Endothelial TGF-β signalling drives vascular inflammation and atherosclerosis

Endothelium-targeted NF-κB siRNA nanogel for magnetic resonance imaging and visualized-anti-inflammation treatment of atherosclerosis

Atherosclerosis-induced lethal cardiovascular disease remains a severe healthcare threat due to the limited drug efficiency and untimely prediction of high-risk events caused by inadequate target specificity of medications, incapable recognition of insensitive patients, and variable morphology of vulnerable plaques. Therefore, it is necessary to develop efficient strategies to improve the diagnosis accuracy and achieve visualized treatment of atherosclerosis. Herein, we establish an inflamed endothelium-targeted three-in-one nucleic acid nanogel system that can reverse the inflammatory state of endothelial cells (ECs) in plaques and simultaneously achieve real-time monitoring of the therapy process for efficient atherosclerosis diagnosis and treatment. For this purpose, contrast agent (Gd-DOTA) and VCAM-1-targeted peptide (VP) are first covalently conjugated onto DNA strands by click reaction respectively, which could self-assemble into Y-shaped structures (Gd-Y1 and VP-Y2 motifs) with magnetic resonance (MR) imaging and endothelium targeting capacities. Thereafter, NF-κB subunit p65-targeting siRNA (siNF-κB) is crosslinked with Gd-Y1 and VP-Y2 motifs to construct the endothelium-targeting nanogel platform. With contrast agents inside, the nanogel enables MR-based diagnosis and visualized therapy of atherosclerosis, providing accurate prognostic analysis and indications for treatment results, which ensures timely disclosure of insensitive individuals and avoids acute lethal events. By delivering siNF-κB to inflammatory endothelium, the nanogel significantly regresses plaques in both the aorta and carotid artery with reduced inflammation cytokines, collagens, macrophages, and apoptotic cells, providing a potential anti-inflammation strategy to treat atherosclerosis and avoid acute cardiovascular disease.

Isoforskolin, adenylate cyclase agonist, inhibits endothelial-to-mesenchymal transition in atherosclerosis

BACKGROUND

Atherosclerosis is a common chronic disease characterized by the formation of atheromatous plaques and endothelial dysfunction. Endothelial-to-mesenchymal transition (EndMT) has been identified as a crucial driver of atherosclerosis, with TGF-β serving as a pivotal mediator of EndMT. Isoforskolin (ISOF), derived from the plant Coleus forskohlii, is an effective activator of adenylyl cyclase (AC). AC can catalyze the production of cyclic adenosine monophosphate (cAMP), mediating various biological functions. Several phosphodiesterase (PDE) inhibitors that degrade cAMP have been clinically utilized in the treatment of atherosclerosis. However, the evidence regarding the efficacy and mechanisms of AC agonists in the treatment of atherosclerosis remains inadequate.

PURPOSE

In this study, our primary objective was to examine the therapeutic impact of ISOF on atherosclerosis and elucidate its potential mechanisms.

METHODS

Male ApoE-/- rats were fed a high-fat diet for 18 weeks and then administered ISOF by gavage continuously for 12 weeks. A cell model was established by injuring mouse aortic endothelial cells (MAECs) with ox-LDL. Oil Red O staining and Masson staining were used to assess the plaque area and content of collagen. Aortic vasodilatory function was analyzed using the DMT Myograph system. Immunofluorescence was used to determine the localization of CD31 and α-SMA. Proteomics analysis was utilized to identify potential pharmacological mechanisms of ISOF. Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to detect the mRNA expression levels of AC (1-10) in aortic tissue. AC activity and cAMP concentration were detected using specific kits. The CCK-8 assay, wound-healing, and transwell assays were used to measure cell viability and proliferation. Mechanistically, western blot analysis was used to detect candidate protein expression levels. Finally, the pharmacological knockdown of AC5 was employed to clarify the potential mechanism of ISOF.

RESULTS

ISOF effectively inhibited atherosclerotic plaque progression and improved aortic vasodilatory function in ApoE-/- rats fed a high-fat diet. At the cellular level, ISOF enhanced cell viability and proliferation of MAECs compromised by ox-LDL. These phenotypic improvements were attributed to the inhibitory effect of ISOF on endothelial-to-mesenchymal transition (EndMT); ISOF increased the expression of endothelial markers such as CD31 and E-cadherin while decreasing the expression of mesenchymal markers, including N-cadherin and α-SMA. Mechanistically, and consistent with the results of proteomic analysis, ISOF markedly inhibited the TGF-β/Smad3 signaling pathway both in vivo and in vitro. Furthermore, the expression levels of adenylyl cyclase 5 (AC5) were significantly higher than those of other AC isoforms in rat aorta. ISOF might upregulate the expression of AC5, subsequently activating downstream protein kinase A (PKA) but not cAMP-activated exchange protein-1 (EPAC1). However, when AC5 was silenced, the effects of ISOF on EndMT and the cAMP/PKA/TGF-β pathway were effectively abolished.

CONCLUSION

The study showed that ISOF effectively combats atherosclerosis by inhibiting EndMT through the regulation of the AC5-dependent cAMP/PKA/TGF-β axis. This finding suggests a potential promising therapeutic strategy for treating atherosclerosis.

The Crosstalk Between Endothelial Cells, Smooth Muscle Cells, and Macrophages in Atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory vascular disease closely tied to cellular metabolism. Recent genome-wide association study data have suggested the significant roles of endothelial cells, smooth muscle cells, and macrophages in the regression and exacerbation of AS. However, the impact of cellular crosstalk and cellular metabolic derangements on disease progression in AS is vaguely understood. In this review, we analyze the roles of the three cell types in AS. We also summarize the crosstalk between the two of them, and the associated molecules and consequences involved. In addition, we emphasize potential therapeutic targets and highlight the importance of the three-cell co-culture model and extracellular vesicles in AS-related research, providing ideas for future studies.

Involvement of USP7 in aggravating Kawasaki disease by promoting TGFβ2 signaling mediated endothelial-mesenchymal transition and coronary artery remodeling

Kawasaki disease (KD), characterized by systematic vasculitis, is a leading cause of pediatric heart disease. Although recent studies have highlighted the critical role of deubiquitinases in vascular pathophysiology, their specific contribution to KD remains largely unknown. Herein, we investigated the function of the deubiquitinase USP7 in both KD patients and a CAWS-induced KD murine model. USP7 expression level is increased both in HCAECs induced by KD sera and cardiac CD31+ endothelial cells of KD mice. Whereas knockout of USP7 increases the cellular proportion of endothelial cells and potentially attenuates the elevated EndoMT, fibrosis, and inflammation in cardiac tissue of KD mice, consistently with the in vitro experiment observed in HCAECs induced by TGF-β2. Mechanistically, USP7 interacts with SMAD2/3, enhancing their protein stability by removing the K48 ubiquitin chain from both proteins and preventing their proteasome degradation, thus increasing the p-SMAD2 levels and nuclear entry. Importantly, intraperitoneal injection of USP7 inhibitor, P22077 elicited a robust anti-EndoMT and anti-vascular inflammation effect in KD model mice. Therefore, our study uncovered a previously unrecognized function of increased USP7 in KD by augmenting TGFβ2/SMAD2/SMAD3 signaling, thus facilitating the transcription of genes implicated in the EndoMT, cardiac fibrosis, and vascular remodeling. Our finding suggests that USP7 could serve as a potential therapeutic target for the prevention and treatment of coronary artery lesions in KD and related vascular diseases.

Mechanisms of wogonoside in the treatment of atherosclerosis based on network pharmacology, molecular docking, and experimental validation

BACKGROUND

Atherosclerosis serves as the fundamental pathology for a variety of cardiovascular disorders, with its pathogenesis being closely tied to the complex interplay among lipid metabolism, oxidative stress, and inflammation. Wogonoside is a natural flavonoid extracted from Scutellaria baicalensis with a variety of biological activities, including anti-inflammatory, hypolipidemic, and cardiac function improvement properties. Despite these known effects, the specific role of wogonoside in the context of atherosclerosis remains to be elucidated.

PURPOSE

To validate the efficacy of wogonoside in the treatment of atherosclerosis and to investigate its possible therapeutic mechanisms.

METHODS

Network pharmacology was used to obtain the core targets and signaling pathways that may be efficacious in the treatment of atherosclerosis with wogonoside, which were validated using molecular docking and molecular dynamics simulations. To further validate the core targets in the signaling pathway, we performed in vivo experiments using apolipoprotein E (ApoE)-/- mice. This included pathological morphology and lipid deposition analysis of mouse aorta, serum lipid level analysis, Elisa analysis, oxidative stress analysis, reactive oxygen species (ROS) fluorescence assay, immunohistochemical analysis and protein blot analysis.

RESULTS

Predictions were obtained that wogonoside treatment of atherosclerosis has 31 core targets, which are mainly focused on pathways such as Toll-like receptor (TLR) signaling pathway and NF-kappa B (NF-κB ) signaling pathway. Molecular docking and molecular dynamics simulations showed that wogonoside has good binding properties to the core targets. In vivo experimental results showed that wogonoside significantly inhibited aortic inflammatory response and lipid deposition, significantly reduced the release levels of total cholesterol (TC), triglycerides (TG), low-density-lipoprotein cholesterol (LDL-C), oxidized low density (ox-LDL) and free fatty acid (FFA), and significantly inhibited the release of inflammatory factors TNF-α, IL-1β, IL-6 and oxidative stress in ApoE-/- mice. Further molecular mechanism studies showed that wogonoside significantly inhibited the activation of TLR4/NF-κB signaling pathway in ApoE-/- mice.

