Inflammatory responses are associated with recruitment of monocyte-derived cells (Mdcs) into tissues. Although tissue-specific Mdc reprogramming is well established, how Mdc infiltration alters tissue metabolism remains unclear. Here, using a mouse neuroinflammation model coupled with genetic fate mapping, metabolomics and metabolite imaging, we identify that central nervous system (CNS) Mdc infiltration is associated with substantial metabolic changes and assign disease-linked metabolites therein. In particular, we found that increased arginine catabolism driven by lesion-associated arginase 1 (Arg1)-expressing Mdcs promoted oxidative damage, lipid accumulation and Mdc dysfunction. Genetic ARG1 deficiency within Mdcs during neuroinflammation increased extracellular arginine and was associated with rewiring of the CNS metabolic landscape, including attenuated disease-linked metabolites. This was accompanied by enhanced Mdc-driven anti-inflammation, regulatory T cell expansion and improved disease outcome. Opposing effects were observed following dietary arginine deficiency. Together, our work highlights key roles for Mdcs in CNS metabolism and reveals the pleiotropic beneficial effects of arginine in neuroinflammation.

Micro- and nanoplastics (MNPs) are increasingly detected in human tissues, yet their causal contribution to cardiovascular disease remains poorly understood. Here we show that oral exposure to polyethylene (PE) and polyvinyl chloride (PVC) -- the most abundant polymers found in human atheromas -- accelerates atherosclerosis in ApoE-/-mice through distinct, polymer-specific molecular mechanisms. While both polymers increased plaque burden and reduced contractile smooth muscle cell (SMC) markers, single-cell transcriptomic profiling revealed divergent phenotypic trajectories. PE exposure drives SMCs toward a chondromyocyte-like cell (CMC) state, characterized by upregulated osteogenic signaling and markedly increased vascular calcification. Conversely, PVC exposure promotes a fibromyocyte-like program associated with altered collagen metabolism and accelerated cell migration without enhancing calcification. These distinct SMC programs are reflected in the transcriptional signatures of symptomatic human carotid plaques, suggesting clinical relevance for polymer-specific vascular remodeling. Our findings establish a causal link between common environmental plastics and accelerated atherosclerosis, demonstrating that MNP-induced vascular risk is mediated by divergent SMC fate decisions. These results provide a mechanistic framework for assessing the cardiovascular impact of global plastic pollution and identifying potential therapeutic targets to mitigate MNP-associated vascular toxicity.

Background: Vascular diseases are a leading cause of mortality worldwide. Epidemiological data suggest significant sex-based differences in vascular disease risk, but the mechanisms underlying these differences remain unclear. Clinical observations indicate that key sex-specific differences may exist in the vessel wall. Hypothesis: We hypothesize that sex differences in vascular diseases are regulated by sex-specific epigenetic factors/features that alter cellular responses to pathologic triggers in the vessel wall. Methods: Single cell transcriptomic (scRNA-seq) and epigenetic (scATAC-seq) analyses were performed on male (M) and female (F) ApoE mice at different stages of atherosclerosis progression (0, 16 wks) to uncover sex-specific responses to vascular insult. Comparative analyses were performed on M and F human coronary arteries to identify biologically conserved sex-specific regulatory features shared between humans and mice. These features were integrated with human genetic data to identify the biological processes and regulatory regions driving sex-specific responses. Key findings were subsequently validated in vitro using primary human vascular cells. Results: Transcriptomic differences between M and F cells were most profound in smooth muscle cells (SMC) and fibroblasts in human and murine arteries. In mouse, the sex-specific transcriptomic differences drastically increased after high fat diet exposures, with number of differentially expressed genes increasing from 29 to 140 in SMC, and 63 to 181 in fibroblasts. Furthermore, we found F SMC to more readily undergo phenotypic modulation despite lower lipid levels. Gene set enrichment analysis showed increased pathways related to extracellular matrix organization and epigenetic modification, as well as key regulators of PDGF and TGFB signaling in mice and human female SMC. Additionally, scATAC-seq identified thousands of sex-specific differentially accessible regions enriching for human genetic signals of vascular diseases. In particular, X-escapee genes Kdm6a and Kdm5c were identified which may work in concert to alter the epigenetic landscape. Conclusion: This study reveals significant sex-specific, vascular cell-type specific transcriptional and epigenetic mechanisms in vascular disease. These findings provide insights into the genetic and molecular basis of sex differences in vascular diseases and potential therapeutic targets.

