Cardiovascular Research

BackgroundThoracic aortic aneurysm (TAA) is a life-threatening condition with an unpredictable lisk of rupture. Current clinical parameters have limited ability to accurately predict imminent rupture. Osteopontin (OPN) has been implicated in aortic aneurysm pathology, however, it role as a marker of imminent rupture remains. unclear. We investigated the dynamics of OPN expression dynamics in a mouse model with predictable rupture timing and validated our findings in human TAA. MethodsOne-month-old fibrillin-1 hypomorphic (Fbn1mgR/mgR) mice were used as a TAA model; with wild-type (WT) mice served as controls. Angiotensin II (AngII) was administered to Fbn1mgR/mgR to induce acute aortic rupture. Single-section transcriptome analysis and immunofluorescence staining were performed on ascending aortic tissue at 24 and 72 hours after AngII infusion, with pre-treatment Fbn1mgR/mgR and WT mice serving as controls. To determine conservation in human disease, we reanalyzed publicly available single-cell RNA sequencing data from ascending thoracic aortic aneurysm (ATAA) patients. ResultsAngII infusion induced progressive mortality beginning at 24 hours, with approximately 60% survival at 72 hours and nearly no survival by 8 days in Fbn1mgR/mgR mice. At this pre-rupture time point, OPN showed prominent upregulation at both mRNA and protein levels in ascending aortic tissues compared to controls. Immunofluorescence staining revealed increased OPN expression in the aortic wall, particularly in regions exhibiting structural deterioration. Reanalysis of human ATAA single-cell data showed elevated OPN expression compared to controls, with enrichment in immune cell populations, especially macrophages. Within the macrophage compartment, subcluster analysis identified a stress-responsive subpopulation (MC1) that was markedly expanded and almost exclusively composed of ATAA-derived cells, representing the primary source of OPN upregulation. ConclusionsOPN upregulation represents a conserved molecular signature of the pre-rupture state in TAA across mice and humans. Our mode, which enables predictable rupture timing, allowed the capture of acute pre-rupture molecular changes, suggesting OPN as a potential biomarker for predicting imminent aortic rupture.

BackgroundCarotid intima-media thickening (IMT) is a major risk factor for cardiovascular disease (CVD). The large ribosomal subunit protein 17 (Rpl17) was recently reported as a CVD-associated gene; however, ribosomal mutations generally are not associated with vascular dysfunction. We have created a novel genetic model of decreased RpL17 in endothelial cells (EC) to determine how changes in endothelial ribosome expression cause IMT. MethodsEC-restricted RpL17 heterozygous mice (Cdh5-Cre; RpL17fl/wt, or Rpl17-Het), were generated and subjected to sham or partial carotid ligation (PCL) surgery of the left artery to induce acute disturbed (d)-flow in vivo. Carotids were harvested on day 14 for quantitative tissue immunostaining. Purified mouse and human EC in vitro were exposed to steady (s)-flow or d-flow using cone viscometry, and collected for flow cytometry, protein expression, electron microscopy, or purification of ribosomes. Human carotid samples from healthy and endarterectomy patients were used for tissue analysis. ResultsCarotids from RpL17-Het mice with PCL-induced d-flow showed increased IMT relative to RpL17-WT controls. In addition, RpL17 protein levels were decreased in regions of d-flow compared to s-flow. Increased levels of ER stress markers were observed by carotid immunostaining, as well as activation of the integrated stress response (ISR) in RpL17-Het EC. Analysis of mRNAs bound to polysomes vs. monosomes in EC-RpL17-Het revealed increased translational efficiency of key regulators of glycolysis, redox, inflammation, matrix, and endothelial-to-mesenchymal transition (EndMT). Metabolic profiling by Seahorse assay showed enhanced anaerobic glycolysis and decreased oxidative respiration in RpL17-Het EC, consistent with the translational efficiency data. Immunostaining of carotids identified upregulated EC inflammation and EndMT. ConclusionsOur data support RpL17 as a key mediator of EC phenotypic modulation that causes IMT in response to d-flow. We show a novel pathway for d-flow-mediated IMT: endoplasmic reticulum stress and activation of the ISR. These changes alter translational efficiency and reprogram EC cell cycle, metabolism, and redox state in the presence of d-flow to cause IMT, a precursor to cardiovascular pathology.