CONCLUSION

Wogonoside may be an effective drug monomer for the treatment of atherosclerosis, and its mechanism of action is closely related to the inhibition of the activation of the TLR4/NF-κB signaling pathway.

Atherosclerosis in diabetes mellitus: novel mechanisms and mechanism-based therapeutic approaches

Atherosclerosis is a disease of large and medium arteries that can lead to life-threatening cardiovascular and cerebrovascular consequences, such as myocardial infarction and stroke. Moreover, atherosclerosis is a major contributor to cardiovascular-related mortality in individuals with diabetes mellitus. Diabetes aggravates the pathobiological mechanisms that underlie the development of atherosclerosis. Currently available anti-atherosclerotic drugs or strategies solely focus on optimal control of systemic risk factors, including hyperglycaemia and dyslipidaemia, but do not adequately target the diabetes-exacerbated mechanisms of atherosclerotic cardiovascular disease, highlighting the need for targeted, mechanism-based therapies. This Review focuses on emerging pathological mechanisms and related novel therapeutic targets in atherosclerotic cardiovascular disease in patients with diabetes.

Reconceptualizing Endothelial-to-mesenchymal transition in atherosclerosis: Signaling pathways and prospective targeting strategies

BACKGROUND

The modification of endothelial cells (ECs) biological function under pathogenic conditions leads to the expression of mesenchymal stromal cells (MSCs) markers, defined as endothelial-to-mesenchymal transition (EndMT). Invisible in onset and slow in progression, atherosclerosis (AS) is a potential contributor to various atherosclerotic cardiovascular diseases (ASCVD). By triggering AS, EndMT, the "initiator" of AS, induces the progression of ASCVD such as coronary atherosclerotic heart disease (CHD) and ischemic cerebrovascular disease (ICD), with serious clinical complications such as myocardial infarction (MI) and stroke. In-depth research of the pathomechanisms of EndMT and identification of potential targeted therapeutic strategies hold considerable research value for the prevention and treatment of ASCVD-associated with delayed EndMT. Although previous studies have progressively unraveled the complexity of EndMT and its pathogenicity triggered by alterations in vascular microenvironmental factors, systematic descriptions of the most recent pathogenic roles of EndMT in the progression of AS, targeted therapeutic strategies, and their future research directions are scarce.

AIM OF REVIEW

We aim to provide new researchers with comprehensive knowledge of EndMT in AS. We exhaustively review the latest research advancements in the field and provide a theoretical basis for investigating EndMT, a biological process with sophisticated mechanisms.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review summarized that altered hemodynamics with microenvironmental crosstalk consisting of inflammatory responses or glycolysis, oxidative stress, lactate or acetyl-CoA (Ac-CoA), fatty acid oxidation (FAO), intracellular iron overload, and transcription factors, including ELK1 and STAT3, modulate the EndMT and affect AS progression. In addition, we provide new paradigms for the development of promising therapeutic agents against these disease-causing processes and indicate promising directions and challenges that need to be addressed to elucidate the EndMT process.

Salvianic acid A ameliorates atherosclerosis through metabolic-dependent anti-EndMT pathway and repression of TGF-β/ALK5 signaling

BACKGROUND

Endothelial-to-mesenchymal transition (EndMT) has been identified as a key factor to the initiation and progression of the pathogenesis of atherosclerosis (AS). Salvianic acid A (SAAS) is the primary water-soluble bioactive ingredient found in Salvia miltiorrhiza, is renowned for its therapeutic effects on cardiovascular diseases. However, the efficacy and mechanisms of SAAS in treating EndMT-induced AS remain underexplored.

PURPOSE

This study aimed to investigate the role SAAS in reversing EndMT process to impede AS development.

METHODS

We used a murine model of cholesterol-rich and high-fat diet-induced AS in ApoE-/- mice to evaluate the effect of SAAS on EndMT during AS progression in vivo. The biological effects of SAAS on EndMT-induced HUVEC cells were also detected by transcriptome sequencing (RNA-seq). Mechanistic exploration was carried out using omics data mining and screening, gene knockout experiments, gene expression, protein expression, and localization of key gene expression in animal lesion areas.

RESULTS

We found that SAAS treatment significantly alleviated EndMT injury in the AS mice model and also improved aortic root lesions and dyslipidemia. Furthermore, pre-treatment with SAAS effectively inhibited the EndMT in HUVEC cells, as evidenced by maintained endothelial cell morphology and reduced cell migration ability, as well as elevated CD31 and decreased α-SMA. RNA sequencing data indicated that key differentially expressed genes were mainly enriched in metabolism-related and TGF-β receptor signaling pathways. The metabolic regulator PDK4 and profibrotic TGF-β receptor ALK5 were identified specifically. Subsequently, RT-qPCR and western blot results demonstrated that SAAS notably increased metabolic regulator PDK4 and decreased profibrotic TGF-β receptor ALK5 in EndMT-induced HUVEC cells. Moreover, siRNA-directed PDK4 inhibition resulted in EndMT induction and SAAS mediated the suppression of EndMT in a PDK4-dependent manner. Additionally, SAAS partially reduced the TGF-β receptor ALK5 expression. Furthermore, ApoE-/- AS mice with SAAS treatment displayed downregulation of ALK5 and upregulation of PDK4 with reduced EndMT during AS.

CONCLUSION

This investigation demonstrated that SAAS improved AS through metabolic-dependent anti-EndMT pathway and repression of profibrotic TGF-β receptor signaling, thereby providing SAAS as a promising therapeutic candidate for managing AS and EndMT-related disorders.

TGF-β1-induced apoptosis in retinal endothelial cells is implicated in retinal vein occlusion

Retinal vein occlusion (RVO) is a serious vascular condition that impairs vision due to retinal endothelial cell injury and apoptosis. This study aimed to identify key molecular pathways and therapeutic targets involved in RVO pathogenesis. Transcriptomic analysis of the retinal tissues from a mouse RVO model was performed to identify differentially expressed genes and co-expression modules associated with RVO. Protein-protein interaction network analysis pinpointed putative hub genes. In vitro experiments using human retinal microvascular endothelial cells (HRMECs) validated the involvement of identified genes/pathways in apoptosis induced by oxygen-glucose deprivation/reperfusion (OGD/R) and UV exposure. Gene expression was assessed by RT-qPCR, while protein levels and phosphorylation were measured by ELISA and Western blotting. Apoptosis was evaluated using flow cytometry, and reactive oxygen species (ROS) were quantified using a fluorescence-based assay. A total of 392 genes were identified as putatively involved in RVO-associated apoptosis, enriched in MAPK, TGF-β and other signaling pathways. Among top hub genes, TGF-β1 emerged as a central regulator whose expression and signaling (pSmad2/3) increased after OGD/R induction or UV exposure in HRMECs. TGF-β1-induced HRMEC apoptosis was mediated by p38/JNK activation. Similar effects were observed for OGD/R and UV triggering TGF-β1-dependent p38/JNK signaling and apoptosis. Pharmacological inhibition of TGF-β signaling attenuated the apoptotic and oxidative stress responses induced by OGD/R and UV exposure. This study elucidates TGF-β1 as a crucial mediator of retinal endothelial injury through p38/JNK-induced apoptosis, suggesting TGF-β1 pathway inhibition as a potential therapeutic strategy for RVO.

Circulating tumor cells shed large extracellular vesicles in capillary bifurcations that activate endothelial and immune cells

Circulating tumor cells (CTCs) and their clusters are the drivers of metastasis, but we have an incomplete understanding of how they interact with capillary beds. Using microfluidic models mimicking human capillary bifurcations, we observed cell size- and bifurcation-dependent shedding of nuclei-free fragments by patient CTCs, CTC-derived explant cells and numerous cancer cell lines. Shedding reduced cell sizes up to 61%, facilitating their transit through bifurcations. We demonstrated that shed fragments were a novel subclass of large extracellular vesicles (LEVs), "shearosomes", that require shear stress for their biogenesis and whose proteome was associated with immune-related pathways. Shearosomes exhibited functions characteristic of previously identified EVs including cell-directed internalization by endothelial and immune cells, and intercellular communication abilities such as disruption of endothelial barrier integrity, polarization of monocytes into M2 tumor-promoting macrophages and interactions between endothelial and immune cells. Cumulatively, these findings suggest that CTCs shed shearosomes in capillary beds that drive key processes involved in the formation of pre-metastatic niches.

The role of Epsins in atherosclerosis: From molecular mechanisms to therapeutic applications

Atherosclerosis is a multifaceted disease characterised by chronic inflammation and vascular remodelling, leading to plaque formation and cardiovascular complications. Recent evidence highlights the critical role of epsins, a family of endocytic proteins, in the pathogenesis of atherosclerosis. This manuscript explores the multifarious functions of epsins in atherosclerosis, focusing on their involvement in angiogenesis, lymphangiogenesis, and the modulation of key signalling pathways. We discuss how epsins facilitate EndoMT through their interaction with the TGFβ signalling pathway, which contributes to vascular smooth muscle cell-like phenotypes and plaque instability. Additionally, we examine the therapeutic potential of targeting epsins, elucidating their interactions with crucial partners such as LDLR, LRP-1, and TLR 2/4, among others, in mediating lipid metabolism and inflammation. Furthermore, we highlight the promising prospects of epsin-targeting peptides and small interfering RNAs as therapeutic agents for atherosclerosis treatment. Despite these advancements, the research faces limitations, including a reliance on specific mouse models and a need for comprehensive studies on the long-term effects of epsin modulation. Therefore, future investigations should focus on elucidating the detailed mechanisms of epsin function and their implications in cardiovascular health, fostering collaborations to translate basic research into innovative therapeutic strategies. This work underscores the necessity for further exploration of epsins to unlock their full therapeutic potential in combating atherosclerosis and related cardiovascular diseases.