Background and Aims Osimertinib is a third-generation tyrosine kinase inhibitor targeting activating mutations of epidermal growth factor receptor with remarkable therapeutic efficacy against non-small cell lung carcinoma. However, its use has been limited by associated cardiotoxicity, primarily with heart failure. Herein, this study aims to better understand the mechanisms underlying osimertinib cardiotoxicity and explore cardioprotective strategies.Methods This study leverages an in vitro model of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) and a clinically relevant in vivo mouse model of osimertinib cardiotoxicity by co-employing transverse aortic constriction to mimic haemodynamic stress in cancer patients.Results Osimertinib treatment leads to significant contractile dysfunction in mice without cell death, inflammation, or fibrosis. By leveraging single-nucleus RNA sequencing of mouse heart tissues and in vitro assays of human iPSC-CMs, the study reveals significant downregulation of MYLK3 and a subsequent decrease in MYL2 phosphorylation with marked sarcomere disarray as the main mechanism of osimertinib cardiotoxicity. GATA4 is further identified as a putative target of osimertinib, connecting its decreased phosphorylation to repressed MYLK3 transcription. The reversibility of osimertinib-induced cardiac dysfunction upon discontinuation of osimertinib treatment supports the hypothesis that transient sarcomere disruption, rather than permanent cellular damage, serves as the key underlying mechanism. Finally, the myosin activator omecamtiv is shown to be effective in preventing osimertinib cardiotoxicity.Conclusions These findings suggest that osimertinib causes reversible cardiac dysfunction by disrupting MYL2 phosphorylation via GATA4 dephosphorylation-mediated suppression of MYLK3 and highlight the potential of myosin activation as a preventive or rescue strategy for osimertinib cardiotoxicity.

BACKGROUND:The vascular system is the largest organ in the body and underlies most chronic diseases, yet the molecular mechanisms that govern its plasticity remain poorly defined. METHODS:We applied single-cell proteomics in vascular disease, integrating it with single-cell transcriptomics to map protein regulation in healthy and Marfan syndrome aortas. RESULTS:This approach uncovered cell type-specific and cell state-specific proteins missed at the transcriptional level. Notably, we identified a decoupling of fibrillin-1 RNA and protein abundance, suggesting altered protein regulation as a potential contributor to aortic degeneration. Single-cell proteomics further resolved modulated smooth muscle cell states enriched for matrix effectors (AEBP1 [adipocyte enhancer binding protein 1], HTRA1 [high-temperature requirement A serine peptidase 1], FN1 [fibronectin 1]) and uniquely protein-level regulators (GLIPR2 [GLI pathogenesis-related 2], ITGB2 [integrin beta-2], and CD151 [cluster of differentiation 151 antigen]). CONCLUSIONS:Together, these findings establish the human single-cell proteomic atlas of the aorta, reveal altered FBN1 (fibrillin-1) protein regulation in both human and mouse Marfan syndrome, and position single-cell proteomics as a transformative framework for decoding vascular plasticity and identifying actionable effectors in disease.