Background: Pathologic aldosteronism induces oxidative stress, tissue injury, and increases in hemoglobin. Conversely, aldosterone antagonist therapy decreases hemoglobin. Whether these effects are attributable to aldosterone-mediated changes in iron and oxygen metabolism is unknown. Methods: The plasma proteome of participants with overt primary aldosteronism (PA) (n=50) was compared with participants without overt PA (n=61). To isolate aldosterone-dependent effects, participants without overt PA underwent oral sodium suppression testing to quantify the magnitude of renin-independent aldosterone production, enabling monotonic dose-response analyses across the continuum of renin-independent aldosteronism (subclinical to overt PA). Differential abundance testing was performed using empirical Bayes linear modeling, followed by Reactome pathway enrichment analysis and covariate-adjusted sensitivity analyses. To validate clinical relevance, aldosterone dose-response trends with blood count parameters were examined in this cohort, and an independent population-based cohort of 5,713 people with hypertension. Results: 903 proteins in the peripheral circulation were differentially abundant in overt PA versus participants without PA. The most significantly increased protein in overt PA was CYBRD1, involved in iron reduction and absorption. Pathway enrichment identified 16 iron- and heme-related pathways, including erythropoietin signaling, heme biosynthesis and mitochondrial iron-sulfur cluster biogenesis, with increases in heme and erythroid proteins and decreases in mitochondrial iron-sulfur proteins. Linear aldosterone dose-dependent trend analyses across the PA continuum further supported this signature, identifying progressive increases in hemoglobin subunits (HBA1/HBB), heme-related proteins (HMBS, UROS, AMBP, HPX, GLO1) and erythrocyte oxygen handling enzymes (CA1/CA3), alongside progressive reductions in mitochondrial electron transport chain subunits (CYCS, ETFA). These proteomic changes corresponded with aldosterone dose-dependent increases in red blood cell count, hemoglobin, and hematocrit, in this cohort and another population-based cohort. Conclusion: The continuum of PA is characterized by a progressive shift away from mitochondrial oxidative phosphorylation and toward increased intestinal iron absorption, preferential iron transport over storage, and enhanced heme synthesis and recycling, possibly reflecting cellular pseudohypoxia and systemic adaptations to increase oxygen delivery. These findings provide a novel mechanistic basis for aldosterone-mediated tissue injury and the benefits of aldosterone-directed therapy.

One major aftermath of COVID-19 pandemic is cardiovascular consequences. SARS-CoV-2 binds to ACE2 and downregulates vasodilation. Dengue favors hypotension by weakening endothelial glycocalyx leading to plasma leakage. C1q levels, immune complexes (ICs), and proteomic profiles in serum samples from 52 COVID-19 and 19 pre-pandemic Dengue cases were studied. Unlike Dengue, COVID-19 serums showed elevated coagulation proteins promoting vaso-occlusion and peripheral artery diseases. The stress-induced chaperone and atherosclerosis marker, GRP78 (gene/ protein) was found upregulated upon SARS-CoV-2 spike expression in cardiac/ lung cell lines. Elevated GRP78 levels were also observed in serum samples from COVID-19-diagnosed individuals and subjects with myocardial infarction (MI) in post COVID-era. Surprisingly, spike antibodies (Abs) showed cross-binding to GRP78 and possibly contributed to the observed higher-level ICs in COVID-19 serums (cardiovascular embolism?). Co-localization studies showed that spike Abs (analogous to pro-atherosclerotic GRP78 auto-Abs) could directly bind to upregulated cellular GRP78 (type II hypersensitivity?). Both pathways could worsen vascular injury and atherosclerosis, leading to cardiac complications in COVID-19 cases with narrowed vessels.

Intraplaque haemorrhage (IPH) is a hallmark of advanced atherosclerosis and a major risk factor for ischemic stroke and myocardial infarction. Current IPH classification focusses on extravascular erythrocyte presence as a proxy of acute bleeding, where iron detection generally indicates older haemorrhages. While often used interchangeably, a comprehensive analysis of transcriptional and metabolic context and impact of iron and erythrocyte deposition on the plaque is still lacking. Here, we investigate iron as a late-stage IPH hallmark in human atherosclerotic plaques. We analysed erythrocyte-rich, iron-rich, and non-IPH regions in human carotid endarterectomy plaques by re-analysing a published transcriptomic dataset of 43 patient samples. In addition, we performed histological and immune phenotyping to define plaque traits associated with iron versus erythrocyte accumulation. Finally, we performed spatial metabolic profiling to functionally define iron-rich regions. Although iron and erythrocyte deposits frequently co-localised, both co-related with different histological traits. While iron- and erythrocyte-rich regions shared transcriptomic features of advanced plaques compared with non-IPH regions, direct comparison showed differences in gene expression profiles. Iron deposition was associated with increased myeloid cell accumulation and a unique spatial metabolic signature distinct from erythrocyte-rich and non-IPH regions. While sharing many characteristics with IPH plaques, the molecular, cellular and metabolic landscape of iron-rich regions is marked by features of plaque remodelling and repair. This makes iron deposition a unique hallmark of late-stage IPH, extending the current erythrocyte-based definition of IPH.

BackgroundCalcific aortic valve disease (CAVD) is the most common valvular heart disease in developed countries, yet no pharmacological therapy is available to slow or halt its progression. CAVD is driven by progressive calcification of aortic valve leaflets, in which myeloid cells play a central role. While macrophages have been implicated in CAVD pathogenesis, the contribution of their precursors, monocytes, remains poorly understood. We hypothesized that circulating monocytes acquire a pro-calcific and pro-inflammatory phenotype contributing to valve remodelling and CAVD progression. MethodsWe profiled circulating CD14+ monocytes from healthy volunteers (Vol), patients with CAVD, and without CAVD (NCAVD). Peripheral blood mononuclear cells (PBMCs) were isolated, and monocyte subpopulations were phenotyped by flow cytometry. Transcriptome profiling by RNA sequencing identified disease-associated gene signatures, which were validated by RT-qPCR. The CD14+ monocyte secretome was analysed using multiplex assays. Functional ability of CAVD-derived CD14+ monocytes to induce myofibroblastic transdifferentiation (MT) and osteoblastic differentiation (OD) of human valvular interstitial cells (VICS) was evaluated by immunocytochemistry and quantitative o-cresolphthalein complexone assays. ResultsIn PBMCs, CAVD monocytes displayed a subpopulation shift, with an increased proportion of CD14CD16- classical monocytes and a reduced CD14CD16 non-classical monocyte levels. In CD14+ monocytes, transcriptomic analysis revealed upregulation of inflammation-related (PDK4) and calcification-related (ATP2B1) genes, alongside downregulation of immunomodulatory genes (DDR1, IKBKE). Secretome analysis showed reduced production of immunomodulatory and anti-osteoblastogenic cytokines (IL-4, CCL3) while promoting gene expression of factors promoting MT and OD in VICS. These alterations were associated with a marked monocyte-induced increase in SMA and OPN expression in VICS and a two-fold increase in calcification. ConclusionWe demonstrate for the first time that circulating monocytes from patients with CAVD exhibit enhanced pro-inflammatory and pro-calcific properties that may contribute to CAVD progression. Additionally, we identify dysregulated gene sets within these monocytes that represent potential novel therapeutic targets for CAVD.

