The role of smooth muscle cells in plaque stability: Therapeutic targeting potential

Epigenetic Modulation of Vascular Smooth Muscle Cell Phenotype Switching in Early-Onset Acute Myocardial Infarction

BACKGROUND

The epigenetic mechanisms underlying early-onset acute myocardial infarction (AMI) remain insufficiently characterized. The present study aims to elucidate the pathophysiology of early-onset AMI by investigating its epigenetic features as molecular indicators.

METHODS

A comparative differential methylation analysis was performed on whole blood samples from 298 patients with early-onset AMI with clinical follow-up and 247 controls using targeted bisulfite sequencing. Clusters of differentially methylated sites (CDMSs) were defined to highlight regions of concentrated methylation changes in patients with early-onset AMI. Cox proportional hazards regression was conducted to evaluate the prognostic significance of the methylation biomarkers.

RESULTS

A total of 692 differentially methylated sites (DMSs) were identified as biomarkers associated with early-onset AMI. Among these, 396 DMSs were grouped into 147 CDMSs. Notably, the UHRF1 and STIMATE genes, which regulate synthetic and osteoblast-like vascular smooth muscle cell phenotypes, respectively, contained CDMSs with the highest number of significant DMSs. UHRF1 demonstrated a CDMS with 10 significant DMSs within a 117-bp region, while STIMATE included a 264-bp CDMS with 10 significant DMSs. Both regions also exhibited consistent methylation patterns in coronary tissues, comparing human coronary plaque to normal coronary artery samples. Additionally, the HIPK3 gene, which modulates STAT3 (signal transducer and activator of transcription 3) expression, thereby promoting osteoblast-like transformation in vascular smooth muscle cells, showed a CDMS with 5 significant DMSs within a 123-bp region, with further validation in the corresponding tissues. Furthermore, over 66% biomarkers demonstrated significant associations with mortality in patients with early-onset AMI, providing evidence of the impact of these biomarkers on the pathophysiology of the disease.

CONCLUSIONS

This innovative epigenomic study into early-onset AMI not only identifies biomarkers associated with the disease and its mortality but also highlights the critical role of vascular smooth muscle cell phenotype regulation in early-onset AMI pathogenesis. Our findings suggest that changes in vascular smooth muscle cell phenotypes toward synthetic and osteoblast-like states play a crucial role in early-onset AMI.

Ultrasound-Driven Piezoelectric Heterostructures Block Early Atherosclerotic Plaques Progression

Atherosclerosis (AS), marked by lipid buildup and chronic inflammation in arteries, leads to major cardiovascular events. Macrophages contribute to AS by engulfing low-density lipoproteins, forming foam cells, and driving inflammation that promotes plaque growth and instability. The emerging piezocatalytic therapy uses piezoelectric materials to generate radicals that target inflammation-related macrophages for AS treatment, but the conventional materials suffer from low radical yield, substantially limiting clinical use. In this study, the construction of piezoelectric BaTiO3/Ta4C3 MXene heterostructured nanosheets (BTOMX NSs) is reported for achieving enhanced piezoelectric AS treatment by blocking early atherosclerotic plaque progression. The composite BTOMX NSs feature high electron-hole separation efficiency due to their narrowed bandgap and high surface potential under ultrasound irradiation, enabling more effective radical generation by piezocatalytic effects. Especially, these biocompatible piezoelectric nanosheets accumulate in plaques and are efficiently internalized by macrophages, where they generate radicals under ultrasound stimulation, ultimately triggering macrophage apoptosis and interrupting plaque progression. In ApoE-/- mice, the BTOMX NSs remove lesional macrophages, reduce lipid accumulation, and mitigate inflammation, decreasing plaque burden from 21.42% to 9.04%. Taken together, this work provides a paradigm for enhancing BaTiO3-based piezocatalytic performance by heterostructure construction, demonstrating an efficient, noninvasive, and safe therapeutic approach for treating early-stage AS.

Protocatechuic Acid Attenuates Inflammation in Macrophage-like Vascular Smooth Muscle Cells in ApoE-/- Mice

Background/Objectives: Non-resolving inflammation in macrophage-like cells (MLCs) transdifferentiated from vascular smooth muscle cells and monocyte-derived macrophages aggravates atherosclerosis. We previously showed that polyphenolic protocatechuic acid (PCA) could reduce inflammation burden in monocyte-derived macrophages; however, it remains unknown how this compound affects MLCs inflammation. Methods: MLCs from the transdifferentiation of vascular smooth muscle cells induced by cholesterol and 30-week-old male ApoE-/- mice fed a semi-purified AIN-93G diet containing either 0.003% (wt:wt) of PCA for a duration of 20 weeks were used to examine the impact of PCA on the inflammatory response of MLCs. Results: Physiologically achievable doses of PCA (0.25-1 μM) dose-dependently inhibited lipopolysaccharide-induced NF-κB activation and simultaneously reduced pro-inflammatory cytokine levels. Mechanistically, this effect was mediated by effecting exportin-1 function, promoting nuclear export of phosphorylated-p65, independent of NF-κB kinase inhibitor α/β/γ, NF-κB inhibitor α, or importin-mediated nuclear import of p-p65. PCA reduced the nucleocytoplasmic ratio of exportin-1 (44%) without altering its abundance. Importantly, dietary supplementation with PCA reduced interleukin-1β content within MLCs in atherosclerotic plaques of ApoE-/- mice. In addition, dietary PCA reduced MLCs content in atherosclerotic plaques. Conclusions: PCA could attenuate inflammatory response in MLCs by targeting exportin-1 and also could inhibit the transdifferentiation of vascular smooth muscle cells into MLCs within atherosclerotic plaques, which might promote the translation from preclinical studies to clinical trials in patients with atherosclerosis.

An intimal-lumen model in a microfluidic device: potential platform for atherosclerosis-related studies

Atherosclerosis is a chronic inflammatory vascular disorder driven by factors such as endothelial dysfunction, hypertension, hyperlipidemia, and arterial calcification, and is considered a leading global cause of death. Existing atherosclerosis models have limitations due to the absence of an appropriate hemodynamic microenvironment in vitro and interspecies differences in vivo. Here, we develop a simple but robust microfluidic intimal-lumen model of early atherosclerosis using interconnected dual channels for studying monocyte transmigration and foam cell formation at an arterial shear rate. To the best of our knowledge, this is the first study that creates a physiologically relevant microenvironment under an arterial shear rate to modulate lipid-laden foam cells on a microfluidic platform. As a proof of concept, we use murine endothelial cells to develop a vascular lumen in one channel and collagen-embedded murine smooth muscle cells to mimic the subendothelial intimal layer in another channel. The model successfully triggers endothelial dysfunction upon TNF-α stimulation, initiating monocyte adhesion to the endothelial monolayer under the arterial shear rate. Unlike existing in vitro models, native low-density lipoprotein (LDL) is added in the culture media instead of ox-LDL to stimulate subendothelial lipid accumulation, thereby mimicking more accurate physiology. The subendothelial transmigration of adherent monocytes and subsequent foam cell formation is also achieved under flow conditions in the model. The model also investigates the inhibitory effect of aspirin in monocyte adhesion and transmigration. The model exhibits a significant dose-dependent reduction in monocyte adhesion and transmigration upon aspirin treatment, making it an excellent tool for drug testing.

Inflammatory Pathways in Coronary Artery Disease: Which Ones to Target for Secondary Prevention?

Coronary artery disease (CAD), the build-up of atherosclerotic plaques on the wall of blood vessels, causes adverse cardiovascular events. Secondary prevention focuses on treating patients with existing plaques to prevent disease progression. Recent studies have shown that inflammation is an independent risk factor that drives disease progression, and targeting inflammation could be an effective therapeutic strategy for secondary prevention. In this review, we highlighted the roles of several inflammatory pathways in rupture and erosion, two major processes through which established plaques lead to adverse cardiovascular events. In the past 15 years, numerous clinical trials have tested the therapeutic potential of targeting these pathways, including neutralizing inflammatory cytokines and blocking signaling transduction of the inflammatory pathways. Only colchicine was approved for clinical use in patients with CAD. This is primarily due to the multifaceted roles of inflammatory pathways in disease progression. Commonly used pre-clinical models provided robust information for the onset of early disease but limited understanding of the inflammatory network in established plaques. This review will summarize lessons learned from successful and failed clinical trials to advocate for assessing inflammation in established plaques before designing therapeutics for secondary prevention.