Vascular diseases, including atherosclerotic disease, are the leading cause of mortality worldwide. Epidemiological data points to sex-based differences in vascular disease risk, but the pathophysiological mechanisms remain poorly understood. Clinical observations suggest these differences originate within the vessel wall, but the mechanism that governs these sex-specific difference is not known. We hypothesized that sex-specific vascular disease susceptibility arises from interactions between sex chromosome–encoded epigenetic regulators and environmental exposures such as cigarette smoke. To study this, male and female ApoE knockout mice were exposed to cigarette smoke for 7 weeks and fed high-fat diet (HFD) for 8 weeks (Exposed cohort). As a control cohort, the other set were only fed HFD for 8 weeks. Throughout the exposure period, weekly weights and blood pressures were obtained. The aortic roots and descending aortae were harvested and processed for single-cell transcriptomic analysis (scRNA-seq). The data was integrated with human genetic data to identify the biological processes and regulatory regions driving sex-specific responses. A set of the aortic root and descending aorta were also used for immunohistology. At the end of the exposure period, there was gross evidence of early plaque development in the aortic root and descending aorta. Differential gene expression analysis of each segmental cell population reveals increased sex differences in smooth muscle cells (SMCs) and fibroblasts, compared to other cell types present. Increased transcriptomic differences show up in both male and female SMCs and fibroblasts for smoking and high-fat diet exposure relative to HFD alone. Further, GSEA reveals over-enrichment of pathways related to epigenetic modifications in female cells, compared to male cells. Notably, the X-linked histone demethylase Kdm6a and Kdm5c emerged as a top differentially expressed gene in descending SMCs with strong sex-specific significance, while showing modest regulation in root-derived cells. Smoking exposure downregulated Kdm6a and Kdm5c for both the sex, females more than males, as compared to HFD only which further affected matrix remodeling pathway. This study reveals significant sex-specific, vascular cell-type specific transcriptional and epigenetic mechanisms in vascular disease and shows sex chromosome-encoded epigenetic modifiers, particularly Kdm6a and Kdm5c, as pivotal in vascular cell plasticity in atherosclerosis.

Vascular smooth muscle cells contribute to heritable coronary artery disease risk and undergo complex transitions to multiple disease-related phenotypes. To investigate the genetic basis of these trajectories, we develop a dense timecourse single-cell transcriptomic and epigenetic map of atherosclerosis in a murine disease model accompanied by high-plex in situ spatial data. Using temporal data and probabilistic fate modeling, we identify key transcription factors that drive cell state changes through a combination of network-based prioritization and in silico transcription factor perturbation. Parallel knockout studies of validated coronary artery disease gene Tcf21 uncover its molecular mechanisms in smooth muscle cell transition, due in part to a role regulating the transition of smooth muscle cells in the secondary heart field. Integrating the murine atlas with human coronary artery disease genetics pinpoint smooth muscle cell phenotypes that mediate disease risk, highlighting causal disease mechanisms. Together, these studies resolve atherosclerosis trajectories at single-cell resolution and identify genetic causal transcriptomic and epigenomic mechanisms of coronary artery disease risk.

BACKGROUND:Transthyretin cardiac amyloidosis (ATTR-CM) is a progressive, underdiagnosed cause of heart failure (HF). Diagnostic delays may increase cardiac injury at treatment initiation, but the relationship between delay and outcomes remains poorly defined. OBJECTIVES:The purpose of this study was to evaluate time from HF diagnosis to ATTR-CM diagnosis as a proxy for disease progression and its association with HF hospitalization (HFH) and mortality. METHODS:This retrospective cohort study used Medicare fee-for-service and Veterans Health Administration (VHA) data. We identified patients diagnosed with ATTR-CM between 2016 and 2022 using a validated algorithm based on diagnoses and medications. Time-to-diagnosis was defined as days between each patient's first HF diagnosis and first amyloid diagnosis. Using multivariable Cox models, we evaluated its association with death or HFH. RESULTS:We identified 7,770 Medicare beneficiaries and 2,557 Veterans with HF and ATTR-CM. Median age at diagnosis was 81 years in both cohorts (Medicare IQR: 76-86; VHA IQR: 74-87); women comprised 1,775 (22.8%) of Medicare and 13 (0.5%) of VHA patients. Median time-to-diagnosis was 494 days (IQR: 63-1,340) for Medicare and 490 days (IQR: 69-1,286) for VHA. After adjustment for sociodemographics, each 1-year delay was associated with a 7% increased risk of the primary outcome (Medicare HR: 1.07; 95% CI: 1.06-1.08; VHA HR: 1.07; 95% CI: 1.05-1.09). Results were similar after adjusting for comorbidities. CONCLUSIONS:Across 2 real-world populations, diagnostic delay in ATTR-CM is a clinically meaningful marker of disease progression, with longer delays associated with increased HFH and mortality.