Background: Hypoxia develops within growing atherosclerotic lesions, inducing nuclear translocation of hypoxia-inducible factor-1 (HIF1) and metabolic reprogramming. Its role in plaque macrophages and endothelial cells has been studied, but the hypoxic plaque interior is dominated by smooth muscle cell (SMC)-derived cells, for which the role of hypoxia signaling remains unclear. Here, we investigated how loss of Hif1a in SMC lineage cells impacts plaque progression and cell phenotype in murine atherosclerosis. Methods: Atherosclerosis was induced in mice with inducible SMC-specific deletion of Hif1a (Hif1aSMC-KO) and lineage tracing of SMC-derived plaque cells. Plaque size, necrotic core size, calcification, and SMC-derived cell phenotypes were quantified in aortic root sections and gene expression changes mapped by single-cell RNA sequencing. In parallel, a cultured SMC line with or without siRNA-mediated Hif1a knockdown was exposed to hypoxia for assessments of mitochondrial function and reactive oxygen species production. Results: Hif1aSMC-KO mice developed larger plaques, with expanded necrotic cores and increased calcification, compared with littermate controls. SMC-derived plaque cells were more abundant with a higher fraction of Col2a1+ chondromyocytes, and showed elevated markers of proliferation and apoptosis, whereas macrophage and endothelial cell numbers were unaffected. Single-cell RNA sequencing analysis revealed strong dysregulation of mitochondrial genes, including electron transport chain transcripts, along with upregulation of protein folding, proteasome, and oxidative stress response pathways. In cultured SMCs subjected to hypoxia, Hif1a silencing increased cell counts, aggravated mitochondrial proton leak, and led to the accumulation of depolarized, reactive oxygen species-generating mitochondria. Further analysis of SMC-derived cells in plaques from Hif1aSMC-KO mice confirmed increased oxidative stress by 8OHdG staining. Conclusions: HIF1 maintains mitochondrial function and restrains oxidative stress in SMC-derived plaque cells in murine atherosclerosis. Its chronic loss destabilizes redox homeostasis and promotes maladaptive SMC responses, leading to SMC-driven plaque expansion, necrosis, and calcification.

BackgroundInflammation is an emerging target for stroke prevention, but additional therapeutic candidates are needed. Experimental and observational studies implicate tumor necrosis factor (TNF) in atherosclerotic plaque progression and cardiovascular events. We integrated plasma proteomics from population-based studies and prospective stroke cohorts with single-cell and spatial transcriptomic profiling of human atherosclerotic plaque to investigate TNF signaling in stroke pathogenesis. MethodsWe assessed associations between 34 TNF-superfamily proteins (Olink Explore) and incident ischemic stroke among 47,529 UK Biobank participants without cardiovascular disease. We performed an individual-participant data (IPD) meta-analysis of four prospective cohorts with ischemic stroke (n=2,180) to examine associations between TNF- and recurrent vascular events. We characterised plaque-level TNF biology using single-cell RNA sequencing of 259,116 cells (62 donors) and Xenium spatial transcriptomics (12 donors) with human carotid plaques. ResultsIn UK Biobank, higher circulating TNF pathway proteins were independently associated with incident stroke after multivariable adjustment, including TNF, TNFR1, and TNFR2 (Hazard Ratio [HR] per SD increase, 1.14, [95% CI 1.07-1.20], 1.22, [1.14-1.31], and 1.15 [1.09-1.21], respectively. An additional 15 TNF superfamily members were also associated with incident stroke. In the IPD analysis of stroke cohorts, TNF- was associated with recurrent stroke (risk ratio [RR] 1.50, 95% CI 1.14-1.98, top vs. bottom third of TNF-) and MACE (RR 1.54, 1.18-2.02) after adjustment for cardiovascular risk factors and secondary prevention medications (537 MACE events, 6793 person-years follow up). In single-cell RNA plaque sequencing, TNF and TNF pathway genes were broadly expressed across immune cell populations. In spatial transcriptomics, TNF detection increased progressively from media to fibrous cap (Odds Ratio 2.32 vs media, 95% CI 1.94-2.78, p<0.001). At the fibrous cap, CD8+ effector T cells demonstrated 4.1-fold enrichment for TNF expression despite comprising only 3% of fibrous cap cells. ConclusionsTNF signaling is independently associated with incident ischemic stroke and recurrent MACE after stroke. TNF is enriched in human carotid plaque at the fibrous cap, in macrophages and CD8+ effector T cells. These results support evaluation of TNF-targeted therapies for stroke prevention.

