas DASSi and AI-ECG defined a shared myocardial-remodeling axis largely independent of clinical AS susceptibility. These findings support AS as a multidimensional remodeling syndrome and establish a novel digital phenotyping framework for dissecting complex cardiovascular disease into complementary, biologically informative axes.

The cellular origin of smooth muscle cell (SMC)-derived populations in vascular lesions remains unresolved. Here we show, using single-cell transcriptomic analyses spanning carotid ligation injury, Myh11-CreERT{superscript 2}-traced aortic homeostasis, and LDLR- and ApoE-deficient atherosclerosis, that a rare progenitor-like "Primed" SMC compartment pre-exists at baseline in all models and in the healthy human aorta. Relative to contractile SMCs, Primed SMCs attenuate sarcomeric and contractile programmes while inducing matricellular, progenitor-niche and chondrogenic-poised developmental programmes, resolving into conserved niche/progenitor (Cd34, Fst, Tnfrsf11b) and matricellular (Vcam1, Thbs1, Timp1) cores overlaid by vessel-specific signatures, on a retained SMC identity. Multiple orthogonal computational lineage-inference approaches indicate that this compartment expands predominantly through autonomous self-renewal and is the dominant inferred source of cycling and lesion fibrochondrocyte populations, while contractile SMCs are consistently depleted as a feeder source. These findings reframe lesional SMC cellularity as expansion of a pre-existing Primed compartment rather than widespread phenotypic switching of contractile SMCs.

Sporadic ascending aortic dissection (AAD) carries high short-term mortality and long-term morbidity. Hypertension is the predominant risk factor, yet no established tools identify patients at imminent risk. Although medial vulnerability likely contributes to dissection in heritable aortopathies, AAD predominantly understood as a luminal breach followed by false-lumen propagation, with comparatively less emphasis on the underlying medial substrate. We sought to define the vascular smooth muscle cell (VSMC) landscape in human AAD and identify spatial remodeling programs associated with interlamellar separation. Using Xenium in situ spatial transcriptomic profiling, we generated cellular-resolution maps of the dissected human ascending aorta. We identified extensive VSMC remodeling organized into distinct laminar domains across the aortic media, with distinct VSMC states supported by gene-expression module scoring and trajectory analysis. A reproducible mid-medial core of chronically hypoxia-adapted VSMCs was identified across patients and supported by carbonic anhydrase 9 immunohistochemistry. These hypoxia-adapted VSMCs lacked inflammatory and immediate-early activation programs and were spatially distinct from stress-responsive VSMC states enriched along the false lumen. Circumferential profiling in a complete aortic ring demonstrated greater adaptive remodeling in the outer curve compared with the inner curve. In contrast, donor control aortas contained fewer modulated VSMC states, less laminar striation, and no comparable hypoxia-adapted core. These findings define a spatially organized medial remodeling landscape in AAD and identify hypoxia-associated VSMC modulation as a potential feature of medial domains associated with heightened vulnerability to interlamellar separation. Defining these remodeling domains may inform improved risk stratification and experimental models that better recapitulate human AAD pathology.