Trimethylamine N-oxide promotes PERK-mediated endothelial-mesenchymal transition and apoptosis thereby aggravates atherosclerosis

The endothelial-mesenchymal transition (EndMT) is involved in the development of atherosclerosis (AS) and is a key process in vascular endothelial injury. Oxidative stress, inflammation, and apoptosis are common causes of EndMT, and EndMT progression can further accelerate the development of AS. The metabolite trimethylamine N-oxide (TMAO) is produced by the gut microbiome and is implicated in the development of several diseases, including diabetes and chronic kidney disease. However, the impact of TMAO on transforming growth factor β1(TGF-β1)-induced EndMT remains unclear. We hypothesize that TMAO exacerbates plaque formation and cardiac function impairment by promoting EndMT. Herein, we showed that high serum TMAO levels caused plaque formation, cardiac function damage and haemodynamic changes in ApoE-/- mice. In vitro, TMAO upregulated mesenchymal markers and downregulated endothelial markers in HAECs. Furthermore, TMAO increased the migratory capacity of EndMT cells. Mechanistically, we found that PERK downregulation could alleviate TMAO-induced oxidative stress, EndMT, plaque formation and cardiac function damage. Further study showed that activated transcription factor 3 (ATF3), the downstream molecule of protein kinase RNA-like endoplasmic reticulum kinase (PERK), could bind with TGF-β1/2 and affect EndMT. Overall, TMAO promotes EndMT, possibly through the PERK-eIF2α-ATF4-CHOP or the PERk-eIF2α-ATF3-TGF-β signalling pathways.

The dichotomic role of cytokines in aging

The chronic inflammation present in aged individuals is generally depicted as a detrimental player for longevity. Here, it is discussed several beneficial effects associated with the cytokines that are chronically elevated in inflammaging. These cytokines, such as IL-1β, type I interferons, IL-6 and TNF positively regulate macroautophagy, mitochondrial function, anti-tumor immune responses and skeletal muscle biogenesis, possibly contributing to longevity. On the other side, the detrimental and antagonistic role of these cytokines including the induction of sarcopenia, tissue damage and promotion of tumorigenesis are also discussed, underscoring the dichotomy associated with inflammaging and its players. In addition, it is discussed the role of the anti-inflammatory cytokine IL-10 and other cytokines that affect aging in a more linear way, such as IL-11, which promotes senescence, and IL-4 and IL-15, which promotes longevity. It is also discussed more specific regulators of aging that are downstream cytokines-mediated signaling.

The positive implication of natural antioxidants on oxidative stress-mediated diabetes mellitus complications

The complementary intervention to modulate diabetes mellitus (DM) metabolism has recently brought the global attention, since DM has become among the global burden diseases. Where, several related pathways elevate the production of superoxide in consequences. For example, the flux of glycation-derived end products (AGEs) could lead to the deactivation of insulin signaling pathways. In that context, many vitamins and phytochemicals in natural sources have high antioxidant impacts that reduce oxidative stress and cell damages. These chemicals could be applied as bioactive antidiabetic agents. Their mode of actions could be from regulating the intracellular reactive oxygen species (ROS) which cause several pro-inflammatory pathways related to the oxidative stress (OS) and DM. Besides, they have a great potential to control the epigenetic mutations and hyperglycemia and help in back the blood glucose to the normal level. Therefore, the current review addresses the important role of natural functional antioxidants in DM management and its association with its OS complications.

Aucubin ameliorates atherosclerosis by modulating tryptophan metabolism and inhibiting endothelial-mesenchymal transitions via gut microbiota regulation

BACKGROUND

The gut microbiota is believed to influence atherosclerosis (AS), and Aucubin (Au), a natural compound found in the traditional Chinese medicine Eucommia ulmoides Oliver, is being explored as a potential treatment for cardiovascular disease. Yet, the specific impact of Au on AS through the gut microbiota remains unclear.

PURPOSE

This study aimed to highlight the potential of Au in improving AS by influencing gut microbiota and investigating its potential mechanisms by which it and its metabolites of gut microbiota regulate lipid metabolism, inflammation and endothelial dysfunction.

METHODS

The impact of Au on AS in ApoE-/- mice was examined, followed by a fecal microbiota transplantation experiment to confirm the influence of Au on AS through gut microbiota. Subsequent analysis of fecal and serum samples using 16S rRNA gene sequencing and metabolomics revealed distinct features of gut microbiota and metabolites. Identified metabolites were then utilized in vivo experiments to investigate underlying mechanisms.

RESULTS

Au treatment effectively reduced dietary-induced dyslipidemia and endothelial dysfunction in a dose-dependent manner in atherosclerotic mice. It also improved vascular plaque accumulation and inflammation, increased aortic valve fibrous cap thickness, and decreased necrotic core and collagen fiber area. Subsequently, we observed a substantial increase in indole-3-acrylic acid (IAA), a microbe-derived metabolite, in cecal contents and serum, along with a significant rise in Lactobacillus abundance responsible for IAA production. Our findings demonstrated that IAA played a crucial role in alleviating AS. Furthermore, we discovered that IAA activated the Aryl hydrocarbon receptor (AhR) and suppressed the TGF-β/Smad pathway, potentially ameliorating endothelial-mesenchymal transitions in atherosclerotic mice.

CONCLUSION

These findings suggested that Au's anti-atherosclerotic effects were primarily due to elevated Lactobacillus-derived IAA, thereby potentially contributing to alleviating AS.

Chronic inflammation and vascular cell plasticity in atherosclerosis

Vascular smooth muscle cells, endothelial cells and macrophages undergo phenotypic conversions throughout atherosclerosis progression, both as a consequence of chronic inflammation and as subsequent drivers of it. The inflammatory hypothesis of atherosclerosis has been catapulted to the forefront of cardiovascular research as clinical trials have shown that anti-inflammatory therapy reduces adverse cardiovascular events. However, no current therapies have been specifically designed to target the phenotype of plaque cells. Fate mapping has revealed that plaque cells convert to detrimental and beneficial cell phenotypes during atherosclerosis, with cumulative evidence highlighting that vascular cell plasticity is intimately linked with plaque inflammation, ultimately impacting lesion stability. Here we review vascular cell plasticity during atherosclerosis in the context of the chronic inflammatory plaque microenvironment. We highlight the need to better understand how plaque cells behave during therapeutic intervention. We then propose modulating plaque cell phenotype as an unexplored therapeutic paradigm in the clinical setting.

Endothelial TGF-β Signaling Regulates Endothelial-Mesenchymal Transition During Arteriovenous Fistula Remodeling in Mice With Chronic Kidney Disease

BACKGROUND

Arteriovenous fistulae (AVF) are the preferred vascular access for hemodialysis in patients with end-stage kidney disease. Chronic kidney disease (CKD) is associated with endothelial injury, impaired AVF maturation, and reduced patency, as well as utilization. Because CKD is characterized by multiple pathophysiological processes that induce endothelial-to-mesenchymal transition (EndMT), we hypothesized that CKD promotes EndMT during venous remodeling and that disruption of endothelial TGF (transforming growth factor)-β signaling inhibits EndMT to prevent AVF failure even in the end-stage kidney disease environment.

METHODS

The mouse 5/6 nephrectomy and aortocaval fistula models were used. CKD was created via 5/6 nephrectomy, with controls of no (0/6) or partial (3/6) nephrectomy in C57BL/6J mice. AVF were created in mice with knockdown of TGF-βR1/R2 (TGF-β receptors type 1/2) in either smooth muscle cells or endothelial cells. AVF diameters and patency were measured and confirmed by serial ultrasound examination. AVF, both murine and human, were examined using Western blot, histology, and immunofluorescence. Human and mouse endothelial cells were used for in vitro experiments.

RESULTS

CKD accelerates TGF-β activation and promotes EndMT that is associated with increased AVF wall thickness and reduced patency in mice. Inhibition of TGF-β signaling in both endothelial cells and smooth muscle cells decreased smooth muscle cell proliferation in the AVF wall, attenuated EndMT, and was associated with reduced wall thickness, increased outward remodeling, and improved AVF patency. Human AVF also showed increased TGF-β signaling and EndMT.

CONCLUSIONS

CKD promotes EndMT and reduces AVF patency. Inhibition of TGF-β signaling, especially disruption of endothelial cell-specific TGF-β signaling, attenuates EndMT and improves AVF patency in mouse AVF. Inhibition of EndMT may be a therapeutic approach of translational significance to improve AVF patency in human patients with CKD.

In Vitro Models of Cardiovascular Disease: Embryoid Bodies, Organoids and Everything in Between

Cardiovascular disease comprises a group of disorders affecting or originating within tissues and organs of the cardiovascular system; most, if not all, will eventually result in cardiomyocyte dysfunction or death, negatively impacting cardiac function. Effective models of cardiac disease are thus important for understanding crucial aspects of disease progression, while recent advancements in stem cell biology have allowed for the use of stem cell populations to derive such models. These include three-dimensional (3D) models such as stem cell-based models of embryos (SCME) as well as organoids, many of which are frequently derived from embryoid bodies (EB). Not only can they recapitulate 3D form and function, but the developmental programs governing the self-organization of cell populations into more complex tissues as well. Many different organoids and SCME constructs have been generated in recent years to recreate cardiac tissue and the complex developmental programs that give rise to its cellular composition and unique tissue morphology. It is thus the purpose of this narrative literature review to describe and summarize many of the recently derived cardiac organoid models as well as their use for the recapitulation of genetic and acquired disease. Owing to the cellular composition of the models examined, this review will focus on disease and tissue injury associated with embryonic/fetal tissues.