AimsPlasminogen activator inhibitor-1 (PAI-1) regulates plasmin-mediated proteolysis, thereby influencing vascular stability and tissue remodeling. Angiotensin II (AngII) induces an increase in PAI-1 during the development of ascending thoracic aortic aneurysm (ATAA). The initial purpose of this study was to determine whether deletion of PAI-1 influenced development of ATAA. Subsequently, this study aimed to define the early pathological events preceding cardiac fibrosis in PAI-1 deficiency and the structural domain responsible for its protective effect. Methods and resultsAngII was infused for 4 weeks in whole-body PAI-1 deficient (PAI-1-/-) mice and their wild-type littermates (PAI-1+/+) to examine the role of PAI-1 in ATAA. PAI-1 deficiency did not alter AngII-induced aortopathy but revealed a striking cardiac phenotype characterized by replacement fibrosis predominantly within the epicardium and posterior septum. Ferric iron, indicative of prior hemorrhage, was coincident with fibrosis. Similar phenotypes were observed in PAI-1-/- mice infused with norepinephrine for 4 weeks. To define the pathological events preceding cardiac fibrosis, either AngII or norepinephrine was infused for 1 week in PAI-1+/+ or -/- mice. Both infusions induced extensive epicardial hemorrhage and posterior septal fibrosis in PAI-1-/- mice. To explore the initiation of cardiac pathology, AngII was infused for approximately 1 day. PAI-1-/- mice developed diffuse hemorrhage and cardiomyocyte injury localized to the posterior septum, pathologic changes that preceded overt fibrosis. Finally, to determine the protective domain of PAI-1, saline or AngII was administered to mice harboring loss-of-function point mutations in the protease inhibitory (PAI-1Ala/Ala) or somatomedin B-binding domains (PAI-1AK/AK). Compared to saline infusion, 1 week of AngII induced hemorrhage and heterogeneous fibrosis in PAI-1Ala/Ala, but not PAI-1AK/AK mice. ConclusionsThese findings support that, under hemodynamic stress, PAI-1 deficiency promotes early cardiac hemorrhage and cardiomyocyte injury that lead to fibrosis. Mutational studies implicate dysregulated plasmin generation as an initiator of cardiac injury and fibrosis. TRANSLATIONAL PERSPECTIVECardiac fibrosis has been reported in a human population with PAI-1 deficiency and currently lacks targeted therapy. Our findings demonstrate that in animal models, PAI-1 deficiency confers susceptibility to cardiac injury in response to hemodynamic stress, which may accelerate fibrotic remodeling. Mutational disruption of the protease-inhibitory domain of PAI-1 induced similar pathology, supporting a protective role for this function. These observations suggest that interventions aimed at controlling hypertension, promoting endothelial integrity, or regulating plasmin activation could reduce fibrotic remodeling in this population.

Introduction: Calcific aortic stenosis (CAS) is a progressive valvular disease characterized by lipid accumulation, inflammation, and osteogenic remodeling. Emerging evidence implicates gut microbiota-derived metabolites in cardiovascular pathology, yet their contribution to valvular disease remains poorly defined. The aim of this study was to investigate gut microbiota and metabolite signatures in patients with CAS and explore causal relationships using Mendelian randomization (MR). Methods: In a prospective cohort of 54 patients with CAS and 41 age, sex, BMI-balanced non-CAS controls, we performed integrated microbiome and metabolomic profiling. Gut microbial composition was assessed by 16S rRNA sequencing, and circulating levels of tryptophan derivatives, short-chain fatty acids, bile acids, and TMA/TMAO-related metabolites were quantified. MR analyses were performed to assess causal contributions of key metabolic and inflammatory markers to CAS. Results: Baseline characteristics were comparable between groups. CAS patients exhibited a distinct tryptophan metabolic profile, characterized by higher concentrations of inflammatory kynurenine-pathway metabolites and lower indole-3-sulfate. With consistent effect sizes despite modest statistical significance after multiple testing correction. Pathway-level analyses supported preferential routing of tryptophan toward inflammatory host metabolism. In contrast, global microbiota diversity and overall community structure were preserved. However, CAS was associated with depletion of specific Firmicutes taxa, including Eubacterium coprostanoligenes, a key cholesterol-converting bacterium mediating intestinal cholesterol-to-coprostanol transformation. MR analyses suggested LDL cholesterol and lipoprotein(a) as upstream triggers of CAS, whereas ALPL and tryptophan/kynurenine metabolites appear downstream and might reflect systemic inflammation and local metabolic consumption. Sex-stratified analyses revealed enhanced kynurenine pathway activation in males, whereas females exhibited relatively higher TMAO and indole-related metabolites. Conclusion: CAS is characterized by a focused gut-host metabolic reprogramming defined by inflammatory tryptophan catabolism and loss of cholesterol-transforming microbial functions, rather than global dysbiosis. These findings identify a potential gut, valve metabolic axis contributing to valvular calcification, with potential sex-specific effects.