Advances in single-cell and spatial assays have revolutionized the scale and resolution of molecular tissue profiling. Here we present MetaPlaq, a multimodal atlas of human atherosclerotic arterial beds comprising over a million cells across single-cell transcriptomics, epigenomics and high-resolution spatial expression assays. We map granular cell states and disease-relevant transcriptional programs within the native tissue context of coronary arteries. Furthermore, we map cardiovascular GWAS signals to smooth muscle cells (SMCs) and endothelial cells (ECs) and uncover the cis-regulatory architecture governing their phenotypic transitions. Our comprehensive epigenomic reference allowed us to build cell-specific enhancer-gene link maps and multimodal gene regulatory networks (GRNs) underlying disease-relevant states such as osteogenic SMCs and ECs undergoing mesenchymal transition. We also integrate SMC and EC disease-associated gene sets with GRNs to nominate key transcription factors such as PRRX1, BNC2 and ELK3 regulating atherosclerosis-relevant transcriptional programs. Finally, we layer single-cell and spatial modalities to fine-map GWAS variants with improved cell and anatomical context. We highlight candidate cell-specific regulatory mechanisms at less characterized CAD loci, including FGD5 and MCF2L in ECs. Together, this atlas represents an important step towards fully interpreting genetic risk loci and informing new therapeutic strategies for cardiovascular disease.

Importance:Genetic factors only explain ~50% of an individual's lifetime CAD risk. Workplace pollution exposure likely represents a significant, under-recognized, and modifiable contributor. Clarifying its independent effect - distinct from residential air pollution - could inform targeted prevention, clinical risk assessment, and policy strategies. Objective:To quantify the independent association between workplace pollution exposure and incident CAD, rigorously adjusting for canonical risk factors, genetic risk, socioeconomic deprivation index, and residential air pollution. Design Setting and Participants:A prospective cohort analysis of 103,599 adults in the UK Biobank with complete baseline employment history and specialized workplace environment surveys. Participants with prior CAD, or missing genetic information, canonical risk factor data, or residential air pollution measurements, were excluded. Exposure:Cumulative, self-reported duration of exposure to workplace pollutants (including dust, smoke, exhaust, chemicals, asbestos, paints, and pesticides), summarized as a percentile measure. Main Outcomes and Measures:Incident CAD. Associations were estimated using Cox proportional hazards models adjusted for demographics, comorbidities, CAD polygenic risk score, and residential air pollution metrics, accounting for competing death events. Results:The cohort (median age 64 years; 43% male) had high baseline prevalence of smoking (41%) and co-morbidities (hypertension 27%, hyperlipidemia 16%, diabetes 4.3%). Common exposures included smoke (56%), dust (39%), and chemicals (27%). Over a median 7.5-year follow-up, 4,327 CAD cases occurred. Compared to the low exposure group, high workplace pollution exposures showed a stronger unadjusted association with CAD (hazard ratio [HR], 1.51; 95% CI, 1.40-1.63) relative to residential air pollution (unadjusted HR, 1.23; 95% CI, 1.14-1.33). Importantly, in multivariable models, workplace pollution remained independently associated with higher CAD incidence (adjusted HR, 1.21; 95% CI, 1.03-1.41), robust to all adjustment. Significant specific drivers included paints, thinners or glues, diesel exhaust, fumes, asbestos, and dust. Conclusions and Relevance:Workplace pollution is confirmed as a robust, independent risk factor for incident CAD. Its association is demonstrably stronger than residential air pollution and persists despite comprehensive adjustment for genetic predisposition and traditional cardiovascular risk factors. These findings underscore the need to strengthen worker protections, integrate occupational history into clinical risk assessment, and prioritize mechanistic research into non-lipid pollution pathways.