Erosion of the Atheroma: Wicked T Cells at the Culprit Site

PURPOSE OF REVIEW

There is a growing recognition of plaque erosion as a cause of acute coronary syndrome. This review aims to examine the potential involvement of T cells in this process.

RECENT FINDINGS

Immune-vascular interactions have been identified in the development of plaque erosions. Up to one-third of eroded plaques show evidence of active immune infiltration, with the presence of T cells. We propose that microerosions may frequently occur in association with the infiltration of T cells and macrophages in early atherosclerotic lesions. Healing of erosions could trigger the deposition of excessive extracellular matrix. The pro-inflammatory and cytotoxic actions of T cells, along with reduced endothelial integrity and other mechanisms, may subsequently give rise to clinical symptoms. To gain a better understanding of the role of T cells in plaque erosion, it is crucial to develop improved models for conducting controlled experiments and to study atherosclerosis in younger individuals.

Shear stress is uncoupled from atheroprotective KLK10 in atherosclerotic plaques

BACKGROUND AND AIMS

Physiological shear stress promotes vascular homeostasis by inducing protective molecules in endothelial cells (EC). However, physiological shear stress has been linked to atherosclerosis progression in some individuals with heightened cardiovascular risk. To address this apparent paradox, we hypothesized that diseased arteries may exhibit reduced responsiveness to the protective effects of physiological shear stress. Consequently, we compared the transcriptome of EC exposed to physiological shear stress in healthy arteries versus atherosclerotic conditions.

METHODS

Employing 3D light sheet imaging and computational fluid dynamics, we identified NOS3 as a marker of physiological shear stress in both healthy and atherosclerotic murine arteries. Single-cell RNA sequencing was performed on EC from healthy (C57BL/6) mice, mildly diseased (Apoe-/- normal diet) mice, and highly diseased (Apoe-/- high fat diet) mice. The transcriptomes of Nos3high cells (exposed to physiological shear stress) were compared among the groups.

RESULTS

Nos3high EC were associated with several markers of physiological shear stress in healthy arteries. Clustering of Nos3high EC revealed 8 different EC subsets that varied in proportion between healthy and diseased arteries. Cluster-specific nested functional enrichment of gene ontology terms revealed that Nos3high EC in diseased arteries were enriched for inflammatory and apoptotic gene expression. These alterations were accompanied by changes in several mechanoreceptors, including the atheroprotective factor KLK10, which was enriched in Nos3high EC in healthy arteries but markedly reduced in severely diseased arteries.

CONCLUSIONS

Physiological shear stress is uncoupled from atheroprotective KLK10 within atherosclerotic plaques. This sheds light on the complex interplay between shear stress, endothelial function, and the progression of atherosclerosis in individuals at risk of cardiovascular complications.

Collagen VIII in vascular diseases

Collagens have dual functions in the extracellular matrix (ECM), acting as both structural components and signaling molecules in matricellular communication. Although collagen molecules share a common triple helix motif, the supramolecular organization helps classify them into nearly 30 different types of collagens. Collagen type VIII is a non-fibrillar, short-chain, network-forming collagen that is expressed throughout the vasculature. Collagen VIII expression is aberrant in cardiovascular, lung, and renal disease, as well as in several different types of cancer. It plays active roles in angiogenesis, vessel injury repair, maintenance of arterial compliance, atherosclerotic plaque formation and stability modulation, fibrosis, and ECM remodeling. This review presents an overview of the characteristics of collagen VIII in vascular-related disorders, from clinical significance to laboratory studies, with a major focus on highlighting the signaling properties of collagen VIII in the vascular ECM. The expression patterns of collagen VIII in human diseases and experimental animal models highlight the protein's important yet underexplored functions. A deeper understanding of its mechanisms and downstream signaling pathways may pave the way for translational and tissue engineering applications of collagen VIII.

Morin, a matrix metalloproteinase 9 inhibitor, attenuates endothelial-to-mesenchymal transition in atherosclerosis by downregulating Notch-1 signaling

OBJECTIVE

Atherosclerotic cardiovascular disease poses a significant health challenge globally. Recent findings highlight the pivotal role of the endothelial-to-mesenchymal transition (EndMT) in atherosclerosis. Morin is a bioflavonoid mainly extracted from white mulberry, a traditional Chinese herbal medicine with anti-inflammatory and antioxidant properties. This study examines whether morin can alleviate atherosclerosis by suppressing EndMT and seeks to elucidate the underlying mechanism.

METHODS

We induced an in vitro EndMT model in human umbilical vein endothelial cells (HUVECs) by stimulating the cells with transforming growth factor-β1 (TGF-β1) (10 ng/mL) for 48 h. The in vivo experiments were performed in an atherosclerosis model using apolipoprotein E (ApoE)-/- mice fed with a high-fat diet (HFD). Mice in the intervention group were given morin (50 mg/kg) orally for 4 weeks. Molecular docking and microscale thermophoresis were assayed to understand the interactions between morin and matrix metalloproteinase-9 (MMP-9).

RESULTS

Morin inhibited the expression of EndMT markers in a dose-dependent manner in TGF-β1-treated HUVECs. Administering 50 μmol/L morin suppressed the upregulation of MMP-9 and Notch-1 signaling in TGF-β1-induced EndMT. Moreover, the overexpression of MMP-9 activated Notch-1 signaling, thereby reversing morin's inhibitory effect on EndMT. In the HFD-induced atherosclerotic ApoE-/- mice, morin notably reduced aortic intimal hyperplasia and plaque formation by suppressing EndMT. Furthermore, morin demonstrated a strong binding affinity for MMP-9.

CONCLUSION

Morin acts as an MMP-9 inhibitor to disrupt EndMT in atherosclerosis by limiting the activation of Notch-1 signaling. This study underscores morin's potential utility in the development of anti-atherosclerotic medication. Please cite this article as: He Y, Qin XX, Liu MW, Sun W. Morin, a matrix metalloproteinase 9 inhibitor, attenuates endothelial-to-mesenchymal transition in atherosclerosis by downregulating Notch-1 Signaling. J Integr Med. 2024; 22(6): 684-696.

Senoinflammation as the underlying mechanism of aging and its modulation by calorie restriction

Senoinflammation is characterized by an unresolved low-grade inflammatory process that affects multiple organs and systemic functions. This review begins with a brief overview of the fundamental concepts and frameworks of senoinflammation. It is widely involved in the aging of various organs and ultimately leads to progressive systemic degeneration. Senoinflammation underlying age-related inflammation, is causally related to metabolic dysregulation and the formation of senescence-associated secretory phenotype (SASP) during aging and age-related diseases. This review discusses the biochemical evidence and molecular biology data supporting the concept of senoinflammation and its regulatory processes, highlighting the anti-aging and anti-inflammatory effects of calorie restriction (CR). Experimental data from CR studies demonstrated effective suppression of various pro-inflammatory cytokines and chemokines, lipid accumulation, and SASP during aging. In conclusion, senoinflammation represents the basic mechanism that creates a microenvironment conducive to aging and age-related diseases. Furthermore, it serves as a potential therapeutic target for mitigating aging and age-related diseases.

PHACTR1 and APOC1 genetic variants are associated with multi-vessel coronary artery disease

BACKGROUND

Severe coronary artery disease (CAD) represents an advanced arterial narrowing, often associated with critical complications like myocardial infarction and angina. This study aimed to comprehensively investigate determinants of severe and multi-vessel CAD manifestations.

METHODS

One thousand nine hundred patients with severe and multivessel CAD (stenosis > 70%) were recruited along with 1,056 controls without stenosis. Associations using a genotyping panel comprising 159 Single Nucleotide Polymorphisms (SNPs) previously implicated in CAD pathogenesis were examined and these associations were replicated using the UK Biobank cohort (N = 29,970).

RESULTS

The investigation identified 14 genetic associations with severe CAD, of which 7 were also associated with multivessel disease. Notably, PHACTR1 SNP (rs9349379*G) showed a higher association with severe and multivessel CAD in individuals aged ≤ 65, indicating a higher risk of early disease onset. Conversely, the APOC1/APOE SNP (rs445925*T) is associated with reduced susceptibility to severe CAD and multivessel disease in individuals aged over 65, indicating a persistent negative association.

CONCLUSIONS

Following replication of the associations in the large UK Biobank dataset, it was found that patients carrying the rs9349379*G variant in the PHACTR1 gene are at risk of developing severe or multivessel disease. Conversely, the rs445925*T variant in APOC1/APOE is associated with reduced susceptibility to severe CAD and multivessel disease, highlighting the significance of this genetic variant in these specific CAD presentations. This study contributes to a better understanding of CAD heterogeneity, paving the way for tailored management strategies based on genetic profiles.