BackgroundThe formation of a patent vascular lumen is fundamental to circulatory function, a process governed by cytoskeletal dynamics and mechanosensory signalling. Endothelial cilia are present during blood vessel lumen development, but their precise functional role remains poorly understood. Understanding how cilia coordinate with endothelial cytoskeletal and signalling pathways is critical for elucidating mechanisms of vascular morphogenesis. MethodsWe have established a microfluidic system that recapitulates endothelial tube formation under fluid flow, enabling pharmacological and genetic manipulation with real-time visualisation of tube behaviour. Cilia, cytoskeletal dynamics, and lumen development were analysed in vitro, and in vivo. ResultsEarly perfusion in the microfluidic system induced a hierarchical vascular network. Inhibiting Rho-kinase (ROCK) or knocking down ciliary components (IFT88 and RPGRIPL1) suppressed lumen formation. ROCK inhibition or genetic ablation disrupted cilia in endothelial and non-endothelial cells, associated with LIM-kinase inhibition. Crucially, ROCK2 genetic ablation caused endothelial cilia loss, misorientation, and abrogated lumen formation, leading to haemorrhages and compromised vascular integrity in vivo. ConclusionsOur findings unveil a previously unrecognised co-regulation between cilia and ROCK signalling essential in vascular lumen formation.

BackgroundEndothelial cell (EC) injury induced by disturbed flow drives neointimal hyperplasia in arteriovenous fistulas (AVFs), where CD34+ cell-mediated repair may be involved. PIEZO1 and VEGFR2 are important mechanosensors with critical role in maintaining endothelial function. However, whether PIEZO1 interacts with VEGFR2 during CD34+ cell differentiation to orchestrate the vascular repair remains unknown. MethodsAVF model was established in several mouse strains. Single cell RNA sequencing was performed for human and mouse samples. Cd34-CreERT2; R26-tdTomato; Piezo1flox/flox mice were used to investigate the effect of Piezo1 deletion on endothelial repair in AVFs. CD34-high human umbilical vein ECs (CD34high HUVECs) was sorted and exposed to different flow patterns to determine the role of shear stress in CD34high cell differentiation. Co-immunoprecipitation, proximal ligation assay and complementary approaches were performed to delineate mechanotransduction initiated by PIEZO1-VEGFR2 interaction. ResultsSingle cell RNA sequencing and immunostaining showed abundant CD34high cells in the vessel wall of AVFs in humans and animal models. Exposure of CD34high HUVECs to different flow patterns showed that laminar shear stress downregulated CD34 while upregulating VE-cadherin and claudin-5 expression. In contrast, oscillatory flow produced the opposite effects, indicating impaired endothelial maturation. PIEZO1 knockdown in CD34high HUVECs attenuated shear stress-induced endothelial marker expression. In Cd34 conditional Piezo1 knockout mouse model of AVF, we observed decreased number of CD34-derived cells, more compact cellular arrangement, and attenuated neointimal hyperplasia. Mechanistically, we found PIEZO1 interacts with VEGFR2, thereby mediating the distinct effects of laminar and oscillatory shear stress on AKT-FoxO1 axis, which critically regulates endothelial marker expression. Furthermore, pharmacological activation of AKT signaling in AVF mouse model enhanced CD34+ cell-mediated endothelial repair and attenuated neointimal hyperplasia. ConclusionPIEZO1-VEGFR2 complex-mediated mechanotransduction plays a key role in regulating CD34+ cell-derived endothelial repair in AVFs via AKT-FoxO1 axis. AKT activation enhances endothelial maturation, thereby attenuating neointimal hyperplasia in AVFs. Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIIn arteriovenous fistulas (AVFs), abnormal shear stress induces endothelial cell injury, and the resulting neointimal hyperplasia is a major cause of anastomotic stenosis. C_LIO_LICD34 cells actively participate in vascular endothelial repair. C_LIO_LIPIEZO1 is a mechanoreceptor mediating endothelial sensing of hemodynamic shear stress, contributing to the maintenance of atheroprotective endothelial phenotype under laminar shear stress, whereas its activation induces pro-inflammatory effects under disturbed shear stress. C_LI What New Information Does This Article Contribute?O_LICD34 cells participate in repairing endothelial injury induced by abnormal shear stress in AVFs. PIEZO1 knockout in CD34+ cells improve endothelial repair and attenuates neointimal hyperplasia in AVF. C_LIO_LILaminar shear stress induces CD34 downregulation and upregulates VE-cadherin and claudin-5 expression in CD34-high human umbilical vein endothelial cells, whereas oscillatory shear stress upregulates CD34 expression and suppresses VE-cadherin and claudin-5 expression. C_LIO_LIMechano-stimuli lead to PIEZO1-VEGFR2 complex formation regulating CD34 cell-mediated endothelial repair through the downstream AKT-FoxO1 axis. C_LI Abnormal hemodynamic shear stress-induced endothelial injury initiates neointimal hyperplasia in AVFs. The present study identifies PIEZO1 as a key mechanosensor that regulates CD34+ cell-derived endothelial repair in response to distinct blood flow patterns. PIEZO1 promotes CD34+ cell differentiation into mature ECs for endothelial repair under laminar shear stress, whereas it disrupts the differentiation of CD34+ cells into mature endothelium under oscillatory shear stress. Mechanistically, a novel shear stress-sensing complex comprising PIEZO1 and VEGFR2 was identified in regulating flow-induced differentiation of CD34+ cells into mature ECs via the AKT-FoxO1 signaling axis, thereby controlling the expression of endothelial maturation markers VE-Cadherin and Claudin-5. These findings define a novel PIEZO1-VEGFR2 mechanotransduction axis in CD34+ cell-mediated endothelial repair and support AKT pathway activation as a potential therapeutic strategy against neointimal hyperplasia in AVFs.