BACKGROUNDMyocardial fibrosis, a pathological hallmark of adverse cardiac remodeling and heart failure, has been conventionally attributed to the activation of resident fibroblasts. Although recent studies suggest contributions from non-fibroblast lineages, direct in vivo genetic evidence that cardiomyocytes can undergo a mesenchymal-like fate transition during myocardial fibrosis remains absent. This study aims to investigate whether such a transition occurs and to elucidate the underlying regulatory mechanisms. METHODSHuman myocardial infarction (MI) tissues were analyzed by immunohistochemistry and integrated with public single-nucleus RNA sequencing (snRNA-seq) data to detect mesenchymal-like signatures in cardiomyocytes. Genetic lineage-tracing was performed in MI mice, and in cardiomyocyte-specific Hgs (hepatocyte growth factor-regulated tyrosine kinase substrate) gene knockout mice, to map the fate of cardiomyocyte-derived cells. Mechanistic insights were obtained through proteomic and snRNA-seq analysis of Hgs knockout hearts and validated through gain- and loss-of-function experiments targeting Aldh1a2 (aldehyde dehydrogenase 1 family member A2). RESULTSIn human MI samples, a subset of cardiomyocytes showed reduced expression of cardiomyocyte markers concurrent with acquisition of mesenchymal-associated markers. Genetic lineage tracing demonstrated that adult cardiomyocytes can adopt a mesenchymal-like cell fate during post-MI remodeling. We identify HGS as a factor constraining this transition. Hgs knockout in adult cardiomyocytes upregulated Aldh1a2, triggered the mesenchymal-like fate transition, and gave rise to cells expressing markers of activated fibroblasts or osteoblasts, accompanied by pronounced myocardial fibrosis and calcification. Forced Aldh1a2 overexpression in cardiomyocytes drove the mesenchymal-like fate transition in vitro and in vivo, whereas Aldh1a2 deletion in cardiomyocytes mitigated MI-induced myocardial fibrosis. CONCLUSIONSThis study provides in vivo genetic evidence that adult cardiomyocytes possess the capacity to undergo a mesenchymal-like fate transition under pathological conditions. Our data suggest that HGS and ALDH1A2 serve as regulators of the transition, offering a new basis for understanding cellular and molecular mechanisms of myocardial fibrosis. Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIMyocardial fibrosis is primarily driven by resident fibroblast activation, with additional contributions from cardiac CD34+ cells, pericytes, and macrophages. C_LIO_LIAdult cardiomyocytes exhibit phenotypic plasticity and transdifferentiate into epicardial-like or pacemaker cells under specific conditions. C_LI What New Information Does This Article Contribute?O_LIA subset of cardiomyocytes adopts a mesenchymal-like cell fate during myocardial fibrosis, marked by downregulation of cardiomyocyte identity markers and loss of aligned cell-cell contacts. C_LIO_LIThese cells acquire mesenchymal morphology and markers, ECM components, migratory gene signatures, and proliferative capacity. C_LIO_LIHGS and ALDH1A2 act as regulators of this mesenchymal-like fate transition. C_LI Myocardial fibrosis drives heart failure progression, yet the cellular sources of pathological fibroblasts remain incompletely defined. Here, we demonstrate that a subset of cardiomyocytes adopts a mesenchymal-like cell fate during myocardial fibrosis by using an integrated approach combining human MI samples, murine genetic lineage tracing, and snRNA-seq. Mechanistically, we identify HGS and ALDH1A2 as regulators of this transition. Cardiomyocyte-specific Hgs deletion upregulates Aldh1a2, triggering the mesenchymal-like fate transition. Furthermore, Aldh1a2 overexpression drives this transition, while its deletion attenuates MI-induced fibrosis. These findings reveal a previously unrecognized plasticity of adult cardiomyocytes and identify potential therapeutic targets for fibrotic heart disease.

BackgroundAortic aneurysm and aortic dissection (AAD) are lethal cardiovascular emergencies characterized by sudden onset and extremely high early mortality. The pro-inflammatory polarization of macrophages is one of the core factors driving the pathogenesis of AAD, but its underlying mechanism remains unclear. This study focuses on the aberrant expression of glycogen synthase 2 (GYS2) in the AAD microenvironment and its role in driving macrophage polarization toward the pro-inflammatory M1 phenotype. MethodsProteomic analysis was conducted to identify protein heterogeneity associated with AAD. Clinical and animal samples were used to evaluate the correlation between GYS2 expression and AAD progression. Whole-body GYS2 knockout mice and adeno-associated virus (AAV)-mediated macrophage-specific gain- and loss-of-function models were utilized to investigate the regulatory role of GYS2 in macrophage polarization and complement activation. Downstream molecular pathways were identified and validated through in vitro stimulation and in vivo exogenous C5a rescue experiments. ResultsGYS2 expression was significantly upregulated in AAD tissues and primarily localized in macrophages. Activation of GYS2 by LiCl or macrophage-specific overexpression of GYS2 exacerbated aortic dilation and extracellular matrix degradation, and increased mortality in AAD mice. Conversely, whole-body GYS2 knockout or macrophage-specific GYS2 knockdown suppressed inflammatory factors, significantly reduced the incidence of AAD, and attenuated vascular injury. Mechanistically, excessive GYS2 in macrophages specifically triggered the complement-coagulation cascade, promoting the generation of the potent anaphylatoxin C5a. C5a further bound to its receptor C5AR1, activating the downstream PLC{beta}3/NF-{kappa}B signaling pathway, thereby inducing M1 macrophage polarization and matrix metalloproteinase-mediated extracellular matrix degradation. In vivo exogenous C5a rescue completely reversed the vascular protective effects conferred by GYS2 deficiency. ConclusionsThis study demonstrates that highly expressed GYS2 regulates the pro-inflammatory polarization of macrophages and extracellular matrix degradation via the complement C5a/PLC{beta}3/NF-{kappa}B signaling axis, which is a key mechanism driving AAD progression. Specific inhibition of macrophage GYS2 can effectively alleviate aortic vascular inflammation and prevent AAD progression, providing a promising novel strategy for the clinical conservative treatment of AAD.