Mechanisms of inflammatory microenvironment formation in cardiometabolic diseases: molecular and cellular perspectives

Cardiometabolic diseases (CMD) are leading causes of death and disability worldwide, with complex pathophysiological mechanisms in which inflammation plays a crucial role. This review aims to elucidate the molecular and cellular mechanisms within the inflammatory microenvironment of atherosclerosis, hypertension and diabetic cardiomyopathy. In atherosclerosis, oxidized low-density lipoprotein (ox-LDL) and pro-inflammatory cytokines such as Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-α) activate immune cells contributing to foam cell formation and arterial wall thickening. Hypertension involves the activation of the renin-angiotensin system (RAS) alongside oxidative stress-induced endothelial dysfunction and local inflammation mediated by T cells. In diabetic cardiomyopathy, a high-glucose environment leads to the accumulation of advanced glycation end products (AGEs), activating the Receptor for Advanced Glycation Endproducts (RAGE) and triggering inflammatory responses that further damage cardiac and microvascular function. In summary, the inflammatory mechanisms in different types of metabolic cardiovascular diseases are complex and diverse; understanding these mechanisms deeply will aid in developing more effective individualized treatment strategies.

Spatial lipidomic profiles of atherosclerotic plaques: A mass spectrometry imaging study

Lipids contribute to atherosclerotic cardiovascular disease but their roles are not fully understood. Spatial lipid composition of atherosclerotic plaques was compared between species focusing on aortic plaques from New Zealand White rabbits and carotid plaques from humans (n = 3), using matrix-assisted laser desorption/ionization mass spectrometry imaging. Histologically discriminant lipids within plaque features (neointima and media in rabbits, and lipid-necrotic core and fibrous cap/tissue in humans) included sphingomyelins, phosphatidylcholines, and cholesteryl esters. There were 67 differential lipids between rabbit plaque features and 199 differential lipids in human, each with variable importance in projection score ≥1.0 and p < 0.05. The lipid profile of plaques in the rabbit model closely mimicked that of human plaques and two key pathways (impact value ≥ 0.1), sphingolipid and glycerophospholipid metabolism, were disrupted by atherosclerosis in both species. Thus, mass spectrometry imaging of spatial biomarkers offers valuable insights into atherosclerosis.

β-Hydroxybutyrate Alleviates Atherosclerotic Calcification by Inhibiting Endoplasmic Reticulum Stress-Mediated Apoptosis via AMPK/Nrf2 Pathway

BACKGROUND

Atherosclerotic calcification (AC) is a common feature of atherosclerotic cardiovascular disease. β-Hydroxybutyrate (BHB) has been identified as a molecule that influences cardiovascular disease. However, whether BHB can influence AC is still unknown.

METHODS AND RESULTS

In this study, ApoE-/- mice, fed a Western diet, were used to examine the effects of BHB on AC. Rat vascular smooth muscle cells (VSMCs) were used to verify the impacts of BHB on AC and to explore the underlying mechanisms. The results show that Western diet-challenged ApoE-/- mice, supplemented with BHB for 24 weeks, exhibited reduced calcified areas, calcium content, and alkaline phosphatase (ALP) activity in the aortas, as well as ameliorated severity of AC. Furthermore, BHB downregulated the expression of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP), thereby reducing endoplasmic reticulum stress (ERS) and ERS-mediated apoptosis in the aortas of the mice. Consistently, in vitro studies showed that BHB reduced ALP activity and calcium content in VSMCs, and inhibited VSMC calcification. Additionally, BHB suppressed ERS-mediated apoptosis in VSMCs.

CONCLUSIONS

In summary, the present results demonstrate that BHB can alleviate atherosclerotic calcification by inhibiting ERS-mediated apoptosis. Therefore, BHB may serve as a viable therapeutic agent for AC.

Vascular Extracellular Matrix in Atherosclerosis

The extracellular matrix (ECM) plays a central role in the structural integrity and functionality of the cardiovascular system. Moreover, the ECM is involved in atherosclerotic plaque formation and stability. In fact, ECM remodeling affects plaque stability, cellular migration, and inflammatory responses. Collagens, fibronectin, laminin, elastin, and proteoglycans are crucial proteins during atherosclerosis development. This dynamic remodeling is driven by proteolytic enzymes such as matrix metalloproteinases (MMPs), cathepsins, and serine proteases. Exploring and investigating ECM dynamics is an important step to designing innovative therapeutic strategies targeting ECM remodeling mechanisms, thus offering significant advantages in the management of cardiovascular diseases. This review illustrates the structure and role of vascular ECM, presenting a new perspective on ECM remodeling and its potential as a therapeutic target in atherosclerosis treatments.

Spatial Transcriptomic Approach to Understanding Coronary Atherosclerotic Plaque Stability

BACKGROUND

Coronary atherosclerotic plaques susceptible to acute coronary syndrome have traditionally been characterized by their surrounding cellular architecture. However, with the advent of intravascular imaging, novel mechanisms of coronary thrombosis have emerged, challenging our contemporary understanding of acute coronary syndrome. These intriguing findings underscore the necessity for a precise molecular definition of plaque stability. Considering this, our study aimed to investigate the vascular microenvironment in patients with stable and unstable plaques using spatial transcriptomics.

METHODS

Autopsy-derived coronary arteries were preserved and categorized by plaque stability (n=5 patients per group). We utilized the GeoMx spatial profiling platform and Whole Transcriptome Atlas to link crucial histological morphology markers in coronary lesions with differential gene expression in specific regions of interest, thereby mapping the vascular transcriptome. This innovative approach allowed us to conduct cell morphological and spatially resolved transcriptional profiling of atherosclerotic plaques while preserving crucial intercellular signaling.

RESULTS

We observed intriguing spatial and cell-specific transcriptional patterns in stable and unstable atherosclerotic plaques, showcasing regional variations within the intima and media. These regions exhibited differential expression of proinflammatory molecules (eg, IFN-γ [interferon-γ], MHC [major histocompatibility complex] class II, proinflammatory cytokines) and prothrombotic signaling pathways. By using lineage tracing through spatial deconvolution of intimal CD68+ (cluster of differentiation 68) cells, we characterized unique, intraplaque subpopulations originating from endothelial, smooth muscle, and myeloid lineages with distinct regional locations associated with plaque instability. In addition, unique transcriptional signatures were observed in vascular smooth muscle and CD68+ cells among plaques exhibiting coronary calcification.

CONCLUSIONS

Our study illuminates distinct cell-specific and regional transcriptional alterations present in unstable plaques. Furthermore, we characterize spatially resolved, in situ evidence supporting cellular transdifferentiation and intraplaque plasticity as significant contributors to plaque instability in human coronary atherosclerosis. Our results provide a powerful resource for the identification of novel mediators of acute coronary syndrome, opening new avenues for preventative and therapeutic treatments.

Why Current Detection of Vascular Calcification Falls Short and How to Improve on It

Vascular calcification is a common phenomenon in various vascular diseases, where its presence heralds increased occurrence of adverse disease events, which invariably lead to increased morbidity and mortality in patients. Although the impact of calcification has become apparent, adequate and early detection of the most damaging form of early microcalcification is still in its infancy, preventing reliable identification of locations that would benefit from intervention. In this review, we will provide an overview of the current state-of-the-art noninvasive calcification imaging and its persisting limitations. We discuss promising approaches that may address these limitations in the future. In this context particular attention will be paid to imaging modalities such as CT, PET, and ultrasonography and molecular and cellular mechanisms and agents involved in physiological bone formation.

Update on cardiac imaging: A critical analysis

Imaging is instrumental in diagnosing and directing the management of atherosclerosis. In 1958 the first diagnostic coronary angiography (CA) was performed, and since then further development has led to new methods such as coronary CT angiography (CTA), optical coherence tomography (OCT), positron tomography (PET), and intravascular ultrasound (IVUS). Currently, CA remains powerful for visualizing coronary arteries; however, recent studies show the benefits of using other non-invasive techniques. This review identifies optimum imaging techniques for diagnosing and monitoring plaque stability. This becomes even direr now, given the rapidly rising incidence of atherosclerosis in society today. Many acute coronary events, including acute myocardial infarctions and sudden deaths, are attributable to plaque rupture. Although fatal, these events can be preventable. We discuss the factors affecting plaque integrity, such as increased inflammation, medications like statins, and increased lipid content. Some of these precipitating factors are identifiable through imaging. However, we also highlight significant complications arising in some modalities; in CA this can include ventricular arrhythmia and even death. Extending this, we elucidated from the literature that risk can also vary based on the location of arteries and their plaques. Promisingly, there are less invasive methods being trialled for assessing plaque stability, such as Cardiac Magnetic Resonance Imaging (CMR), which is already in use for other cardiac diseases like cardiomyopathies. Therefore, future research focusing on using imaging modalities in conjunction may be sensible, to bridge between the effectiveness of modalities, at the expense of increased complications, and vice versa.