Stretch-induced damage in endothelial monolayers

Endothelial cells are constantly exposed to mechanical stimuli, of which mechanical stretch has shown various beneficial or deleterious effects depending on whether loads are within physiological or pathological levels, respectively. Vascular properties change with age, and on a cell-scale, senescence elicits changes in endothelial cell mechanical properties that together can impair its response to stretch. Here, high-rate uniaxial stretch experiments were performed to quantify and compare the stretch-induced damage of monolayers consisting of young, senescent, and aged endothelial populations. The aged and senescent phenotypes were more fragile to stretch-induced damage. Prominent damage was detected by immunofluorescence and scanning electron microscopy as intercellular and intracellular void formation. Damage increased proportionally to the applied level of deformation and, for the aged and senescent phenotype, induced significant detachment of cells at lower levels of stretch compared to the young counterpart. Based on the phenotypic difference in cell-substrate adhesion of senescent cells indicating more mature focal adhesions, a discrete network model of endothelial cells being stretched was developed. The model showed that the more affine deformation of senescent cells increased their intracellular energy, thus enhancing the tendency for cellular damage and impending detachment. Next to quantifying for the first-time critical levels of endothelial stretch, the present results indicate that young cells are more resilient to deformation and that the fragility of senescent cells may be associated with their stronger adhesion to the substrate.

The Role of Cardio-Renal Inflammation in Deciding the Fate of the Arteriovenous Fistula in Haemodialysis Therapy

Vascular access is an indispensable component of haemodialysis therapy for end-stage kidney disease patients. The arteriovenous fistula (AVF) is most common, but importantly, two-year failure rates are greater than fifty percent. AVF failure can occur due to a lack of suitable vascular remodelling, and inappropriate inflammation preventing maturation, or alternatively neointimal hyperplasia and vascular stenosis preventing long-term use. A comprehensive mechanistic understanding of these processes is still lacking, but recent studies highlight an essential role for inflammation from uraemia and the AVF itself. Inflammation affects each cell in the cascade of AVF failure, the endothelium, the infiltrating immune cells, and the vascular smooth muscle cells. This review examines the role of inflammation in each cell step by step and the influence on AVF failure. Inflammation resulting in AVF failure occurs initially via changes in endothelial cell activation, permeability, and vasoprotective chemokine secretion. Resultingly, immune cells can extravasate into the subendothelial space to release inflammatory cytokines and cause other deleterious changes to the microenvironment. Finally, all these changes modify vascular smooth muscle cell function, resulting in excessive and unchecked hyperplasia and proliferation, eventually leading to stenosis and the failure of the AVF. Finally, the emerging therapeutic options based off these findings are discussed, including mesenchymal stem cells, small-molecule inhibitors, and far-infrared therapies. Recent years have clearly demonstrated a vital role for inflammation in deciding the fate of the AVF, and future works must be centred on this to develop therapies for a hitherto unacceptably underserved patient population.

Anti-Inflammatory Oxysterol, Oxy210, Inhibits Atherosclerosis in Hyperlipidemic Mice and Inflammatory Responses of Vascular Cells

BACKGROUND AND AIMS

We previously reported that Oxy210, an oxysterol-based drug candidate, exhibits antifibrotic and anti-inflammatory properties. We also showed that, in mice, it ameliorates hepatic hallmarks of non-alcoholic steatohepatitis (NASH), including inflammation and fibrosis, and reduces adipose tissue inflammation. Here, we aim to investigate the effects of Oxy210 on atherosclerosis, an inflammatory disease of the large arteries that is linked to NASH in epidemiologic studies, shares many of the same risk factors, and is the major cause of mortality in people with NASH.

METHODS

Oxy210 was studied in vivo in APOE*3-Leiden.CETP mice, a humanized mouse model for both NASH and atherosclerosis, in which symptoms are induced by consumption of a high fat, high cholesterol "Western" diet (WD). Oxy210 was also studied in vitro using two cell types that are important in atherogenesis: human aortic endothelial cells (HAECs) and macrophages treated with atherogenic and inflammatory agents.

RESULTS

Oxy210 reduced atherosclerotic lesion formation by more than 50% in hyperlipidemic mice fed the WD for 16 weeks. This was accompanied by reduced plasma cholesterol levels and reduced macrophages in lesions. In HAECs and macrophages, Oxy210 reduced the expression of key inflammatory markers associated with atherosclerosis, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL2), vascular cell adhesion molecule-1 (VCAM-1), and E-Selectin. In addition, cholesterol efflux was significantly enhanced in macrophages treated with Oxy210.

CONCLUSIONS

These findings suggest that Oxy210 could be a drug candidate for targeting both NASH and atherosclerosis, as well as chronic inflammation associated with the manifestations of metabolic syndrome.

GDF3 promotes adipose tissue macrophage-mediated inflammation via altered chromatin accessibility during aging

Age-related susceptibility to sepsis and endotoxemia is poorly defined, although hyperactivation of the immune system and the expansion of the visceral adipose as an immunological reservoir are underlying features. Macrophages from older organisms exhibit substantial changes, including chronic NLRP3 inflammasome activation, genomic remodeling and a dysfunctional, amplified inflammatory response upon new exposure to pathogen. However, the mechanisms by which old macrophages maintain their inflammatory phenotype during endotoxemia remains elusive. We previously identified Gdf3 , a TGFβ superfamily cytokine, as a top-regulated gene by age and the NLRP3 inflammasome in adipose tissue macrophages (ATMs). Here, we demonstrate that endotoxemia increases inflammatory (CD11c + ) ATMs in a Gdf3- dependent manner in old mice. Lifelong systemic or myeloid-specific deletion of Gdf3 leads to reduced endotoxemia- induced inflammation, with decreased CD11c + ATMs and inflammatory cytokines, and protection from hypothermia. Moreover, acute blockade of Gdf3 using JQ1, a BRD4 inhibitor, phenocopies old mice with lifelong Gdf3- deficiency. We show that GDF3 promotes the inflammatory phenotype in ATMs by phosphorylating SMAD2/3. Mechanistically, the differential chromatin landscape of ATMs from old mice with or without myeloid-driven Gdf3 indicates that GDF3- SMAD2/3 signaling axis shifts the chromatin accessibility of ATMs towards an inflammatory state during aging. Furthermore, pharmaceutical inhibition of SMAD3 with a specific inhibitor of SMAD3 (SIS3) mimics Gdf3 deletion. SIS3 reduces endotoxemia-mediated inflammation with fewer CD11c + ATMs and less severe hypothermia in old, but not young mice, as well as reduced mortality. In human adipose tissue, age positively correlates with GDF3 level, while inflammation correlates with pSMAD2/3 level. Overall, these results highlight the importance of GDF3-SMAD2/3 axis in driving inflammation in older organisms and identify this signaling axis as a promising therapeutic target for mitigating endotoxemia-related inflammation in the aged.

Novel Role of Endothelial CD45 in Regulating Endothelial-to-Mesenchymal Transition in Atherosclerosis

Background

Protein-tyrosine-phosphatase CD45 is exclusively expressed in all nucleated cells of the hematopoietic system but is rarely expressed in endothelial cells. Interestingly, our recent study indicated that activation of the endogenous CD45 promoter in human endothelial colony forming cells (ECFCs) induced expression of multiple EndoMT marker genes. However, the detailed molecular mechanisms underlying CD45 that drive EndoMT and the therapeutic potential of manipulation of CD45 expression in atherosclerosis are entirely unknown.

Method

We generated a tamoxifen-inducible EC-specific CD45 deficient mouse strain (EC-iCD45KO) in an ApoE-deficient (ApoE-/-) background and fed with a Western diet (C57BL/6) for atherosclerosis and molecular analyses. We isolated and enriched mouse aortic endothelial cells with CD31 beads to perform single-cell RNA sequencing. Biomedical, cellular, and molecular approaches were utilized to investigate the role of endothelial CD45-specific deletion in the prevention of EndoMT in ApoE-/- model of atherosclerosis.

Results

Single-cell RNA sequencing revealed that loss of endothelial CD45 inhibits EndoMT marker expression and transforming growth factor-β signaling in atherosclerotic mice. which is associated with the reductions of lesions in the ApoE-/- mouse model. Mechanistically, the loss of endothelial cell CD45 results in increased KLF2 expression, which inhibits transforming growth factor-β signaling and EndoMT. Consistently, endothelial CD45 deficient mice showed reduced lesion development, plaque macrophages, and expression of cell adhesion molecules when compared to ApoE-/- controls.

Conclusions

These findings demonstrate that the loss of endothelial CD45 protects against EndoMT-driven atherosclerosis, promoting KLF2 expression while inhibiting TGFβ signaling and EndoMT markers. Thus, targeting endothelial CD45 may be a novel therapeutic strategy for EndoMT and atherosclerosis.

A systems view of the vascular endothelium in health and disease

The dysfunction of blood-vessel-lining endothelial cells is a major cause of mortality. Although endothelial cells, being present in all organs as a single-cell layer, are often conceived as a rather inert cell population, the vascular endothelium as a whole should be considered a highly dynamic and interactive systemically disseminated organ. We present here a holistic view of the field of vascular research and review the diverse functions of blood-vessel-lining endothelial cells during the life cycle of the vasculature, namely responsive and relaying functions of the vascular endothelium and the responsive roles as instructive gatekeepers of organ function. Emerging translational perspectives in regenerative medicine, preventive medicine, and aging research are developed. Collectively, this review is aimed at promoting disciplinary coherence in the field of angioscience for a broader appreciation of the importance of the vasculature for organ function, systemic health, and healthy aging.

TGF-β1 overexpression in severe COVID-19 survivors and its implications for early-phase fibrotic abnormalities and long-term functional impairment

Introduction

In post-COVID survivors, transforming growth factor-beta-1 (TGF-β1) might mediate fibroblast activation, resulting in persistent fibrosis.

Methods

In this study, 82 survivors of COVID-19-associated ARDS were examined at 6- and 24-months post-ICU discharge. At 6-months, quantitative CT analysis of lung attenuation was performed and active TGF-β1 was measured in blood and exhaled breath condensate (EBC).