BACKGROUND:Electronic cigarette (E-cig) use has reached epidemic proportions worldwide, yet its cardiovascular consequences remain poorly defined. While several lines of evidences in human epidemiological and animal studies suggest chronic aerosol exposure accelerates atherosclerosis; the cellular and molecular mechanisms underlying this pathological remain unknown. METHODS:We exposed hyperlipidemic mice to chronic e-cigarette aerosol inhalation and characterized the plaque cellular landscape by coupling SMC lineage tracing with single-cell transcriptomic/epigenomic profiling and histologic phenotyping. We subsequently leveraged human coronary artery smooth muscle cells (HCASMCs) to validate in vivo discovery and identified E-cig specific pathological signaling pathways relevant to human vascular disease risk. RESULTS:Chronic E-cig aerosol exposure accelerated atherosclerosis, increasing both SMC phenotypic modulation and plaque macrophage burden in a lipid-independent manner. Transcriptomically, SMCs are particularly more sensitive to E-cig than other vascular cell types. E-cig exposure reprogrammed SMCs toward a pro-calcifying, chondrogenic phenotype, thereby enhancing vascular ossification in vivo and in HCASMCs in vitro. Mechanistically, E-cig mediated SMC fate alteration occurs through activation of a glutamatergic/NMDAR signaling program, that increased NMDAR-dependent Ca2+ influx in a GRIN2A dependent manner. Notably, inhibition of GRIN2A mediated signaling reversed E-cig-induced pathological shifts in SMC phenotype. CONCLUSIONS:SMC chondrogenic reprogramming and subsequent vascular calcification are central to the detrimental cardiovascular consequences of E-cig exposure. Our findings implicate a GRIN2A-dependent glutamatergic/NMDAR signaling axis in SMC as a primary driver of this calcifying remodeling program. These findings define a SMC-specific vulnerability to E-cig aerosols and establish the GRIN2A/NMDAR pathway as potential therapeutic targets for mitigating E-cig-associated cardiovascular disease.

Smooth muscle cell (SMC) phenotypic modulation and proliferation are a conserved cellular response to vascular insult in the pathogenesis of atherosclerosis, aneurysm and vascular injury. Pan-SMC lineage tracing previously revealed that few SMCs oligo-clonally expand in these diseases, while the majority remain dormant. However, it remains unclear whether SMC clone selection is stochastic or predetermined. Understanding which SMCs expand, and how, could reveal major new therapeutic targets for vascular disease. Notch3 and Sox9 are critical for arterial SMC specification during development. Using tamoxifen-inducible lineage-tracing and scRNAseq, we characterised rare, distinct populations of medial SMCs retaining Notch3 and Sox9 expression in healthy adult vessels. Despite low baseline abundance, lineage-traced Notch3/Sox9 + SMC progeny combined to contribute over half of SMC-derived lesional cells, suggesting that oligo-clonal SMC expansion arises mainly from pre-determined progenitors rather than stochastically. Further, Notch3/Sox9+ SMCs showed distinct transcriptomic profiles at baseline and differing fates within the final lesion, suggesting differing roles in pathogenesis. At baseline, Sox9+ SMCs displayed downregulation of contractile markers and upregulation of a complement of genes typically only detected in lesional modulated SMCs, suggesting cell priming. Moreover, compared with other SMC-derived plaque cells, progeny of Notch3+ cells expressed a distinct inflammatory profile and were preferentially fated to the fibrous cap while avoiding chondrogenic transformation. Finally, at baseline, Notch3/Sox9+ progenitor abundance varied between arterial regions, with lower frequency of both in the athero-resistant descending aorta and a higher Sox9+:Notch3+ ratio in the brachiocephalic artery, which forms more calcified plaque relative to fibrous cap. Overall, these findings suggest that the distinct, prespecified SMC progenitor populations may play functional roles in governing plaque structure and ultimately disease risk.