Implications and hidden toxicity of cardiometabolic syndrome and early-stage heart failure in carfilzomib-induced cardiotoxicity

BACKGROUND AND PURPOSE

Cancer therapy-related cardiovascular adverse events (CAEs) in presence of comorbidities, are in the spotlight of the cardio-oncology guidelines. Carfilzomib (Cfz), indicated for relapsed/refractory multiple myeloma (MM), presents with serious CAEs. MM is often accompanied with co-existing comorbidities. However, Cfz use in MM patients with cardiometabolic syndrome (CMS) or in heart failure with reduced ejection fraction (HFrEF), is questionable.

EXPERIMENTAL APPROACH

ApoE-/- and C57BL6/J male mice received 14 weeks Western Diet (WD) (CMS models). C57BL6/J male mice underwent permanent LAD ligation for 14 days (early-stage HFrEF model). CMS- and HFrEF-burdened mice received Cfz for two consecutive or six alternate days. Daily metformin and atorvastatin administrations were performed additionally to Cfz, as prophylactic interventions. Mice underwent echocardiography, while proteasome activity, biochemical and molecular analyses were conducted.

KEY RESULTS

CMS did not exacerbate Cfz left ventricular (LV) dysfunction, whereas Cfz led to metabolic complications in both CMS models. Cfz induced autophagy and Ca2+ homeostasis dysregulation, whereas metformin and atorvastatin prevented Cfz-mediated LV dysfunction and molecular deficits in the CMS-burdened myocardium. Early-stage HFrEF led to depressed LV function and increased protein phosphatase 2A (PP2A) activity. Cfz further increased myocardial PP2A activity, inflammation and Ca2+-cycling dysregulation. Metformin co-administration exerted an anti-inflammatory potential on the myocardium without improving LV function.

CONCLUSION AND IMPLICATIONS

CMS and HFrEF seem to exacerbate Cfz-induced CAEs, by presenting metabolism-related hidden toxicity and PP2A-related cardiac inflammation, respectively. Metformin retains its prophylactic potential in the presence of CMS, while mitigating inflammation and Ca2+ signalling dysregulation in the HFrEF myocardium.

Integrating Computational and Biological Hemodynamic Approaches to Improve Modeling of Atherosclerotic Arteries

Atherosclerosis is the primary cause of cardiovascular disease, resulting in mortality, elevated healthcare costs, diminished productivity, and reduced quality of life for individuals and their communities. This is exacerbated by the limited understanding of its underlying causes and limitations in current therapeutic interventions, highlighting the need for sophisticated models of atherosclerosis. This review critically evaluates the computational and biological models of atherosclerosis, focusing on the study of hemodynamics in atherosclerotic coronary arteries. Computational models account for the geometrical complexities and hemodynamics of the blood vessels and stenoses, but they fail to capture the complex biological processes involved in atherosclerosis. Different in vitro and in vivo biological models can capture aspects of the biological complexity of healthy and stenosed vessels, but rarely mimic the human anatomy and physiological hemodynamics, and require significantly more time, cost, and resources. Therefore, emerging strategies are examined that integrate computational and biological models, and the potential of advances in imaging, biofabrication, and machine learning is explored in developing more effective models of atherosclerosis.

20( S )-Protopanaxatriol Improves Atherosclerosis by Inhibiting Low-Density Lipoprotein Receptor Degradation in ApoE KO Mice

ABSTRACT

Atherosclerosis (AS) is a chronic progressive disease caused by various factors and causes various cerebrovascular and cardiovascular diseases (CVDs). Reducing the plasma levels of low-density lipoprotein cholesterol is the primary goal in preventing and treating AS. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in regulating low-density lipoprotein cholesterol metabolism. Panax notoginseng has potent lipid-reducing effects and protects against CVDs, and its saponins induce vascular dilatation, inhibit thrombus formation, and are used in treating CVDs. However, the anti-AS effect of the secondary metabolite, 20( S )-protopanaxatriol (20( S )-PPT), remains unclear. In this study, the anti-AS effect and molecular mechanism of 20( S )-PPT were investigated in vivo and in vitro by Western blotting, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, immunofluorescence staining, and other assays. The in vitro experiments revealed that 20( S )-PPT reduced the levels of PCSK9 in the supernatant of HepG2 cells, upregulated low-density lipoprotein receptor protein levels, promoted low-density lipoprotein uptake by HepG2 cells, and reduced PCSK9 mRNA transcription by upregulating the levels of forkhead box O3 protein and mRNA and decreasing the levels of HNF1α and SREBP2 protein and mRNA. The in vivo experiments revealed that 20( S )-PPT upregulated aortic α-smooth muscle actin expression, increased the stability of atherosclerotic plaques, and reduced aortic plaque formation induced by a high-cholesterol diet in ApoE -/- mice (high-cholesterol diet-fed group). Additionally, 20( S )-PPT reduced the aortic expression of CD68, reduced inflammation in the aortic root, and alleviated the hepatic lesions in the high-cholesterol diet-fed group. The study revealed that 20( S )-PPT inhibited low-density lipoprotein receptor degradation via PCSK9 to alleviate AS.

Advances in the treatment of atherosclerosis with ligand-modified nanocarriers

Atherosclerosis, a chronic disease associated with metabolism, poses a significant risk to human well-being. Currently, existing treatments for atherosclerosis lack sufficient efficiency, while the utilization of surface-modified nanoparticles holds the potential to deliver highly effective therapeutic outcomes. These nanoparticles can target and bind to specific receptors that are abnormally over-expressed in atherosclerotic conditions. This paper reviews recent research (2018-present) advances in various ligand-modified nanoparticle systems targeting atherosclerosis by specifically targeting signature molecules in the hope of precise treatment at the molecular level and concludes with a discussion of the challenges and prospects in this field. The intention of this review is to inspire novel concepts for the design and advancement of targeted nanomedicines tailored specifically for the treatment of atherosclerosis.

WITHDRAWN: Coronary atherosclerotic plaque regression strategies

Ahead of Print article withdrawn by publisher.

Elucidating VSMC phenotypic transition mechanisms to bridge insights into cardiovascular disease implications

Cardiovascular diseases (CVD) are the leading cause of death worldwide, despite advances in understanding cardiovascular health. Significant barriers still exist in effectively preventing and managing these diseases. Vascular smooth muscle cells (VSMCs) are crucial for maintaining vascular integrity and can switch between contractile and synthetic functions in response to stimuli such as hypoxia and inflammation. These transformations play a pivotal role in the progression of cardiovascular diseases, facilitating vascular modifications and disease advancement. This article synthesizes the current understanding of the mechanisms and signaling pathways regulating VSMC phenotypic transitions, highlighting their potential as therapeutic targets in cardiovascular disease interventions.

Targeting Oncostatin M Receptor to Attenuate Carotid Artery Plaque Vulnerability in Hypercholesterolemic Microswine

Atherosclerosis is a chronic inflammatory disease that leads to acute embolism via the formation of atherosclerotic plaques. Plaque formation is first induced by fatty deposition along the arterial intima. Inflammation, bacterial infection, and the released endotoxins can lead to dysfunction and phenotypic changes of vascular smooth muscle cells (VSMCs), advancing the plaque from stable to unstable form and prone to rupture. Stable plaques are characterized by increased VSMCs and less inflammation while vulnerable plaques develop due to chronic inflammation and less VSMCs. Oncostatin M (OSM), an inflammatory cytokine, plays a role in endothelial cells and VSMC proliferation. This effect of OSM could be modulated by p27KIP1, a cyclin-dependent kinase (CDK) inhibitor. However, the role of OSM in plaque vulnerability has not been investigated. To better understand the role of OSM and its downstream signaling including p27KIP1 in plaque vulnerability, we characterized the previously collected carotid arteries from hyperlipidemic Yucatan microswine using hematoxylin and eosin stain, Movat Pentachrome stain, and gene and protein expression of OSM and p27KIP1 using immunostaining and real-time polymerase chain reaction. OSM and p27KIP1 expression in carotid arteries with angioplasty and treatment with either scrambled peptide or LR12, an inhibitor of triggering receptor expressed on myeloid cell (TREM)-1, were compared between the experimental groups and with contralateral carotid artery. The results of this study elucidated the presence of OSM and p27KIP1 in carotid arteries with plaque and their association with arterial plaque and vulnerability. The findings suggest that targeting OSM and p27KIP1 axis regulating VSMC proliferation may have therapeutic significance to stabilize plaque.