Results

At 6-months of ICU-discharge, patients with reduced DmCO/alveolar volume ratio exhibited higher plasma and EBC levels of active TGF-β1. Plasma TGF-β1 levels were elevated in dyspneic survivors and directly related to the high-attenuation lung volume. In vitro, plasma and EBC from survivors induced profibrotic changes in human primary fibroblasts in a TGF-β receptor-dependent manner. Finally, at 6-months, plasma and EBC active TGF-β1 levels discriminated patients who, 24-months post-ICU-discharge, developed gas exchange impairment.

Discussion

TGF-β1 pathway plays a pivotal role in the early-phase fibrotic abnormalities in COVID-19-induced ARDS survivors, with significant implications for long-term functional impairment.

Pathophysiology in Brain Arteriovenous Malformations: Focus on Endothelial Dysfunctions and Endothelial-to-Mesenchymal Transition

Brain arteriovenous malformations (bAVMs) substantially increase the risk for intracerebral hemorrhage (ICH), which is associated with significant morbidity and mortality. However, the treatment options for bAVMs are severely limited, primarily relying on invasive methods that carry their own risks for intraoperative hemorrhage or even death. Currently, there are no pharmaceutical agents shown to treat this condition, primarily due to a poor understanding of bAVM pathophysiology. For the last decade, bAVM research has made significant advances, including the identification of novel genetic mutations and relevant signaling in bAVM development. However, bAVM pathophysiology is still largely unclear. Further investigation is required to understand the detailed cellular and molecular mechanisms involved, which will enable the development of safer and more effective treatment options. Endothelial cells (ECs), the cells that line the vascular lumen, are integral to the pathogenesis of bAVMs. Understanding the fundamental role of ECs in pathological conditions is crucial to unraveling bAVM pathophysiology. This review focuses on the current knowledge of bAVM-relevant signaling pathways and dysfunctions in ECs, particularly the endothelial-to-mesenchymal transition (EndMT).

Endothelial Immunosuppression in Atherosclerosis : Translational Control by Elavl1/HuR

Atherosclerotic plaques are defined by the accumulation of lipids and immune cells beneath the endothelium of the arterial intima. CD8 T cells are among the most abundant immune cell types in plaque, and conditions linked to their activation correlate with increased levels of cardiovascular disease. As lethal effectors of the immune response, CD8 T cell activation is suppressed at multiple levels. These checkpoints are critical in dampening autoimmune responses, and limiting damage in cardiovascular disease. Endothelial cells are well known for their role in recruiting CD8 T and other hematopoietic cells to low and disturbed flow (LDF) arterial regions that develop plaque, but whether they locally influence CD8 effector functions is unclear. Here, we show that endothelial cells can actively suppress CD8 T cell responses in settings of chronic plaque inflammation, but that this behavior is governed by expression of the RNA-binding protein Embryonic Lethal, Abnormal Vision-Like 1 (Elavl1). In response to immune cell recruitment in plaque, the endothelium dynamically shifts splicing of pre-mRNA and their translation to enhance expression of immune-regulatory proteins including C1q and CD27. This program is immuno-suppressive, and limited by Elavl1. We show this by Cdh5(PAC)-CreERT2-mediated deletion of Elavl1 (ECKO), and analysis of changes in translation by Translating Ribosome Affinity Purification (TRAP). In ECKO mice, the translational shift in chronic inflammation is enhanced, leading to increased ribosomal association of C1q components and other critical regulators of immune response and resulting in a ~70% reduction in plaque CD8 T cells. CITE-seq analysis of the remaining plaque T cells shows that they exhibit lower levels of markers associated with T cell receptor (TCR) signaling, survival, and activation. To understand whether the immunosuppressive mechanism occurred through failed CD8 recruitment or local modulation of T cell responses, we used a novel in vitro co-culture system to show that ECKO endothelial cells suppress CD8 T cell expansion-even in the presence of wild-type myeloid antigen-presenting cells, antigen-specific CD8 T cells, and antigen. Despite the induction of C1q mRNA by T cell co-culture in both wild-type and ECKO endothelial cells, we find C1q protein abundantly expressed only in co-culture with ECKO cells. Together, our data define a novel immune-suppressive transition in the endothelium, reminiscent of the transition of T cells to T-regs, and demonstrate the regulation of this process by Elavl1.

CAFs vs. TECs: when blood feuds fuel cancer progression, dissemination and therapeutic resistance

Neoplastic progression involves complex interactions between cancer cells and the surrounding stromal milieu, fostering microenvironments that crucially drive tumor progression and dissemination. Of these stromal constituents, cancer-associated fibroblasts (CAFs) emerge as predominant inhabitants within the tumor microenvironment (TME), actively shaping multiple facets of tumorigenesis, including cancer cell proliferation, invasiveness, and immune evasion. Notably, CAFs also orchestrate the production of pro-angiogenic factors, fueling neovascularization to sustain the metabolic demands of proliferating cancer cells. Moreover, CAFs may also directly or indirectly affect endothelial cell behavior and vascular architecture, which may impact in tumor progression and responses to anti-cancer interventions. Conversely, tumor endothelial cells (TECs) exhibit a corrupted state that has been shown to affect cancer cell growth and inflammation. Both CAFs and TECs are emerging as pivotal regulators of the TME, engaging in multifaceted biological processes that significantly impact cancer progression, dissemination, and therapeutic responses. Yet, the intricate interplay between these stromal components and the orchestrated functions of each cell type remains incompletely elucidated. In this review, we summarize the current understanding of the dynamic interrelationships between CAFs and TECs, discussing the challenges and prospects for leveraging their interactions towards therapeutic advancements in cancer.

Distinct roles of SOX9 in self-renewal of progenitors and mesenchymal transition of the endothelium

Regenerative capabilities of the endothelium rely on vessel-resident progenitors termed endothelial colony forming cells (ECFCs). This study aimed to investigate if these progenitors are impacted by conditions (i.e., obesity or atherosclerosis) characterized by increased serum levels of oxidized low-density lipoprotein (oxLDL), a known inducer of Endothelial-to-Mesenchymal Transition (EndMT). Our investigation focused on understanding the effects of EndMT on the self-renewal capabilities of progenitors and the associated molecular alterations. In the presence of oxLDL, ECFCs displayed classical features of EndMT, through reduced endothelial gene and protein expression, function as well as increased mesenchymal genes, contractility, and motility. Additionally, ECFCs displayed a dramatic loss in self-renewal capacity in the presence of oxLDL. RNA-sequencing analysis of ECFCs exposed to oxLDL validated gene expression changes suggesting EndMT and identified SOX9 as one of the highly differentially expressed genes. ATAC sequencing analysis identified SOX9 binding sites associated with regions of dynamic chromosome accessibility resulting from oxLDL exposure, further pointing to its importance. EndMT phenotype and gene expression changes induced by oxLDL in vitro or high fat diet (HFD) in vivo were reversed by the silencing of SOX9 in ECFCs or the endothelial-specific conditional knockout of Sox9 in murine models. Overall, our findings support that EndMT affects vessel-resident endothelial progenitor's self-renewal. SOX9 activation is an early transcriptional event that drives the mesenchymal transition of endothelial progenitor cells. The identification of the molecular network driving EndMT in vessel-resident endothelial progenitors presents a new avenue in understanding and preventing a range of condition where this process is involved.

MiR-29c alleviates hyperglycemia-induced inflammation via targeting TGF-β in cardiomyocytes

This study aims to investigate whether miR-29c is involved in regulating transforming growth factor-β (TGF-β) mediated inflammation in diabetic cardiomyopathy (DCM). Our data showed increased inflammation and oxidative stress in diabetic myocardium together with decrease of miR-29c and elevation of TGF-β expression. In vitro experiments, we transfected miR-29c mimic and antagomir into HL-1 cells to explore the effect of miR-29c on inflammation in hyperglycemic conditions. Overexpression of miR-29c down-regulated the elevated TNF-α level, ROS production and NADPH oxidase activity which caused by high glucose. However, above changes were reversed by miR-29c antagomir. Interestingly, TGF-β protein rather than mRNA expression was changed significantly after transfection with miR-29c mimic, indicating that the modulation of TGF-β mediated by miR-29c was at the posttranslational level. Meanwhile, we found that 3'-UTR of TGF-β was the direct target of miR-29c confirmed by dual-luciferase assay. In conclusion, our study revealed that miR-29c could alleviate hyperglycemic-induced inflammation and ROS production via targeting TGF-β in cardiomyocytes, which provides a potential target for the treatment of DCM.

Overview of multifunctional Tregs in cardiovascular disease: From insights into cellular functions to clinical implications

Regulatory T cells (Tregs) are crucial in regulating T-cell-mediated immune responses. Numerous studies have shown that dysfunction or decreased numbers of Tregs may be involved in inflammatory cardiovascular diseases (CVDs) such as atherosclerosis, hypertension, myocardial infarction, myocarditis, cardiomyopathy, valvular heart diseases, heart failure, and abdominal aortic aneurysm. Tregs can help to ameliorate CVDs by suppressing excessive inflammation through various mechanisms, including inhibition of T cells and B cells, inhibition of macrophage-induced inflammation, inhibition of dendritic cells and foam cell formation, and induction of anti-inflammatory macrophages. Enhancing or restoring the immunosuppressive activity of Tregs may thus serve as a fundamental immunotherapy to treat hypertension and CVDs. However, the precise molecular mechanisms underlying the Tregs-induced protection against hypertension and CVDs remain to be investigated. This review focuses on recent advances in our understanding of Tregs subsets and function in CVDs. In addition, we discuss promising strategies for using Tregs through various pharmacological approaches to treat hypertension and CVDs.