Background: The global obesity epidemic is accompanied by a rise in cardiovascular diseases, yet its treatments can paradoxically raise disease risk. Peptide hormones are powerful regulators of energetic and hemodynamic homeostasis. While GLP1 discovery revolutionized obesity treatment, its analogs, such as semaglutide, are limited by unwanted side effects. BMP/Retinoid Acid Inducible Neural Specific 3 (BRINP3) is a gene expressed in adventitial fibroblasts that harbors genetic signals for both obesity and atherosclerotic diseases. BRP3 is a BRINP3-derived novel peptide and potent suppressant of appetite with fewer GLP1-related adverse effects and distinct cardiovascular actions. Approach: Apoe-/- mice received daily intraperitoneal vehicle, BRP3, or semaglutide during final 4 weeks on high-fat diet. We recorded body weight, food intake, and blood pressure, and assessed aortic root lesions by histology and scRNA-seq. We treated human vascular cells with BRP3 or semaglutide for transcriptomic and functional assays. Results: BRP3 reduced weight, blood pressure independent of weight, atherosclerotic plaque size, and plaque inflammatory cell content. Although semaglutide caused greater weight reduction, plaque size and inflammation were not significantly altered, suggesting additional BRP3-related benefits independent of weight loss. BRP3 and semaglutide elicited distinct transcriptional responses of vascular cells. BRP3 potently activated the mural cell transcriptional program in vascular SMCs that contribute to plaque formation. BRP3 robustly activated phospho-CREB signaling in mural cells and minimally in macrophages or endothelial cells. Bulk RNA-seq of acute and long-term BRP3 treatment showed extensive transcriptomic effects, while semaglutide elicited minimal changes. BRP3 altered activation of vascular SMCs, reducing their ability to recruit macrophages in transwell assays, distinct from semaglutide. Conclusion: BRP3 is a potent suppressant of appetite and a unique ligand that directly alters vascular SMCs’ transcriptomic program, favorably altering responses to pathological triggers. BRP3 combines anorexigenic efficacy with direct, vascular mural cell-specific actions that lower blood pressure independently of weight, reduce atherosclerotic burden, and attenuate plaque inflammation, distinguishing it from GLP1R agonists. These findings suggest BRP3 as a novel cardiometabolic therapeutic agent to simultaneously treat obesity and its most dreaded sequelae.

Background and Aims:Accurate classification of mitral stenosis (MS) remains a significant clinical challenge. This study aimed to develop an artificial intelligence (AI) framework to automatically detect clinically significant MS from echocardiography. Methods:We developed EchoNet-MS, an open-source end-to-end integrated approach combining video based convolutional neural networks to assess MS severity and differentiate rheumatic etiology from echocardiography and validated its performance across four cohorts. Results:EchoNet-MS was trained and validated in total of 431,612 videos from 44,671 studies from three different healthcare system. Combining assessments from multiple echocardiographic videos, the model was trained on a Kaiser Permanente Northern California (KPNC) cohort of 8,677 studies from 7,576 patients with a range of MS severity. The model was validated on a KPNC held-out test cohort (N=1,623) and a temporally distinct cohort (N=19,206), as well as Stanford Healthcare (SHC) cohort (N=3,333) and Cedars-Sinai Medical Center (CSMC) cohort (N=72,909). EchoNet-MS achieved excellent discrimination of severe MS with AUC 0.937 [95% CI: 0.913 - 0.958] in the KPNC held-out cohort, 0.994 [0.986 - 0.999] in the temporally distinct cohort, 0.991 [0.986 - 0.995] in SHC, and 0.973 [0.958 - 0.987] in CSMC. The model achieved excellent performance in classifying both rheumatic or non-rheumatic MS with AUC ranging from 0.890 and 0.967. Conclusions:EchoNet-MS accurately assesses MS severity and etiology using information from multiple echocardiographic views. Its strong performance generalizes robustly to external cohorts and shows potential as an automated clinical decision support tool.