IRE1α: from the function to the potential therapeutic target in atherosclerosis

Inositol requiring enzyme 1 (IRE1) is generally thought to control the most conserved pathway in the unfolded protein response (UPR). Two isoforms of IRE1, IRE1α and IRE1β, have been reported in mammals. IRE1α is a ubiquitously expressed protein whose knockout shows marked lethality. In contrast, the expression of IRE1β is exclusively restricted in the epithelial cells of the respiratory and gastrointestinal tracts, and IRE1β-knockout mice are phenotypically normal. As research continues to deepen, IRE1α was showed to be tightly linked to inflammation, lipid metabolism regulation, cell death and so on. Growing evidence also suggests an important role for IRE1α in promoting atherosclerosis (AS) progression and acute cardiovascular events through disrupting lipid metabolism balance, facilitating cells apoptosis, accelerating inflammatory responses and promoting foam cell formation. In addition, IRE1α was recognized as novel potential therapeutic target in AS prevention. This review provides some clues about the relationship between IRE1α and AS, hoping to contribute to further understanding roles of IRE1α in atherogenesis and to be helpful for the design of novel efficacious therapeutics agents targeting IRE1α-related pathways.

CX3CL1 (Fractalkine)-CX3CR1 Axis in Inflammation-Induced Angiogenesis and Tumorigenesis

The chemotactic cytokine fractalkine (FKN, chemokine CX3CL1) has unique properties resulting from the combination of chemoattractants and adhesion molecules. The soluble form (sFKN) has chemotactic properties and strongly attracts T cells and monocytes. The membrane-bound form (mFKN) facilitates diapedesis and is responsible for cell-to-cell adhesion, especially by promoting the strong adhesion of leukocytes (monocytes) to activated endothelial cells with the subsequent formation of an extracellular matrix and angiogenesis. FKN signaling occurs via CX3CR1, which is the only known member of the CX3C chemokine receptor subfamily. Signaling within the FKN-CX3CR1 axis plays an important role in many processes related to inflammation and the immune response, which often occur simultaneously and overlap. FKN is strongly upregulated by hypoxia and/or inflammation-induced inflammatory cytokine release, and it may act locally as a key angiogenic factor in the highly hypoxic tumor microenvironment. The importance of the FKN/CX3CR1 signaling pathway in tumorigenesis and cancer metastasis results from its influence on cell adhesion, apoptosis, and cell migration. This review presents the role of the FKN signaling pathway in the context of angiogenesis in inflammation and cancer. The mechanisms determining the pro- or anti-tumor effects are presented, which are the cause of the seemingly contradictory results that create confusion regarding the therapeutic goals.

Therapeutic Potential of Targeting p27kip1 in Plaque Vulnerability

Atherosclerosis, a critical contributor to coronary artery diseases, involves the accumulation of cholesterol, fibrin, and lipids within arterial walls, inciting inflammatory reactions culminating in plaque formation. This multifaceted interplay encompasses excessive fibrosis, fatty plaque development, vascular smooth muscle cell (VSMC) proliferation, and leukocyte migration in response to inflammatory pathways. While stable plaques demonstrate resilience against complications, vulnerable ones, with lipid-rich cores, necrosis, and thin fibrous caps, lead to thrombosis, myocardial infarction, stroke, and acute cerebrovascular accidents. The nuanced phenotypes of VSMCs, modulated by gene regulation and environmental cues, remain pivotal. Essential markers like alpha-SMA, myosin heavy chain, and calponin regulate VSMC migration and contraction, exhibiting diminished expression during VSMC de-differentiation and proliferation. p27kip, a CDK inhibitor, shows promise in regulating VSMC proliferation and appears associated with TNF-α-induced pathways impacting unstable plaques. Oncostatin M (OSM), an IL-6 family cytokine, correlates with MMP upregulation and foam cell formation, influencing plaque development. Efforts targeting mammalian target of rapamycin (mTOR) inhibition, notably using rapamycin and its analogs, demonstrate potential but pose challenges due to associated adverse effects. Exploration of the impact of p27kip impact on plaque macrophages presents promising avenues, yet its complete therapeutic potential remains untapped. Similarly, while OSM has exhibited potential in inducing cell cycle arrest via p27kip, direct links necessitate further investigation. This critical review discusses the role of mTOR, p27kip, and OSM in VSMC proliferation and differentiation followed by the therapeutic potential of targeting these mediators in atherosclerosis to attenuate plaque vulnerability.

Preclinical evaluation of an 18F-labeled Tenascin-C aptamer for PET imaging of atherosclerotic plaque in mouse models of atherosclerosis

Tenascin-C is an extracellular matrix glycoprotein strongly expressed in coronary atherosclerotic plaque. Aptamers are single-stranded oligonucleotides that bind to specific target molecules with high affinity. This study hypothesized that tenascin-C expression at atherosclerotic plaque in vivo could be detected by tenascin-C specific aptamers using positron emission tomography (PET). This paper reports the radiosynthesis of a fluorine-18 (18F)-labeled tenascin-C aptamer for the biodistribution and PET imaging of the tenascin-C expression in apolipoprotein E-deficient (ApoE-/-) mice. The aortas ApoE-/- mice showed significantly increased positive areas of Oil red O staining than control C57BL/6 mice, and tenascin-C expression was detected in foam cells accumulated in the subendothelial lesions of ApoE-/- mice. The ex vivo biodistribution of the 18F-labeled tenascin-C aptamer showed significantly increased uptake at the aorta of ApoE-/- mice, and ex vivo autoradiography of aorta revealed the high accumulation of the 18F-labeled tenascin-C aptamer in the atherosclerotic lesions of ApoE-/- mice, which was consistent with the location of the atherosclerotic plaques detected by Oil red O staining. PET imaging of the 18F-labeled tenascin-C aptamer revealed a significantly higher mean standardized uptake in the aorta of the ApoE-/- mice than the control C57BL/6 mice. These data highlight the potential use of tenascin-C aptamer to diagnose atherosclerotic lesions in vivo.

G6PD maintains the VSMC synthetic phenotype and accelerates vascular neointimal hyperplasia by inhibiting the VDAC1-Bax-mediated mitochondrial apoptosis pathway

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) plays an important role in vascular smooth muscle cell (VSMC) phenotypic switching, which is an early pathogenic event in various vascular remodeling diseases (VRDs). However, the underlying mechanism is not fully understood.

METHODS

An IP‒LC‒MS/MS assay was conducted to identify new binding partners of G6PD involved in the regulation of VSMC phenotypic switching under platelet-derived growth factor-BB (PDGF-BB) stimulation. Co-IP, GST pull-down, and immunofluorescence colocalization were employed to clarify the interaction between G6PD and voltage-dependent anion-selective channel protein 1 (VDAC1). The molecular mechanisms involved were elucidated by examining the interaction between VDAC1 and apoptosis-related biomarkers, as well as the oligomerization state of VDAC1.

RESULTS

The G6PD level was significantly elevated and positively correlated with the synthetic characteristics of VSMCs induced by PDGF-BB. We identified VDAC1 as a novel G6PD-interacting molecule essential for apoptosis. Specifically, the G6PD-NTD region was found to predominantly contribute to this interaction. G6PD promotes VSMC survival and accelerates vascular neointimal hyperplasia by inhibiting VSMC apoptosis. Mechanistically, G6PD interacts with VDAC1 upon stimulation with PDGF-BB. By competing with Bax for VDAC1 binding, G6PD reduces VDAC1 oligomerization and counteracts VDAC1-Bax-mediated apoptosis, thereby accelerating neointimal hyperplasia.

CONCLUSION

Our study showed that the G6PD-VDAC1-Bax axis is a vital switch in VSMC apoptosis and is essential for VSMC phenotypic switching and neointimal hyperplasia, providing mechanistic insight into early VRDs.

FTO Stabilizes MIS12 to Inhibit Vascular Smooth Muscle Cell Senescence in Atherosclerotic Plaque

Purpose

Atherosclerosis is the main cause of atherosclerotic cardiovascular disease (CVD). Here, we aimed to uncover the role and mechanisms of fat mass and obesity-associated genes (FTO) in the regulation of vascular smooth muscle cell (VSMC) senescence in atherosclerotic plaques.

Methods

ApoE-/- mice fed a high-fat diet (HFD) were used to establish an atherosclerotic animal model. Immunohistochemistry, and the staining of hematoxylin-eosin, Oil Red O, Sirius red, and Masson were performed to confirm the role of FTO in atherosclerosis in vivo. Subsequently, FTO expression in primary VSMCs is either upregulated or downregulated. Oxidized low-density lipoprotein (ox-LDL) was used to treat VSMCs, followed by EdU staining, flow cytometry, senescence-associated β-galactosidase (SA-β-gal) staining, immunofluorescence, telomere detection, RT-qPCR, and Western blotting to determine the molecular mechanisms by which FTO inhibits VSMC senescence.

Results

Decreased FTO expression was observed in progressive atherosclerotic plaques of ApoE-/- mice fed with HFD. FTO upregulation inhibits atherosclerotic lesions in mice. FTO inhibits VSMC aging in atherosclerotic plaques by helping VSMC withstand ox-LDL-induced cell cycle arrest and senescence. This process is achieved by stabilizing the MIS12 protein in VSMC through a proteasome-mediated pathway.