BACKGROUNDPatients with inflammatory bowel disease (IBD) are at increased risk of cardiovascular disease, yet the mechanisms linking chronic intestinal inflammation to cardiac dysfunction remain poorly understood. IBD is characterized by profound gut microbiota dysbiosis, which we hypothesize drives systemic immune dysregulation and contributes to cardiac dysfunction. METHODSA chronic colitis mouse model was used to assess gut microbiota dysbiosis, systemic immune cell metabolism, and cardiac remodeling. Cardiac outcomes were evaluated by echocardiography, histology, and molecular analyses. Mechanisms were examined using fecal microbiota transplantation, immune cell depletion, exosome transfer, bone marrow chimeras, RNA-seq, co-immunoprecipitation, confocal microscopy, and siRNA-mediated gene silencing. RESULTSChronic DSS colitis induced cardiac dysfunction, hypertrophy, and fibrosis in mice. These changes were accompanied by sustained gut microbiota dysbiosis, metabolic reprogramming, and mitochondrial dysfunction in circulating immune cells. Fecal microbiota transfer experiments demonstrated that colitis-associated microbiota were sufficient to reprogram systemic immune cells and promote cardiac dysfunction. Immune cell depletion studies identified macrophages as key mediators of colitis-associated cardiac injury. Colitis increased systemic lipopolysaccharide (LPS) translocation, bone marrow chimera experiments demonstrated that hematopoietic TLR4 signaling was required for immune cell metabolic remodeling and cardiac dysfunction during chronic colitis. Transcriptomic analysis identified guanylate-binding protein 2b (GBP2b/GBP1, hereafter referred to as GBP1) as a key downstream effector of LPS-TLR4 signaling. Upon LPS stimulation, GBP1 localized to mitochondria, where it interacted with DRP1 and FIS1 to promote mitochondrial fission, oxidative stress, and enhanced immune cell migration into the heart. In addition, GBP1 was secreted via exosomes, which were taken up by cardiomyocytes and contributed to hypertrophic remodeling, and cardiac dysfunction. CONCLUSIONSThese findings establish the LPS-TLR4-GBP1 axis as a key driver of colitis-associated cardiovascular dysfunction and highlight this pathway as a promising therapeutic target for reducing cardiovascular risk in patients with IBD. Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIPatients with inflammatory bowel disease have an increased risk of cardiovascular dysfunction that cannot be fully explained by traditional cardiovascular risk factors. C_LIO_LIGut microbiota dysbiosis and chronic innate immune activation are hallmarks of inflammatory bowel disease, but their direct contribution to cardiac remodeling remains unclear. C_LI What New Information Does This Article Contribute?O_LIChronic colitis-associated gut microbiota dysbiosis induces systemic immune cell metabolic and mitochondrial reprogramming that is sufficient to drive cardiomyocyte hypertrophy and cardiac dysfunction. C_LIO_LIHematopoietic Toll-like receptor 4 signaling links colitis associated gut microbiota to immune metabolic dysfunction and cardiac impairment, establishing a causal gut-immune-heart axis. C_LIO_LIGuanylate-binding protein 2b (GBP2b/GBP1) is identified as a critical downstream effector that promotes mitochondrial fission, oxidative stress, immune cell cardiac infiltration, and exosome-mediated cardiac remodeling. C_LI

BackgroundSuccessful pregnancy requires substantial maternal cardiovascular adaptation, including expansion and remodelling of the uterine arteries to support increased nutrient flow to the fetus. Hypertension is associated with impaired uterine artery remodelling and increased risk of fetal growth restriction and other adverse outcomes, yet the mechanisms driving vascular dysfunction in hypertensive pregnancy remain incompletely understood. Osteopontin, a matricellular protein, is implicated in vascular pathology in hypertension, positioning it as a candidate mediator of impaired uterine artery adaptation during hypertensive pregnancy. MethodsUterine artery remodelling was compared between pregnant normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive stroke-prone rats (SHRSP), a model of chronic hypertension. To determine the role of osteopontin in this process, an osteopontin-deficient SHRSP strain was characterized. Uterine artery blood flow was assessed by Doppler ultrasound, arterial structure was evaluated by histology, and molecular differences were identified by RNA sequencing. Fetal weight and length were measured at mid and late gestation. ResultsCompared with WKY, SHRSP fetuses were smaller, and uterine arteries exhibited inward hypertrophic remodelling, characterized by increased wall thickness, reduced lumen area, and elevated resistance index. SHRSP uterine arteries also showed increased expression of inflammatory and vascular pathology-associated genes, including osteopontin. In osteopontin-deficient SHRSP, uterine arteries had larger lumen areas, decreased resistance index, and reduced expression of inflammation-associated genes. Fetal growth was also improved in osteopontin-deficient SHRSP pregnancies. ConclusionsThese findings identify osteopontin as a contributor to impaired uterine artery adaptation and suggest that reduced osteopontin may improve vascular remodelling and fetal growth in hypertensive pregnancies.