BACKGROUND:Hypertrophic cardiomyopathy (HCM) affects 20 million individuals globally, with increased risk of sudden death and heart failure. Although cardiac myosin inhibitors show great promise as disease-specific treatment, current indications are for obstructive HCM. Obstruction is not always well characterized by echocardiography. Artificial intelligence might assist in the improving the underdiagnosis of left ventricular outflow tract (LVOT) obstruction. OBJECTIVES:The authors aimed to develop a deep learning model to detect LVOT obstruction from non-Doppler B-mode echocardiography. METHODS:We identified 2,396 patients with LVOT obstruction and 6,177 control patients matched by age, sex, and septal thickness. LVOT obstruction was defined as the presence of an LVOT gradient or systolic anterior motion of the mitral valve on final echocardiography report. A deep learning model was trained on non-Doppler apical 4-chamber B-mode echocardiographic videos to detect the presence of outflow obstruction identified later in the same study by spectral Doppler. We evaluated our model on held-out test sets from Cedars-Sinai Medical Center, Stanford Healthcare, and Kaiser Permanente Northern California. RESULTS:In a test set of 3,848 videos from Cedars-Sinai Medical Center, our model demonstrated strong performance, detecting LVOT obstruction with area under the receiver operating characteristic curve (AUC) of 0.858 (95% CI: 0.847-0.870). The model demonstrated generalizable performance in the Kaiser Permanente Northern California cohort with AUC of 0.817 (95% CI: 0.740-0.922) and Stanford Healthcare with AUC 0.836 (95% CI: 0.807-0.827). Performance was consistent across patient subgroups, including those with hyperdynamic left ventricular function, pre-existing valvular disease, and small left ventricular cavity size. CONCLUSIONS:In this study, we developed an artificial intelligence model to detect LVOT obstruction from standard apical 4-chamber videos, highlighting patients who may benefit from more detailed cardiac workup for obstructive HCM.

BACKGROUND:Smooth muscle cells (SMCs) are reported to contribute the majority of cholesterol-overloaded foam cells in human and mouse atheromas. However, the transcriptome, specific markers, and biologic itinerary of SMC foam cells relative to macrophage foam cells have not been determined. METHODS:Transcriptomic analysis by single cell RNA sequencing (scRNA-seq) was performed on fresh coronary segments from heart transplant recipients with early to intermediate stage atherosclerosis. The gene expression pattern of a putative cluster of SMC foam cells was compared to those of cultured SMCs loaded with either aggregated low density lipoprotein (agLDL) or cholesterol bound to methyl-β-cyclodextrin (Chol-MβCD). Candidate markers of SMC foam cells not expressed by macrophage foam cells were validated in ours and publicly available datasets, by spatial transcriptomics and by immunofluorescence microscopy of human atheromas. Pathway analysis was performed using Gene Set Enrichment Analysis Hallmark gene sets. RESULTS:SMC foam cells derived from fibromyocytes were tentatively identified using a panel of markers upregulated with in vitro cholesterol loading of SMCs. agLDL loading reproduced the same transcriptional profile, whereas Chol- MβCD did not reproduce any in vivo SMC state. Top genes highly represented in SMC foam cells included SERPINE1, encoding plasminogen activator inhibitor 1 (PAI-1) and CFH, complement factor H, which were validated in further human coronary scRNA-seq datasets, by Xenium spatial transcriptomics, and by immunofluorescence microscopy. Relative to macrophage foam cells, SMC foam cells exhibit a distinct biologic itinerary, including activation of extracellular matrix, coagulation and angiogenesis pathways. CONCLUSIONS:SMC foam cells, which are derived from fibromyocytes ("lipomyocytes"), exhibit unique markers and biologic programs that differ markedly from macrophage foam cells in atherosclerotic plaque development. Further understanding of the role of lipomyocytes and their expression of CFH and PAI-1 expression in plaque biology may offer novel therapeutic options to reduce ischemic cardiovascular disease.

Vascular smooth muscle cell (VSMC) diversification drives atherosclerotic coronary artery disease (CAD). Mechanisms governing these cell state transitions remain unclear. We applied multiomic single-cell profiling, epitope mapping, and spatial transcriptomics across 27 human coronary arteries, identifying fibroblast activation protein (FAP) as a marker of modulated VSMCs. Lineage tracing in mice indicated that FAP+ cells originate from Myh11+ VSMCs, and FAP PET imaging in CAD patients showed plaque uptake. FAP+ cells states resided in the macrophage-rich neo-intima. Therapeutically, we developed an anti-FAP bispecific T-cell engager, which reduced plaque burden and remodeled the stromal-immune microenvironment through T-cell clonal expansion. Our study delivers a single-cell and spatial atlas of human CAD, establishes FAP as a marker of modulated VSMCs, and highlights immunotherapy for lipid-independent targets.