Conclusion

FTO inhibits VSMC senescence and subsequently slows the progression of atherosclerotic plaques by stabilizing the MIS12 protein.

Utilization of an Artery-on-a-Chip to Unravel Novel Regulators and Therapeutic Targets in Vascular Diseases

In this study, organ-on-chip technology is used to develop an in vitro model of medium-to-large size arteries, the artery-on-a-chip (AoC), with the objective to recapitulate the structure of the arterial wall and the relevant hemodynamic forces affecting luminal cells. AoCs exposed either to in vivo-like shear stress values or kept in static conditions are assessed to generate a panel of novel genes modulated by shear stress. Considering the crucial role played by shear stress alterations in carotid arteries affected by atherosclerosis (CAD) and abdominal aortic aneurysms (AAA) disease development/progression, a patient cohort of hemodynamically relevant specimens is utilized, consisting of diseased and non-diseased (internal control) vessel regions from the same patient. Genes activated by shear stress follow the same expression pattern in non-diseased segments of human vessels. Single cell RNA sequencing (scRNA-seq) enables to discriminate the unique cell subpopulations between non-diseased and diseased vessel portions, revealing an enrichment of flow activated genes in structural cells originating from non-diseased specimens. Furthermore, the AoC served as a platform for drug-testing. It reproduced the effects of a therapeutic agent (lenvatinib) previously used in preclinical AAA studies, therefore extending the understanding of its therapeutic effect through a multicellular structure.

Photodynamic Therapy for Atherosclerosis

Atherosclerosis, which currently contributes to 31% of deaths globally, is of critical cardiovascular concern. Current diagnostic tools and biomarkers are limited, emphasizing the need for early detection. Lifestyle modifications and medications form the basis of treatment, and emerging therapies such as photodynamic therapy are being developed. Photodynamic therapy involves a photosensitizer selectively targeting components of atherosclerotic plaques. When activated by specific light wavelengths, it induces localized oxidative stress aiming to stabilize plaques and reduce inflammation. The key advantage lies in its selective targeting, sparing healthy tissues. While preclinical studies are encouraging, ongoing research and clinical trials are crucial for optimizing protocols and ensuring long-term safety and efficacy. The potential combination with other therapies makes photodynamic therapy a versatile and promising avenue for addressing atherosclerosis and associated cardiovascular disease. The investigations underscore the possibility of utilizing photodynamic therapy as a valuable treatment choice for atherosclerosis. As advancements in research continue, photodynamic therapy might become more seamlessly incorporated into clinical approaches for managing atherosclerosis, providing a blend of efficacy and limited invasiveness.

Proliferation, migration and phenotypic transformation of VSMC induced via Hcy related to up-expression of WWP2 and p-STAT3

To provide a theoretical basis for the prevention and treatment of atherosclerosis (AS), the current study aimed to investigate the mechanism underlying the effect of homocysteine (Hcy) on regulating the proliferation, migration and phenotypic transformation of vascular smooth muscle cells (VSMC) via sirtuin-1 (SIRT1)/signal transducer and activator of transcription 3 (STAT3) through Nedd4-like E3 ubiquitin-protein ligase WWP2 (WWP2). Here, Based on the establishment of ApoE-/- mouse models of high Hcy As and the model of Hcy stimulation of VSMC in vitro to observe the interaction between WWP2 and STAT3 and its effect on the proliferation, migration, and phenotypic transformation of Hcy-induced VSMC, which has not been previously reported. This study revealed that WWP2 could promote the proliferation, migration, and phenotype switch of Hcy-induced VSMC by up-regulating the phosphorylation of SIRT1/STAT3 signaling. Furthermore, Hcy might up-regulate WWP2 expression by inhibiting histone H3K27me3 expression through up-regulated UTX. These data suggest that WWP2 is a novel and important regulator of Hcy-induced VSMC proliferation, migration, and phenotypic transformation.

Purification, structural characteristics and anti-atherosclerosis activity of a novel green tea polysaccharide

A new homogeneous polysaccharide (TPS3A) was isolated and purified from Tianzhu Xianyue fried green tea by DEAE-52 cellulose and Sephacryl S-500 column chromatography. Structural characterization indicated that TPS3A mainly consisted of arabinose, galactose, galacturonic acid and rhamnose in a molar ratio of 5.84: 4.15: 2.06: 1, with an average molecular weight of 1.596 × 104 kDa. The structure of TPS3A was characterized as a repeating unit consisting of 1,3-Galp, 1,4-Galp, 1,3,6-Galp, 1,3-Araf, 1,5-Araf, 1,2,4-Rhap and 1-GalpA, with two branches on the C6 of 1,3,6-Galp and C2 of 1,2,4-Rhap, respectively. To investigate the preventive effects of TPS3A on atherosclerosis, TPS3A was administered orally to ApoE-deficient (ApoE-/-) mice. Results revealed that TPS3A intervention could effectively delay the atherosclerotic plaque progression, modulate dyslipidemia, and reduce the transformation of vascular smooth muscle cells (VSMCs) from contractile phenotype to synthetic phenotype by activating the expression of contractile marker alpha-smooth muscle actin (α-SMA) and inhibiting the expression of synthetic marker osteopontin (OPN) in high-fat diet-induced ApoE-/- mice. Our findings suggested that TPS3A markedly alleviated atherosclerosis by regulating dyslipidemia and phenotypic transition of VSMCs, and might be used as a novel functional ingredient to promote cardiovascular health.

Effect of Mechanical Stimuli on the Phenotypic Plasticity of Induced Pluripotent Stem-Cell-Derived Vascular Smooth Muscle Cells in a 3D Hydrogel

Introduction: Vascular smooth muscle cells (VSMCs) play a pivotal role in vascular homeostasis, with dysregulation leading to vascular complications. Human-induced pluripotent stem-cell (hiPSC)-derived VSMCs offer prospects for personalized disease modeling and regenerative strategies. Current research lacks comparative studies on the impact of three-dimensional (3D) substrate properties under cyclic strain on phenotypic adaptation in hiPSC-derived VSMCs. Here, we aim to investigate the impact of intrinsic substrate properties, such as the hydrogel's elastic modulus and cross-linking density in a 3D static and dynamic environment, on the phenotypical adaptation of human mural cells derived from hiPSC-derived organoids (ODMCs), compared to aortic VSMCs. Methods and results: ODMCs were cultured in two-dimensional (2D) conditions with synthetic or contractile differentiation medium or in 3D Gelatin Methacryloyl (GelMa) substrates with varying degrees of functionalization and percentages to modulate Young's modulus and cross-linking density. Cells in 3D substrates were exposed to cyclic, unidirectional strain. Phenotype characterization was conducted using specific markers through immunofluorescence and gene expression analysis. Under static 2D culture, ODMCs derived from hiPSCs exhibited a VSMC phenotype, expressing key mural markers, and demonstrated a level of phenotypic plasticity similar to primary human VSMCs. In static 3D culture, a substrate with a higher Young's modulus and cross-linking density promoted a contractile phenotype in ODMCs and VSMCs. Dynamic stimulation in the 3D substrate promoted a switch toward a contractile phenotype in both cell types. Conclusion: Our study demonstrates phenotypic plasticity of human ODMCs in response to 2D biological and 3D mechanical stimuli that equals that of primary human VSMCs. These findings may contribute to the advancement of tailored approaches for vascular disease modeling and regenerative strategies.

In vitro and in vivo approaches to assess atherosclerosis following exposure to low-dose mixtures of arsenic and cadmium

Worldwide, millions of people are co-exposed to arsenic and cadmium. Environmental exposure to both metals is linked with a higher risk of atherosclerosis. While studies have characterized the pro-atherosclerotic effects of arsenic and cadmium as single agents, little is known about the potential effects of metal mixtures, particularly at low doses. Here, we used a combination of in vitro and in vivo models to assess the effects of low-dose metals individually and as mixtures on early events and plaque development associated with atherosclerosis. In vitro, we investigated early pro-atherogenic changes in macrophages and endothelial cells with metal treatments. The combined cytotoxic effects of both metals at low concentrations were dose interactive, specifically, synergistic in macrophages, but antagonistic in endothelial cells. Despite this differential behavior across cell types, the mixtures did not initiate early pro-atherogenic events: neither reactive oxygen species generation in macrophages nor adhesion molecule expression on endothelial cells. In vivo, we utilized the well-characterized hyperlipidemic apolipoprotein E knock-out (ApoE-/-) mouse model. Previously, we have shown that low concentrations of arsenic (down to 10 ppb) enhance atherosclerosis in ApoE-/- mice. This model has also been used with cadmium to demonstrate pro-atherogenic effects, although at concentrations above human-relevant exposures. In both sexes, there are some small increases in atherosclerotic lesion size, but very few changes in plaque constituents in the ApoE-/- mouse model. Together, these results suggests that low-dose metal mixtures are not significantly more pro-atherogenic than either metal alone.