BackgroundTissue vascularization relies on the organotypic specification of endothelial tip cells to interpret local cues and guide angiogenic sprouts into specific tissue compartments. However, the molecular regulators controlling brain and retinal endothelial tip cell identity remain poorly understood. MethodsEndothelial-specific Sox9 loss-of-function mouse was combined with single-cell, spatial, and bulk RNA sequencing analyses of developing mouse brain and retinal vasculature, as well as experimental ischemic stroke. Transcriptomic findings were validated using in situ hybridization, immunofluorescence, and functional angiogenesis assays. ResultsTranscription factor activity analysis of single-cell RNA-sequencing datasets identified SOX9 as a candidate regulator selectively enriched in developing brain and retinal endothelial tip cells. Endothelial-specific deletion of Sox9 impaired brain and neuroretina vascularization and disrupted the tip cell transcriptomic program, resulting in reduced sprouting angiogenesis and matrix-remodeling pathways. Conversely, SOX9 overexpression in HUVECs promoted neuro-tip-like signatures and enhanced endothelial invasion and sprouting. Following ischemic stroke, single-cell and spatial transcriptomic analyses identified a transient angiogenic endothelial population within the ischemic area. However, these cells failed to express Sox9 and lacked key developmental brain tip cell features. ConclusionsSOX9 is a key regulator of endothelial tip cell identity and neuronal angiogenesis. These findings reveal fundamental differences between developmental and injury-induced vascular responses and identify SOX9 as a potential therapeutic target to promote functional vascular regeneration.

BackgroundSuccinate has emerged as an immunometabolic mediator of cardiovascular diseases. However, the enzymatic mechanisms linking macrophage succinate metabolism to aortic dissection remain incompletely understood. This study investigated whether Suclg2, which encodes the GDP-forming {beta}-subunit of succinyl-CoA ligase, regulates succinate-associated macrophage remodelling and aortic dissection progression. MethodsSuclg2 expression was examined in BAPN-induced AD and human acute type A aortic dissection tissues by Western Blot and immunofluorescence. Myeloid- and smooth muscle cell-specific Suclg2 conditional knockout mice were subjected to BAPN treatment to evaluate survival, aortic outcomes, histological injury and aortic morphology. Aortic RNA-seq was used to discover transcriptional changes. Bone marrow-derived macrophages were analysed under basal, M1-like and M2-like conditions to assess macrophage-intrinsic transcriptional responses. Plasma succinate levels and untargeted metabolomic profiles were further examined. ResultsSuclg2 was increased in murine and human dissected aortas and partially localized to CD68 cells. Myeloid Suclg2 deletion markedly reduced BAPN-induced aortic rupture and dissection, whereas smooth muscle cell Suclg2 deletion did not confer comparable protection. Aortic transcriptomic analysis showed that myeloid Suclg2 deficiency attenuated inflammatory adhesion and matrix-destructive programmes. In macrophages, Suclg2 deletion did not induce a simple M1/M2 polarization shift; instead, it remodelled lipid-handling, phagolysosomal, adhesive and matrix-remodelling pathways across stimulation states. Metabolic profiling showed reduced circulating succinate and broader changes in central carbon, lipid-associated, nucleotide and redox-related metabolites after myeloid Suclg2 deletion. ConclusionsMyeloid Suclg2 is a succinate-associated immunometabolic regulator of aortic dissection. Its deficiency protects against aortic dissection by reshaping macrophage inflammatory-remodelling programmes and the systemic metabolic environment.

Following aortic dissection (AD), there is a sustained risk of vascular complications, progressive false lumen aneurysm formation, and rupture. However, no effective therapy exists to prevent these complications, highlighting the need to elucidate the pathophysiology following AD. Elastic fibers are crucial for maintaining aortic wall integrity but are thought to have limited regenerative capacity once disrupted during AD. This study defined that elastic fibers were newly generated in the false lumen wall following AD in humans and mice. In human ADs, new elastic fibers were observed in the false lumen wall 6 months after onset. In mice with descending AD induced by {beta}-aminopropionitrile (BAPN), elastin mRNA was markedly upregulated in the chronic phase following AD, accompanied by elastic fiber formation. These fibers coincided with smooth muscle cell (SMC) markers within the false lumen wall. Of note, lineage tracing studies demonstrated that these cells were not derived from resident SMCs but adventitial progenitor cells. In vitro experiments further demonstrated that adventitial progenitor cells produced elastic fibers while expressing SMC markers. Collectively, these findings suggest that adventitial progenitor cells differentiate into elastogenic SMC-like cells, contributing to false lumen remodeling through de novo elastic fiber formation following AD.