Background: Pulmonary arterial hypertension (PAH) is driven by maladaptive endothelial remodeling, but the transcriptional regulators that couple proliferative stress to arterialized endothelial states remain incompletely defined. E2F transcription factor 1 (E2F1) is classically viewed as a cell-cycle regulator; whether E2F1 functions as a disease-driving node that promotes endothelial arterial programming in PAH remains unknown. Methods: We integrated human PAH lung transcriptomic analyses, deconvolution-based endothelial-state scoring, and complementary mouse and rat PH models with bulk RNA-seq, single-cell RNA-seq, pseudotime analysis, and CellChat inference. E2F1 function was tested using adenoviral E2F1 overexpression, pharmacological pan-E2F inhibition with HLM006474, and E2f1 loss on a tamoxifen-inducible endothelial Egln1-deletion background. Results: In IPAH lungs, E2F1 was increased and arterial endothelial cell (AEC) fraction and expanded arterial program scores were elevated. Similarly, Egln1Tie2Cre lungs showed increased E2F1, induction of arterial remodeling genes, and activation of an E2F target program. Genetic loss of E2f1 reduced RVSP, RV hypertrophy, vascular remodeling, and distal muscularization in Egln1-driven PH mice model. Bulk RNA-seq showed suppression of E2F/G2M, mitotic, EMT, and ECM-remodeling programs. Single-cell RNA-seq showed reduced AEC accumulation, normalized CAP1/CAP2 distribution, and reduced progression along the CAP1-iAEC-AEC trajectory. CellChat analysis identified loss of an arterial communication hub, including reduced ECM, VEGF, and Notch signaling when E2F1 is loss. Conversely, E2F1 overexpression in HLMVECs increased proliferation, activated E2F/cell-cycle and Notch/arterial programs. Pharmacological inhibition of E2F via HLM006474 suppressed VEGF-A- and hypoxia-induced endothelial proliferation and attenuated Egln1-driven and MCT-induced PH, including reversal of established MCT-PH. Conclusions: E2F1 acts as a disease-relevant transcriptional factor linking endothelial cell-cycle activation to arterial programming, matrix and angiogenic communication programs, and pulmonary vascular remodeling. Genetic or pharmacological E2F inhibition mitigates experimental PH, supporting E2F1 as a therapeutic target in PAH.

Human cardiac injury responses are governed by dynamic interacting processes that are difficult to resolve. Unlike adults, fetal mammalian hearts regenerate through coordinated remodeling and proliferation supported by a pro-regenerative immune environment, extracellular matrix (ECM), and immature cardiomyocytes, including trabecular subtypes. Here, we establish a modular human cardioid injury platform to dissect these interactions. We show that anti-inflammatory macrophages selectively migrate to the injury, clear debris, and promote ECM remodeling, whereas inflammatory macrophages suppress cardiomyocyte proliferation. Synergistic FGF2-NRG1 signaling induces trabecular identity and morphology in a hyaluronan-dependent manner, conferring enhanced injury repair, characterized by cytoskeletal remodeling and cardiomyocyte proliferation mediated by YAP and WNT signaling. Exogenous YAP, but not WNT, is sufficient to promote repair in non-trabecular cardioids. These findings uncover coordinated immune-ECM-cardiomyocyte interactions governing human fetal regenerative competence and mechanistically resolve remodeling and proliferative components of cardiac repair. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=162 SRC="FIGDIR/small/735236v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@7ff079org.highwire.dtl.DTLVardef@184d5bdorg.highwire.dtl.DTLVardef@1ec775borg.highwire.dtl.DTLVardef@190008e_HPS_FORMAT_FIGEXP M_FIG C_FIG