Role of vascular smooth muscle cell clonality in atherosclerosis

Atherosclerotic cardiovascular disease remains the leading cause of death worldwide. While many cell types contribute to the growing atherosclerotic plaque, the vascular smooth muscle cell (SMC) is a major contributor due in part to its remarkable plasticity and ability to undergo phenotype switching in response to injury. SMCs can migrate into the fibrous cap, presumably stabilizing the plaque, or accumulate within the lesional core, possibly accelerating vascular inflammation. How SMCs expand and react to disease stimuli has been a controversial topic for many decades. While early studies relying on X-chromosome inactivation were inconclusive due to low resolution and sensitivity, recent advances in multi-color lineage tracing models have revitalized the concept that SMCs likely expand in an oligoclonal fashion during atherogenesis. Current efforts are focused on determining whether all SMCs have equal capacity for clonal expansion or if a "stem-like" progenitor cell may exist, and to understand how constituents of the clone decide which phenotype they will ultimately adopt as the disease progresses. Mechanistic studies are also beginning to dissect the processes which confer cells with their overall survival advantage, test whether these properties are attributable to intrinsic features of the expanding clone, and define the role of cross-talk between proliferating SMCs and other plaque constituents such as neighboring macrophages. In this review, we aim to summarize the historical perspectives on SMC clonality, highlight unanswered questions, and identify translational issues which may need to be considered as therapeutics directed against SMC clonality are developed as a novel approach to targeting atherosclerosis.

Ficolin-2 amplifies inflammation in macrophage-smooth muscle cell cross-talk and increases monocyte transmigration by mechanisms involving IL-1β and IL-6

Ficolin-2, recently identified in atherosclerotic plaques, has been correlated with future acute cardiovascular events, but its role remains unknown. We hypothesize that it could influence plaque vulnerability by interfering in the cross-talk between macrophages (MØ) and smooth muscle cells (SMC). To examine its role and mechanism of action, we exposed an in-vitro co-culture system of SMC and MØ to ficolin-2 (10 µg/mL) and then performed cytokine array, protease array, ELISA, qPCR, Western Blot, and monocyte transmigration assay. Carotid plaque samples from atherosclerotic patients with high plasma levels of ficolin-2 were analyzed by immunofluorescence. We show that ficolin-2: (i) promotes a pro-inflammatory phenotype in SMC following interaction with MØ by elevating the gene expression of MCP-1, upregulating gene and protein expression of IL-6 and TLR4, and by activating ERK/MAPK and NF-KB signaling pathways; (ii) increased IL-1β, IL-6, and MIP-1β in MØ beyond the level induced by cellular interaction with SMC; (iii) elevated the secretion of IL-1β, IL-6, and CCL4 in the conditioned medium; (iv) enhanced monocyte transmigration and (v) in atherosclerotic plaques from patients with high plasma levels of ficolin-2, we observed co-localization of ficolin-2 with SMC marker αSMA and the cytokines IL-1β and IL-6. These findings shed light on previously unknown mechanisms underlying ficolin-2-dependent pathological inflammation in atherosclerotic plaques.

The microenvironment of the atheroma expresses phenotypes of plaque instability

Data from histopathology studies of human atherosclerotic tissue specimens and from vascular imaging studies support the concept that the local arterial microenvironment of a stable atheroma promotes destabilizing conditions that result in the transition to an unstable atheroma. Destabilization is characterized by several different plaque phenotypes that cause major clinical events such as acute coronary syndrome and cerebrovascular strokes. There are several rupture-associated phenotypes causing thrombotic vascular occlusion including simple fibrous cap rupture of an atheroma, fibrous cap rupture at site of previous rupture-and-repair of an atheroma, and nodular calcification with rupture. Endothelial erosion without rupture has more recently been shown to be a common phenotype to promote thrombosis as well. Microenvironment features that are linked to these phenotypes of plaque instability are neovascularization arising from the vasa vasorum network leading to necrotic core expansion, intraplaque hemorrhage, and cap rupture; activation of adventitial and perivascular adipose tissue cells leading to secretion of cytokines, growth factors, adipokines in the outer artery wall that destabilize plaque structure; and vascular smooth muscle cell phenotypic switching through transdifferentiation and stem/progenitor cell activation resulting in the promotion of inflammation, calcification, and secretion of extracellular matrix, altering fibrous cap structure, and necrotic core growth. As the technology evolves, studies using noninvasive vascular imaging will be able to investigate the transition of stable to unstable atheromas in real time. A limitation in the field, however, is that reliable and predictable experimental models of spontaneous plaque rupture and/or erosion are not currently available to study the cell and molecular mechanisms that regulate the conversion of the stable atheroma to an unstable plaque.

Role of oncostatin-M in ECM remodeling and plaque vulnerability

Atherosclerosis is a multifactorial inflammatory disease characterized by the development of plaque formation leading to occlusion of the vessel and hypoxia of the tissue supplied by the vessel. Chronic inflammation and altered collagen expression render stable plaque to unstable and increase plaque vulnerability. Thinned and weakened fibrous cap results in plaque rupture and formation of thrombosis and emboli formation leading to acute ischemic events such as stroke and myocardial infarction. Inflammatory mediators including TREM-1, TLRs, MMPs, and immune cells play a critical role in plaque vulnerability. Among the other inflammatory mediators, oncostatin-M (OSM), a pro-inflammatory cytokine, play an important role in the development and progression of atherosclerosis, however, the role of OSM in plaque vulnerability and extracellular matrix remodeling (ECM) is not well understood and studied. Since ECM remodeling plays an important role in atherosclerosis and plaque vulnerability, a detailed investigation on the role of OSM in ECM remodeling and plaque vulnerability is critical. This is important because the role of OSM has been discussed in the context of proliferation of vascular smooth muscle cells and regulation of cytokine expression but the role of OSM is scarcely discussed in relation to ECM remodeling and plaque vulnerability. This review focuses on critically discussing the role of OSM in ECM remodeling and plaque vulnerability.

Smooth muscle differentiation of coronary intima in autopsy tissues after sirolimus-eluting stent implantation

BACKGROUND

In coronary atherosclerotic disease, the proliferation of intimal smooth muscle cells (SMCs) is regarded as beneficial with respect to stable and unstable plaques, but is thought detrimental in discussions on coronary stent restenosis. To resolve this discrepancy, we focused on the quality, not quantity, of intimal SMCs in coronary atherosclerotic disease.

METHODS

Autopsied coronary artery specimens from seven patients implanted with bare metal stents (BMS), three with paclitaxel-eluting stents (PES), and 10 with sirolimus (rapamycin)-eluting stents (SES) were immunostained for SMC markers. Cultured human coronary artery SMCs were also treated with sirolimus and paclitaxel.

RESULTS

Intimal SMC differentiation, estimated by the ratio of h-caldesmon+ cells to α-smooth muscle actin+ (α-SMA+) cells, was significantly increased whereas dedifferentiation, estimated from the ratio of fibroblast activation protein alpha (FAPα)+ cells to α-SMA+ cells, was significantly decreased, in tissues of SES compared with BMS cases. No difference in the degree of differentiation was found between PES and BMS cases or between the three groups in nonstented arteries used as controls. Correlation analyses for each field of view revealed a significant positive correlation between h-caldesmon and calponin staining but significant negative correlations with FAPα staining in α-SMA+ cells. Cultured SMCs were shorter (dedifferentiated) and showed an increased FAPα/α-SMA protein when treated with paclitaxel, whereas they became elongated (differentiated) and showed increased calponin/α-SMA proteins with sirolimus.

CONCLUSIONS

The SMCs of the coronary intima may differentiate after SES implantation. SMC differentiation may explain both the plaque stabilization and reduced risk of reintervention associated with SES.

Knowledge fields and emerging trends about extracellular matrix in carotid artery disease from 1990 to 2021: analysis of the scientific literature

BACKGROUND

Stroke is a heavy burden in modern society, and carotid artery disease is a major cause. The role of the extracellular matrix (ECM) in the development and progression of carotid artery disease has become a popular research focus. However, there is no published bibliometric analysis to derive the main publication features and trends in this scientific area. We aim to conduct a bibliometric analysis to reveal current status of ECM in carotid artery disease and to predict future hot spots.

METHODS

We searched and downloaded articles from the Web of Science Core Collection with "Carotid" and "Extracellular Matrix" as subject words from 1990 to 2021. The complete bibliographic data were analyzed by Bibliometrics, BICOMB, gCLUTO and CiteSpace softwares.