Cracking the code of the cardiovascular enigma: hPSC-derived endothelial cells unveil the secrets of endothelial dysfunction

Endothelial dysfunction is a central contributor to the development of most cardiovascular diseases and is characterised by the reduced synthesis or bioavailability of the vasodilator nitric oxide together with other abnormalities such as inflammation, senescence, and oxidative stress. The use of patient-specific and genome-edited human pluripotent stem cell-derived endothelial cells (hPSC-ECs) has shed novel insights into the role of endothelial dysfunction in cardiovascular diseases with strong genetic components such as genetic cardiomyopathies and pulmonary arterial hypertension. However, their utility in studying complex multifactorial diseases such as atherosclerosis, metabolic syndrome and heart failure poses notable challenges. In this review, we provide an overview of the different methods used to generate and characterise hPSC-ECs before comprehensively assessing their effectiveness in cardiovascular disease modelling and high-throughput drug screening. Furthermore, we explore current obstacles that will need to be overcome to unleash the full potential of hPSC-ECs in facilitating patient-specific precision medicine. Addressing these challenges holds great promise in advancing our understanding of intricate cardiovascular diseases and in tailoring personalised therapeutic strategies.

An Integrative Transcriptome Subtraction Strategy to Identify Human lncRNAs That Specifically Play a Role in Activation of Human Hepatic Stellate Cells

Fibrotic liver features excessive deposition of extracellular matrix (ECM), primarily produced from "activated" hepatic stellate cells (HSCs). While targeting human HSCs (hHSCs) in fibrosis therapeutics shows promise, the overall understanding of hHSC activation remains limited, in part because it is very challenging to define the role of human long non-coding RNAs (lncRNAs) in hHSC activation. To address this challenge, we identified another cell type that acts via a diverse gene network to promote fibrogenesis. Then, we identified the lncRNAs that were differentially regulated in activated hHSCs and the other profibrotic cell. Next, we conducted concurrent analysis to identify those lncRNAs that were specifically involved in fibrogenesis. We tested and confirmed that transdifferentiation of vascular smooth muscle cells (VSMCs) represents such a process. By overlapping TGFβ-regulated lncRNAs in multiple sets of hHSCs and VSMCs, we identified a highly selected list of lncRNA candidates that could specifically play a role in hHSC activation. We experimentally characterized one human lncRNA, named CARMN, which was significantly regulated by TGFβ in all conditions above. CARMN knockdown significantly reduced the expression levels of a panel of marker genes for hHSC activation, as well as the levels of ECM deposition and hHSC migration. Conversely, gain of function of CARMN using CRISPR activation (CRISPR-a) yielded the completely opposite effects. Taken together, our work addresses a bottleneck in identifying human lncRNAs that specifically play a role in hHSC activation and provides a framework to effectively select human lncRNAs with significant pathophysiological role.

Intrinsic Gata4 expression sensitizes the aortic root to dilation in a Loeys-Dietz syndrome mouse model

Loeys-Dietz syndrome (LDS) is an aneurysm disorder caused by mutations that decrease transforming growth factor-β (TGF-β) signaling. Although aneurysms develop throughout the arterial tree, the aortic root is a site of heightened risk. To identify molecular determinants of this vulnerability, we investigated the heterogeneity of vascular smooth muscle cells (VSMCs) in the aorta of Tgfbr1 M318R/+ LDS mice by single cell and spatial transcriptomics. Reduced expression of components of the extracellular matrix-receptor apparatus and upregulation of stress and inflammatory pathways were observed in all LDS VSMCs. However, regardless of genotype, a subset of Gata4-expressing VSMCs predominantly located in the aortic root intrinsically displayed a less differentiated, proinflammatory profile. A similar population was also identified among aortic VSMCs in a human scRNAseq dataset. Postnatal VSMC-specific Gata4 deletion reduced aortic root dilation in LDS mice, suggesting that this factor sensitizes the aortic root to the effects of impaired TGF-β signaling.

Network-based prioritization and validation of regulators of vascular smooth muscle cell proliferation in disease

Aberrant vascular smooth muscle cell (VSMC) homeostasis and proliferation characterize vascular diseases causing heart attack and stroke. Here we elucidate molecular determinants governing VSMC proliferation by reconstructing gene regulatory networks from single-cell transcriptomics and epigenetic profiling. We detect widespread activation of enhancers at disease-relevant loci in proliferation-predisposed VSMCs. We compared gene regulatory network rewiring between injury-responsive and nonresponsive VSMCs, which suggested shared transcription factors but differing target loci between VSMC states. Through in silico perturbation analysis, we identified and prioritized previously unrecognized regulators of proliferation, including RUNX1 and TIMP1. Moreover, we showed that the pioneer transcription factor RUNX1 increased VSMC responsiveness and that TIMP1 feeds back to promote VSMC proliferation through CD74-mediated STAT3 signaling. Both RUNX1 and the TIMP1-CD74 axis were expressed in human VSMCs, showing low levels in normal arteries and increased expression in disease, suggesting clinical relevance and potential as vascular disease targets.

UHRF1 inhibition mitigates vascular endothelial cell injury and ameliorates atherosclerosis in mice via regulating the SMAD7/YAP1 axis

BACKGROUND

Endothelial cell injury and dysfunction lead to cholesterol and lipid accumulation and atherosclerotic plaque formation in the arterial wall during atherosclerosis (AS) progression, Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1), a DNA methylation regulator, was strongly upregulated in atherosclerotic plaque lesions in mice. This study aimed to investigate the precise biological functions and regulatory mechanisms of UHRF1 on endothelial dysfunction during AS development.

METHODS

UHRF1 levels in the atherosclerotic plaque tissues and normal arterial intima from AS patients were tested with Western blot analysis and immunohistochemistry assays. Human umbilical vein endothelial cells (HUVECs) were stimulated with oxidized low-density lipoprotein (ox-LDL) to induce an injury model and then transfected with short hairpin RNA targeting UHRF1 (sh-UHRF1). Cell proliferation, migration, apoptosis, the levels of inflammatory cytokines including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and the protein levels adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were measured. Moreover, co-immunoprecipitation assay was used to determine the interactions between UHRF1 and DNA methyltransferases 1 (DNMT1), As well as mothers against DPP homolog 7 (SMAD7) and yes-associated protein 1 (YAP1). SMAD7 promoter methylation was examined with methylation-specific PCR. In addition, we established an AS mouse model to determine the in vivo effects of UHRF1 on AS progression.

RESULTS

UHRF1 was upregulated in atherosclerotic plaque tissues and ox-LDL-treated HUVECs. UHRF1 knockdown mitigated ox-LDL-induced proliferation and migration inhibition, apoptosis and the production of TNF-α, IL-6, VCAM-1, and ICAM-1 in HUVECs. Mechanistically, UHRF1 promoted DNMT1-mediated SMAD7 promoter methylation and inhibited its expression. SMAD7 knockdown abolished the protective effects of UHRF1 knockdown on ox-LDL-induced HUVEC injury. Moreover, SMAD7 interacted with YAP1 and inhibited YAP1 expression by promoting YAP1 protein ubiquitination-independent degradation in HUVECs. YAP1 overexpression abrogated SMAD7 overexpression-mediated protective effects on ox-LDL-induced HUVEC injury. Finally, UHRF1 knockdown alleviated atherosclerotic plaque deposition and arterial lesions in AS mice.

CONCLUSION

UHRF1 inhibition mitigates vascular endothelial cell injury and ameliorates AS progression in mice by regulating the SMAD7/YAP1 axis.

Atherosclerotic Plaque Epigenetic Age Acceleration Predicts a Poor Prognosis and Is Associated With Endothelial-to-Mesenchymal Transition in Humans

BACKGROUND

Epigenetic age estimators (clocks) are predictive of human mortality risk. However, it is not yet known whether the epigenetic age of atherosclerotic plaques is predictive for the risk of cardiovascular events.

METHODS

Whole-genome DNA methylation of human carotid atherosclerotic plaques (n=485) and of blood (n=93) from the Athero-Express endarterectomy cohort was used to calculate epigenetic age acceleration (EAA). EAA was linked to clinical characteristics, plaque histology, and future cardiovascular events (n=136). We studied whole-genome DNA methylation and bulk and single-cell transcriptomics to uncover molecular mechanisms of plaque EAA. We experimentally confirmed our in silico findings using in vitro experiments in primary human coronary endothelial cells.

RESULTS

Male and female patients with severe atherosclerosis had a median chronological age of 69 years. The median epigenetic age was 65 years in females (median EAA, -2.2 [interquartile range, -4.3 to 2.2] years) and 68 years in males (median EAA, -0.3 [interquartile range, -2.9 to 3.8] years). Patients with diabetes and a high body mass index had higher plaque EAA. Increased EAA of plaque predicted future events in a 3-year follow-up in a Cox regression model (univariate hazard ratio, 1.7; P=0.0034) and adjusted multivariate model (hazard ratio, 1.56; P=0.02). Plaque EAA predicted outcome independent of blood EAA (hazard ratio, 1.3; P=0.018) and of plaque hemorrhage (hazard ratio, 1.7; P=0.02). Single-cell RNA sequencing in plaque samples from 46 patients in the same cohort revealed smooth muscle and endothelial cells as important cell types in plaque EAA. Endothelial-to-mesenchymal transition was associated with EAA, which was experimentally confirmed by TGFβ-triggered endothelial-to-mesenchymal transition inducing rapid epigenetic aging in coronary endothelial cells.