BACKGROUND: Individuals who develop coronary artery disease (CAD) are clinically and mechanistically heterogeneous, and understanding this variation is crucial for precise risk stratification and tailored interventions. However, the molecular mechanisms that connect these two kinds of heterogeneity remain unclear, limiting progress toward biologically grounded risk stratification and targeted interventions. Here, we investigated the heterogeneity of individuals who develop CAD by leveraging plasma proteomic signatures, placed individuals along continuous metabolic gradients and revealed the molecular programs underlying these patterns, thereby linking mechanistic variation to clinical heterogeneity. METHODS AND RESULTS: From 42,803 UK Biobank participants, including 3,713 individuals who developed CAD within 10 years (incident CAD), we first identified a 320-protein panel from 2,923 baseline proteins that improved prediction of incident CAD beyond clinical risk scores. Using reverse graph embedding, we reduced the proteomic data to two dimensions and mapped each incident case onto the resulting two-dimensional latent proteomic space. These proteomic dimensions show significant associations with cardiometabolic and kidney-related clinical markers. The patterns were replicated in the EPIC-Norfolk study. Phenome-wide Cox regression analyses further linked these proteomic dimensions to 10-year incidence rates for various diseases, including type 2 diabetes, obesity, and chronic kidney disease (CKD). Furthermore, adding the proteomic dimensions to clinical variable-based Cox regression model improved prediction of 10-year incidence of CKD and other diseases, demonstrating the value of proteomic dimensions beyond conventional clinical risk factors. Moreover, individuals with prevalent CAD (diagnosed before proteomic sampling) exhibited high, metabolically adverse dimension values, indicating that these axes capture cumulative metabolic burden. Pathway enrichment analyses implicated altered extracellular matrix organization and immune programs among the proteins contributing to the proteomic dimensions. CONCLUSIONS: Our findings demonstrate that plasma proteomic signatures can dissect the heterogeneity of individuals who develop CAD in continuous phenotypic gradients, improve prediction of CAD and comorbidities, and map underlying biological mechanisms.

BackgroundAtherosclerosis is a chronic inflammatory vascular disorder with persistent residual inflammation even after standard lipid-lowering therapy. Mounting evidence from bench to bedside suggests that diabetes and obesity accelerate atherosclerosis development. Tirzepatide (TZP), a dual Glucagon-Like Peptide-1 Receptor/Glucose-Dependent Insulinotropic Polypeptide Receptor (GLP-1R/GIPR) agonist approved for treating diabetes and obesity, has demonstrated proven cardiometabolic efficacy in large cardiovascular outcome trials. However, it remains largely uncertain whether TZP attenuates atherosclerosis independent of its anti-diabetic and anti-obese effects through direct actions on the vasculature. MethodsWe established atherosclerotic mouse models under diabetic, obese, and non-diabetic/non-obese conditions. Analysis of covariance (ANCOVA) and pair-feeding experiments were applied to experimentally decouple weight-dependent metabolic improvement from intrinsic vasculoprotection. Molecular and cell biological assays in human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs) were performed to dissect the underlying signaling mechanisms. ResultsTZP markedly reduced aortic plaque burden and inflammation, restrained necrotic core enlargement, and improved plaque stability across all experimental mouse models. Both ANCOVA and pair-feeding experiments confirmed that these atheroprotective effects were independent of food intake and body weight loss. Furthermore, TZP attenuated systemic and vascular inflammation in Tumor Necrosis Factor- (TNF)-treated C57BL/6J mice, and this protection occurred without changes in body weight or blood glucose levels. Mechanistically, TZP directly targeted endothelial cells and activated the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/endothelial nitric oxide synthase (eNOS) pathway, increased eNOS phosphorylation and nitric oxide bioavailability, consequently downregulating the expression of the pro-inflammatory adhesion molecules Vascular Cell Adhesion Molecule-1 (VCAM-1) and Intercellular Adhesion Molecule-1 (ICAM-1). ConclusionsTZP arrests atherosclerosis progression through weight loss-independent anti-inflammatory mechanisms. These findings implicate TZP as a promising therapeutic drug for mitigating residual vascular inflammation in patients with atherosclerotic cardiovascular disease (ASCVD), irrespective of glycemic status or obesity. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LITirzepatide exerts direct anti-atherosclerotic effects in preclinical mouse models of atherosclerosis under diabetic, obese, and non-obese conditions. C_LIO_LITirzepatide directly targets endothelial GLP-1R/GIPR and downstream cAMP/PKA/eNOS signaling pathway to suppress NF-{kappa}B-driven vascular inflammation, thereby uncovering a previously unrecognized vasculoprotective mechanism underlying its cardiovascular benefits C_LI What Are the Clinical Implications?O_LITirzepatide exerts direct vascular protective effects independent of body weight reduction, suggesting that its cardiovascular benefits may extend beyond glycemic control and obesity management. C_LIO_LITirzepatide may represent a promising therapeutic drug for addressing residual vascular inflammation in ASCVD patients, including those without overt diabetes or obesity C_LI

Chronic pressure overload induces cardiac hypertrophy and heart failure through coordinated alterations in proteome homeostasis, metabolism and sarcomere organisation. The muscle-specific -isoform of the nascent polypeptide-associated complex (skNAC) is essential for sarcomere assembly during development, but its role in adult hearts remains largely unknown. Here, we show that skNAC expression is reduced in hypertrophic cardiomyocytes, mouse models of pressure overload, and human hypertrophic hearts, in association with disease severity. Cardiomyocyte-specific skNAC deletion results in basal hypertrophy, systolic dysfunction, and premature death, and exacerbates pressure overload-induced heart failure. At the molecular level, skNAC associates with ribosomes and is required for sarcomere organisation maintenance, while its loss induces autophagy and ultrastructural defects. Integrated transcriptomic and proteomic analyses reveal early downregulation of metabolic gene expression despite increased abundance of corresponding proteins, indicating compensatory metabolic responses. Gain-of-function studies confirm a protective role against hypertrophy. Together, these data establish skNAC as a key regulator of cardiac proteome homeostasis and metabolic adaptation during pathological remodelling.