RESULTS

Since 1990, the United States has been the leader in the number of publications in the field of ECM in carotid artery disease, followed by China, Japan and Germany. Among institutions, Institut National De La Sante Et De La Recherche Medicale Inserm, University of Washington Seattle and Harvard University are in the top 3. "Arteriosclerosis Thrombosis and Vascular Biology" is the most popular journal and "Circulation" is the most cited journal. "Clowes AW", "Hedin Ulf" and "Nilsson Jan" are the top three authors of published articles. Finally, we investigated the frontiers through the strongest citation bursts, conducted keyword biclustering analysis, and discovered five clusters of research hotspots. Our research provided a comprehensive analysis of the fundamental data, knowledge organization, and dynamic evolution of research about ECM in carotid artery disease.

CONCLUSIONS

The field of ECM in carotid artery disease has received increasing attention. We summarized the history of the field and predicted five future hotspots through bibliometric analysis. This study provided a reference for researchers in this fields, and the methodology can be extended to other fields.

HOXA1 participates in VSMC-to-macrophage-like cell transformation via regulation of NF-κB p65 and KLF4: a potential mechanism of atherosclerosis pathogenesis

BACKGROUND

Macrophage-like transformation of vascular smooth muscle cells (VSMCs) is a risk factor of atherosclerosis (AS) progression. Transcription factor homeobox A1 (HOXA1) plays functional roles in differentiation and development. This study aims to explore the role of HOXA1 in VSMC transformation, thereby providing evidence for the potential mechanism of AS pathogenesis.

METHODS

High fat diet (HFD)-fed apolipoprotein E knockout (ApoE^-/-) mice were applied as an in vivo model to imitate AS, while 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POV-PC)-treated VSMCs were applied as an in vitro model. Recombinant adeno-associated-virus-1 (AAV-1) vectors that express short-hairpin RNAs targeting HOXA1, herein referred as AAV1-shHOXA1, were generated for the loss-of-function experiments throughout the study.

RESULTS

In the aortic root of AS mice, lipid deposition was severer and HOXA1 expression was higher than the wide-type mice fed with normal diet or HFD. Silencing of HOXA1 inhibited the AS-induced weight gain, inflammatory response, serum and liver lipid metabolism disorder and atherosclerotic plaque formation. Besides, lesions from AS mice with HOXA1 knockdown showed less trans-differentiation of VSMCs to macrophage-like cells, along with a suppression of krüppel-like factor 4 (KLF4) and nuclear factor (NF)-κB RelA (p65) expression. In vitro experiments consistently confirmed that HOXA1 knockdown suppressed lipid accumulation, VSMC-to-macrophage phenotypic switch and inflammation in POV-PC-treated VSMCs. Mechanism investigations further illustrated that HOXA1 transcriptionally activated RelA and KLF4 to participate in the pathological manifestations of VSMCs.

CONCLUSIONS

HOXA1 participates in AS progression by regulating VSMCs plasticity via regulation of NF-κB p65 and KLF4. HOXA1 has the potential to be a biomarker or therapeutic target for AS.

Smooth Muscle Heterogeneity and Plasticity in Health and Aortic Aneurysmal Disease

Vascular smooth muscle cells (VSMCs) are the predominant cell type in the medial layer of the aorta, which plays a critical role in the maintenance of aortic wall integrity. VSMCs have been suggested to have contractile and synthetic phenotypes and undergo phenotypic switching to contribute to the deteriorating aortic wall structure. Recently, the unprecedented heterogeneity and diversity of VSMCs and their complex relationship to aortic aneurysms (AAs) have been revealed by high-resolution research methods, such as lineage tracing and single-cell RNA sequencing. The aortic wall consists of VSMCs from different embryonic origins that respond unevenly to genetic defects that directly or indirectly regulate VSMC contractile phenotype. This difference predisposes to hereditary AAs in the aortic root and ascending aorta. Several VSMC phenotypes with different functions, for example, secreting VSMCs, proliferative VSMCs, mesenchymal stem cell-like VSMCs, immune-related VSMCs, proinflammatory VSMCs, senescent VSMCs, and stressed VSMCs are identified in non-hereditary AAs. The transformation of VSMCs into different phenotypes is an adaptive response to deleterious stimuli but can also trigger pathological remodeling that exacerbates the pathogenesis and development of AAs. This review is intended to contribute to the understanding of VSMC diversity in health and aneurysmal diseases. Papers that give an update on VSMC phenotype diversity in health and aneurysmal disease are summarized and recent insights on the role of VSMCs in AAs are discussed.

LncRNAs as Regulators of Atherosclerotic Plaque Stability

Current clinical data show that, despite constant efforts to develop novel therapies and clinical approaches, atherosclerotic cardiovascular diseases (ASCVD) are still one of the leading causes of death worldwide. Advanced and unstable atherosclerotic plaques most often trigger acute coronary events that can lead to fatal outcomes. However, despite the fact that different plaque phenotypes may require different treatments, current approaches to prognosis, diagnosis, and classification of acute coronary syndrome do not consider the diversity of plaque phenotypes. Long non-coding RNAs (lncRNAs) represent an important class of molecules that are implicated in epigenetic control of numerous cellular processes. Here we review the latest knowledge about lncRNAs' influence on plaque development and stability through regulation of immune response, lipid metabolism, extracellular matrix remodelling, endothelial cell function, and vascular smooth muscle function, with special emphasis on pro-atherogenic and anti-atherogenic lncRNA functions. In addition, we present current challenges in the research of lncRNAs' role in atherosclerosis and translation of the findings from animal models to humans. Finally, we present the directions for future lncRNA-oriented research, which may ultimately result in patient-oriented therapeutic strategies for ASCVD.

Target and Cell Therapy for Atherosclerosis and CVD

Cardiovascular diseases (CVD) and, in particular, atherosclerosis, remain the main cause of death in the world today. Unfortunately, in most cases, CVD therapy begins after the onset of clinical symptoms and is aimed at eliminating them. In this regard, early pathogenetic therapy for CVD remains an urgent problem in modern science and healthcare. Cell therapy, aimed at eliminating tissue damage underlying the pathogenesis of some pathologies, including CVD, by replacing it with various cells, is of the greatest interest. Currently, cell therapy is the most actively developed and potentially the most effective treatment strategy for CVD associated with atherosclerosis. However, this type of therapy has some limitations. In this review, we have tried to summarize the main targets of cell therapy for CVD and atherosclerosis in particular based on the analysis using the PubMed and Scopus databases up to May 2023.

Neutrophil-specific STAT4 deficiency attenuates atherosclerotic burden and improves plaque stability via reduction in neutrophil activation and recruitment into aortas of Ldlr-/- mice

Background and aims

Neutrophils drive atheroprogression and directly contribute to plaque instability. We recently identified signal transducer and activator of transcription 4 (STAT4) as a critical component for bacterial host defense in neutrophils. The STAT4-dependent functions of neutrophils in atherogenesis are unknown. Therefore, we investigated a contributory role of STAT4 in neutrophils during advanced atherosclerosis.

Methods

We generated myeloid-specific Stat4^ΔLysMLdlr^-/-, neutrophil-specific Stat4^ΔS100A8Ldlr^-/-, and control Stat4^fl/flLdlr^-/- mice. All groups were fed a high-fat/cholesterol diet (HFD-C) for 28 weeks to establish advanced atherosclerosis. Aortic root plaque burden and stability were assessed histologically by Movat pentachrome staining. Nanostring gene expression analysis was performed on isolated blood neutrophils. Flow cytometry was utilized to analyze hematopoiesis and blood neutrophil activation. In vivo homing of neutrophils to atherosclerotic plaques was performed by adoptively transferring prelabeled Stat4^ΔLysMLdlr^-/- and Stat4^fl/flLdlr^-/- bone marrow cells into aged atherosclerotic Apoe^-/- mice and detected by flow cytometry.

Results

STAT4 deficiency in both myeloid-specific and neutrophil-specific mice provided similar reductions in aortic root plaque burden and improvements in plaque stability via reduction in necrotic core size, improved fibrous cap area, and increased vascular smooth muscle cell content within the fibrous cap. Myeloid-specific STAT4 deficiency resulted in decreased circulating neutrophils via reduced production of granulocyte-monocyte progenitors in the bone marrow. Neutrophil activation was dampened in HFD-C fed Stat4^ΔLysMLdlr^-/- mice via reduced mitochondrial superoxide production, attenuated surface expression of degranulation marker CD63, and reduced frequency of neutrophil-platelet aggregates. Myeloid-specific STAT4 deficiency diminished expression of chemokine receptors CCR1 and CCR2 and impaired in vivo neutrophil trafficking to atherosclerotic aorta.