CONCLUSIONS

Plaque EAA is a strong and independent marker of poor outcome in patients with severe atherosclerosis. Plaque EAA was linked to mesenchymal endothelial and smooth muscle cells. Endothelial-to-mesenchymal transition was associated with EAA, which was experimentally validated. Epigenetic aging mechanisms may provide new targets for treatments that reduce atherosclerosis complications.

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

SMAD3 rs17228212 Polymorphism Is Associated with Advanced Carotid Atherosclerosis in a Slovenian Population

Smad proteins influence the TGFβ signaling pathway, which plays an important role in the progression of atherosclerosis. The aim of our study was to investigate the association between the rs17228212 polymorphism of the SMAD3 gene and advanced carotid atherosclerosis in Slovenian subjects and to investigate the effect of the rs17228212 SMAD3 polymorphism on the expression of SMAD3 in endarterectomy sequesters. In this cross-sectional case-control study, 881 unrelated Caucasians were divided into two groups. The first group included 308 patients with advanced carotid atherosclerosis of the common or internal carotid artery with stenosis greater than 75% that underwent a revascularization procedure (cases). The control group consisted of 573 subjects without hemodynamically significant carotid atherosclerosis. We analyzed the rs17228212 polymorphism of the SMAD3 gene using the StepOne real-time polymerase chain reaction system and TaqMan SNP genotyping assay. The results in the two genetic models showed a statistically significant association, codominant (OR 4.05; CI 1.10-17.75; p = 0.037) and dominant (OR 3.60; CI 1.15-15.45; p = 0.045). An immunohistochemical analysis of SMAD3 expression was conducted for 26 endarterectomy specimens. The T allele of the rs17228212 SMAD3 gene was shown to be associated with an increased numerical area density of SMAD3-positive cells in carotid plaques.

H3K27Me3 abundance increases fibrogenesis during endothelial-to-mesenchymal transition via the silencing of microRNA-29c

Objective

Endothelial-to-mesenchymal transition (EndMT) is a transdifferentiation process in which endothelial cells (ECs) adopt a mesenchymal-like phenotype. Over the past few years, it became clear that EndMT can contribute to several cardiovascular pathologies. However, the molecular pathways underlying the development of EndMT remain incompletely understood. Since the epigenetic enzyme Enhancer of Zeste Homolog 2 (EZH2) and its concomitant mark H3K27Me3 have been shown to be elevated in many cardiovascular diseases that associate with EndMT, we hypothesized that H3K27Me3 is a determinant for the susceptibility of EndMT.

Methods

To study the association between H3K27Me3 and EndMT, a knockdown model of EZH2 in human endothelial cells (HUVEC) was utilized to reduce H3K27Me3 abundance, followed by induction of EndMT using TGFβ1. The expression of molecular markers of EndMT and fibrogenesis were analysed.

Results

In cultured HUVECs, a reduction of H3K27Me3 abundance facilitates EndMT but mitigates fibrogenesis as shown by a decreased expression of collagen I and III. In HUVEC, H3K27Me3 abundance directly affects the expression of miR29c, a collagen-targeting miRNA. Additionally, knockdown of miR-29c in HUVEC with low H3K27Me3 abundance partly restored the expression of collagen I and III. Expectedly, in rats with perivascular fibrosis an increased abundance of H3K27Me3 associated with a decreased expression of miR-29c.

Conclusion

our data shows that endothelial fibrogenesis underlies an epigenetic regulatory pathway and we demonstrate that a decreased abundance of H3K27Me3 in ECs blunts fibrogenesis in part in a miR-29c dependent manner. Therefore, a reduction of H3K27Me3 could serve as a novel therapeutical strategy to mitigate fibrogenesis and may prove to be beneficial in fibrogenic diseases including atherosclerosis, cardiac fibrosis, and PAH.

Removal of endothelial surface-associated von villebrand factor suppresses accelerate datherosclerosis after myocardial infarction

BACKGROUND

Thromboinflammation involving platelet adhesion to endothelial surface-associated von Willebrand factor (VWF) has been implicated in the accelerated progression of non-culprit plaques after MI. The aim of this study was to use arterial endothelial molecular imaging to mechanistically evaluate endothelial-associated VWF as a therapeutic target for reducing remote plaque activation after myocardial infarction (MI).

METHODS

Hyperlipidemic mice deficient for the low-density lipoprotein receptor and Apobec-1 underwent closed-chest MI and were treated chronically with either: (i) recombinant ADAMTS13 which is responsible for proteolytic removal of VWF from the endothelial surface, (ii) N-acetylcysteine (NAC) which removes VWF by disulfide bond reduction, (iii) function-blocking anti-factor XI (FXI) antibody, or (iv) no therapy. Non-ischemic controls were also studied. At day 3 and 21, ultrasound molecular imaging was performed with probes targeted to endothelial-associated VWF A1-domain, platelet GPIbα, P-selectin and vascular cell adhesion molecule-1 (VCAM-1) at lesion-prone sites of the aorta. Histology was performed at day 21.

RESULTS

Aortic signal for P-selectin, VCAM-1, VWF, and platelet-GPIbα were all increased several-fold (p < 0.01) in post-MI mice versus sham-treated animals at day 3 and 21. Treatment with NAC and ADAMTS13 significantly attenuated the post-MI increase for all four molecular targets by > 50% (p < 0.05 vs. non-treated at day 3 and 21). On aortic root histology, mice undergoing MI versus controls had 2-4 fold greater plaque size and macrophage content (p < 0.05), approximately 20-fold greater platelet adhesion (p < 0.05), and increased staining for markers of platelet transforming growth factor-β1 signaling. Accelerated plaque growth and inflammatory activation was almost entirely prevented by ADAMTS13 and NAC. Inhibition of FXI had no significant effect on molecular imaging signal or plaque morphology.

CONCLUSIONS

Plaque inflammatory activation in remote arteries after MI is strongly influenced by VWF-mediated platelet adhesion to the endothelium. These findings support investigation into new secondary preventive therapies for reducing non-culprit artery events after MI.

The Vascular Function of Resistance Arteries Depends on NADPH Oxidase 4 and Is Exacerbated by Perivascular Adipose Tissue

The NADPH oxidase NOX4 that releases H2O2 can mediate vasoprotective mechanisms under pathophysiological conditions in conductive arteries. However, the role of NOX4 in resistance arteries and in perivascular adipose tissue is not well understood. We hypothesized that NOX4 is of functional importance in resistance arteries and perivascular adipose tissue under dyslipidemia conditions. We detected elevated NOX4 expression in murine and human vessels under dyslipidemia. Diminishing Nox4 under these conditions led to endothelial dysfunction in resistance arteries. The mesenteric arteries of Nox4-/-/Ldlr-/- mice revealed decreased eNos mRNA expression. Inhibition of eNOS in those vessels did not affect vascular function, while in Ldlr-/- mice endothelial function was significantly altered. Anticontractile properties of perivascular adipose tissue at resistance arteries were diminished in Nox4-/-/Ldlr-/- compared with Ldlr-/- mice. In addition, the presence of perivascular adipose tissue further worsened endothelial dysfunction in mesenteric arteries under dyslipidemia conditions. Perivascular adipose tissue from mesenteric arteries revealed a higher expression of markers of white adipocytes compared to markers of beige/brown adipocytes. Among those white adipocyte markers, leptin was significantly less expressed in perivascular adipose tissue from Nox4-/-/Ldlr-/- mice compared with Ldlr-/- mice. Furthermore, in human perivascular adipose tissue with a profound pattern of white adipocyte marker genes, we detected a correlation of NOX4 and LEP expression. In addition, incubating arterial vessels with leptin induced nitrite release, indicating increased eNOS activity. In humans, a higher expression of leptin in perivascular adipose tissue correlated with eNOS expression in the corresponding left internal mammary artery. In conclusion, vascular function of resistance arteries was dependent on Nox4-derived H2O2, especially under dyslipidemia conditions. Perivascular adipose tissue of the mesenteric arteries with white adipose tissue characteristics further aggravated endothelial function through reduced leptin-eNOS signaling.

Identification and characterization of extrachromosomal circular DNA in large-artery atherosclerotic stroke

Extrachromosomal circular DNA (eccDNA) is a new biomarker and regulator of diseases. However, the role of eccDNAs in large-artery atherosclerotic (LAA) stroke remains unclear. Through high-throughput circle-sequencing technique, the length distribution, genomic characteristic and motifs feature of plasma eccDNA from healthy controls (CON) and patients with LAA stroke were analysed. Then, the potential functions of the annotated eccDNAs were investigated using GO and KEGG pathway analyses. EccDNAs mapped to the reference genome showed SHN3 and BCL6 were LAA stroke unique transcription factors. The genes of differentially expressed eccDNAs between LAA stroke patients and CON were mainly involved in axon/dendrite/neuron projection development and maintenance of cellular structure via Wnt, Rap1 and MAPK pathways. Moreover, LAA stroke unique eccDNA genes played a role in regulation of coagulation and fibrinolysis, and there were five LAA stroke unique eccDNAs (Chr2:12724406-12724784, Chr4:1867120-186272046, Chr4:186271494-186271696, Chr7:116560296-116560685 and Chr11:57611780-5761192). Additionally, POLR2C and AURKA carried by ecDNAs (eccDNA size >100 kb) of LAA stroke patients were significantly associated with development of LAA stroke. Our data firstly revealed the characteristics of eccDNA in LAA stroke and the functions of LAA stroke unique eccDNAs and eccDNA genes, suggesting eccDNA is a novel biomarker and mechanism of LAA stroke.