Rupture of the fibrous cap is the primary cause of clinical complications from atherosclerosis. Smooth muscle cells (SMCs) are a major contributor to fibrous cap development and stability through de-differentiation to extracellular matrix-producing cells. We previously showed that the antioxidant enzyme cytoglobin (CYGB) is expressed in vascular SMCs and regulates SMC dependent vascular remodeling and gene expression. In the present study, we investigated the function of SMC-CYGB in atherosclerosis. To this end, we generated a mouse line with SMC-specific deletion of Cygb and simultaneous SMC-lineage tracing. We found that SMC specific deletion of CYGB increased fibrous cap thickness in a 17-week PCSK9-AAV8 gain of function combined with Western diet mouse model of atherosclerosis. SMC specific deletion of CYGB increased collagen deposition and SMC cellularity of the fibrous cap in the absence of changes in total plaque and necrotic core sizes. CYGB expression in SMCs was associated with transdifferentiation towards a fibroblast-like, matrix remodeling phenotype. Finally, CYGB was expressed in the fibrous cap of human coronary atherosclerotic lesions and was associated with ACTA2 positive cells. These results provide first-time evidence that SMC-CYGB reduces plaque stability by decreasing cap thickness, collagen deposition, and SMC cellularity.

BackgroundAdipose tissue surrounding the heart and vasculature plays critical roles in cardiovascular homeostasis and disease, yet the cellular and molecular milieu of these depots at single-cell resolution remains incompletely characterized. Understanding how regional adipocytes differ transcriptionally and communicate with neighboring cardiovascular cells is essential for developing targeted therapeutic strategies. MethodsWe performed single-nucleus RNA sequencing (snRNA-seq) on human adipose tissue from four anatomically distinct depots: ascending aorta, left atrium, right coronary artery, and subcutaneous fat. We characterized cellular composition, adipocyte and progenitor heterogeneity, depot-specific transcriptional programs, and intercellular communication networks. We further examined signaling remodeling in disease contexts, including atrial fibrillation and aortic aneurysm. ResultsWe identified six transcriptionally distinct adipocyte subpopulations and six adipocyte stromal and progenitor cell (ASPC) subpopulations were shared across depots but showed marked differences in abundance and gene expression reflecting developmental imprinting, including HOX family genes and anterior-posterior patterning programs. Intercellular communication analysis revealed depot-specific ligand-receptor interactions, with EPHA signaling identified as selectively enriched in the left atrial adipose depot. Disease-state analyses demonstrated extensive change in cell-cell communication in atrial fibrillation and aortic aneurysm, with differential regulation of FN1, EGF, SLIT, NOTCH, and CD46 signaling pathways. ConclusionsOur study reveals that cardiac and vascular adipose depots harbor transcriptionally specialized adipocytes and progenitors with distinct intercellular communication programs that are remodeled in atrial fibrillation and aortic aneurysm.

Endothelial senescence is increasingly recognized as a driver of vascular pathology, while immunoglobulin G (IgG) has recently been reported to accumulate in aging tissues and induce senescence in macrophages and microglia. In cerebral cavernous malformations (CCMs), IgG accumulation has been obviously observed in CCM lesions, but the contribution of IgG to endothelial injury remains unclear. Using multi-omic profiling, endothelial models, and CCM mice, we identified IgG-secreting plasma cells enriched in lesions associated with endothelial senescence, hemorrhage, and disease severity. CCM loss-associated mTOR activation impaired lysosomal acidification and IgG processing, promoting intracellular IgG accumulation. IgG, in turn, induced NF-kB-dependent endothelial senescence. In vivo, BCMA-mediated plasma cell depletion attenuated lesion progression, whereas IgG supplementation partially restored disease severity. Anti-CD38 treatment likewise reduced IgG accumulation, endothelial senescence, hemorrhage, and lesion progression. These findings identify lysosomal dysfunction-mediated IgG as a pathogenic trigger of endothelial senescence and support targeting the plasma cell-IgG axis in CCM.