Conclusions

Our work indicates a pro-atherogenic role for STAT4-dependent neutrophil activation and how it contributes to multiple factors of plaque instability during advanced atherosclerosis in mice.

Cellular mechanisms of oligoclonal vascular smooth muscle cell expansion in cardiovascular disease

AIMS

Quiescent, differentiated adult vascular smooth muscle cells (VSMCs) can be induced to proliferate and switch phenotype. Such plasticity underlies blood vessel homeostasis and contributes to vascular disease development. Oligoclonal VSMC contribution is a hallmark of end-stage vascular disease. Here, we aim to understand cellular mechanisms underpinning generation of this VSMC oligoclonality.

METHODS AND RESULTS

We investigate the dynamics of VSMC clone formation using confocal microscopy and single-cell transcriptomics in VSMC-lineage-traced animal models. We find that activation of medial VSMC proliferation occurs at low frequency after vascular injury and that only a subset of expanding clones migrate, which together drives formation of oligoclonal neointimal lesions. VSMC contribution in small atherosclerotic lesions is typically from one or two clones, similar to observations in mature lesions. Low frequency (<0.1%) of clonal VSMC proliferation is also observed in vitro. Single-cell RNA-sequencing revealed progressive cell state changes across a contiguous VSMC population at onset of injury-induced proliferation. Proliferating VSMCs mapped selectively to one of two distinct trajectories and were associated with cells showing extensive phenotypic switching. A proliferation-associated transitory state shared pronounced similarities with atypical SCA1+ VSMCs from uninjured mouse arteries and VSMCs in healthy human aorta. We show functionally that clonal expansion of SCA1+ VSMCs from healthy arteries occurs at higher rate and frequency compared with SCA1- cells.

CONCLUSION

Our data suggest that activation of proliferation at low frequency is a general, cell-intrinsic feature of VSMCs. We show that rare VSMCs in healthy arteries display VSMC phenotypic switching akin to that observed in pathological vessel remodelling and that this is a conserved feature of mouse and human healthy arteries. The increased proliferation of modulated VSMCs from healthy arteries suggests that these cells respond more readily to disease-inducing cues and could drive oligoclonal VSMC expansion.

Nicotine exacerbates atherosclerosis and plaque instability via NLRP3 inflammasome activation in vascular smooth muscle cells

Rationale: Nicotine has been reported to be a strong risk factor for atherosclerosis. However, the underlying mechanism by which nicotine controls atherosclerotic plaque stability remain largely unknown. Objective: The aim of this study was to evaluate the impact of lysosomal dysfunction mediated NLRP3 inflammasome activation in vascular smooth muscle cell (VSMC) on atherosclerotic plaque formation and stability in advanced atherosclerosis at the brachiocephalic arteries (BA). Methods and Results: Features of atherosclerotic plaque stability and the markers for NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome were monitored in the BA from nicotine or vehicle-treated apolipoprotein E deficient (Apoe-/-) mice fed with Western-type diet (WD). Nicotine treatment for 6 weeks accelerated atherosclerotic plaque formation and enhanced the hallmarks of plaque instability in BA of Apoe-/- mice. Moreover, nicotine elevated interleukin 1 beta (IL-1β) in serum and aorta and was preferred to activate NLRP3 inflammasome in aortic vascular smooth muscle cells (VSMC). Importantly, pharmacological inhibition of Caspase1, a key downstream target of NLRP3 inflammasome complex, and genetic inactivation of NLRP3 significantly restrained nicotine-elevated IL-1β in serum and aorta, as well as nicotine-stimulated atherosclerotic plaque formation and plaque destabilization in BA. We further confirmed the role of VSMC-derived NLRP3 inflammasome in nicotine-induced plaque instability by using VSMC specific TXNIP (upstream regulator of NLRP3 inflammasome) deletion mice. Mechanistic study further showed that nicotine induced lysosomal dysfunction resulted in cathepsin B cytoplasmic release. Inhibition or knockdown of cathepsin B blocked nicotine-dependent inflammasome activation. Conclusions: Nicotine promotes atherosclerotic plaque instability by lysosomal dysfunction-mediated NLRP3 inflammasome activation in vascular smooth muscle cells.

Homeobox A9 is a novel mediator of vascular smooth muscle cell phenotypic switching and proliferation by regulating methyl-CpG binding protein 2

Aberrant proliferation and phenotypic switching of vascular smooth muscle cells (VSMCs) are considered to be the main pathological processes of atherosclerotic plaque formation. Methyl-CpG binding protein 2 (MECP2) affects cell differentiation via modulating VSMC-specific gene expression and acts as a driver for the development of atherosclerosis (AS). Here, we aimed to elucidate (Rafieian-Kopaei et al., 2014 [1]) the role of homeobox A9 (HOXA9) on aberrant VSMCs upon injury or AS, and (Rana et al., 2021 [2]) whether HOXA9-mediated VSMC injury was associated with MECP2. Adeno-associated virus serotype 8-mediated knockdown of HOXA9 rescued aortic pathological injury of apolipoprotein E-deficient (ApoE^-/-) mice fed a high-fat diet (HFD), characterized by the reduction of lipid accumulation and foam cell formation. Further in vitro evidence suggested that proliferation and migration of primary mouse VSMCs (mVSMCs) stimulated by oxidized low-density lipoprotein (ox-LDL) were inhibited after HOXA9 silencing. In addition, HOXA9 silencing blocked VSMC phenotypic switching from contractile to a pathological synthetic state. HOXA9 overexpression caused opposite alterations in ox-LDL-stimulated mVSMCs. Mechanistically, MECP2 was transcriptionally activated by HOXA9. Forced expression of MECP2 impaired the anti-proliferation, anti-migration, and phenotypic switching abilities of HOXA9 silencing in VSMCs upon ox-LDL stimulation. Collectively, our findings reveal that the role of HOXA9 in pathological vascular remodeling may attribute to transcriptional regulation of MECP2.

Proteotoxic stress response in atherosclerotic cardiovascular disease: Emerging role of heat shock factor 1

Atherosclerosis is a major risk factor for cardiovascular diseases. Hypercholesterolemia has been both clinically and experimentally linked to cardiovascular disease and is involved in the initiation of atherosclerosis. Heat shock factor 1 (HSF1) is involved in the control of atherosclerosis. HSF1 is a critical transcriptional factor of the proteotoxic stress response that regulates the production of heat shock proteins (HSPs) and other important activities such as lipid metabolism. Recently, HSF1 is reported to directly interact with and inhibit AMP-activated protein kinase (AMPK) to promote lipogenesis and cholesterol synthesis. This review highlights roles of HSF1 and HSPs in critical metabolic pathways of atherosclerosis, including lipogenesis and proteome homeostasis.

Smooth Muscle Cell Phenotypic Switch Induced by Traditional Cigarette Smoke Condensate: A Holistic Overview

Cigarette smoke (CS) is a risk factor for inflammatory diseases, such as atherosclerosis. CS condensate (CSC) contains lipophilic components that may represent a systemic cardiac risk factor. To better understand CSC effects, we incubated mouse and human aortic smooth muscle cells (SMCs) with CSC. We evaluated specific markers for contractile [i.e., actin, aortic smooth muscle (ACTA2), calponin-1 (CNN1), the Kruppel-like factor 4 (KLF4), and myocardin (MYOCD) genes] and inflammatory [i.e., IL-1β, and IL-6, IL-8, and galectin-3 (LGALS-3) genes] phenotypes. CSC increased the expression of inflammatory markers and reduced the contractile ones in both cell types, with KLF4 modulating the SMC phenotypic switch. Next, we performed a mass spectrometry-based differential proteomic approach on human SMCs and could show 11 proteins were significantly affected by exposition to CSC (FC ≥ 2.7, p ≤ 0.05). These proteins are active in signaling pathways related to expression of pro-inflammatory cytokines and IFN, inflammasome assembly and activation, cytoskeleton regulation and SMC contraction, mitochondrial integrity and cellular response to oxidative stress, proteostasis control via ubiquitination, and cell proliferation and epithelial-to-mesenchymal transition. Through specific bioinformatics resources, we showed their tight functional correlation in a close interaction niche mainly orchestrated by the interferon-induced double-stranded RNA-activated protein kinase (alternative name: protein kinase RNA-activated; PKR) (EIF2AK2/PKR). Finally, by combining gene expression and protein abundance data we obtained a hybrid network showing reciprocal integration of the CSC-deregulated factors and indicating KLF4 and PKR as the most relevant factors.

Neutrophil-specific STAT4 deficiency attenuates atherosclerotic burden and improves plaque stability via reduction in neutrophil activation and recruitment into aortas of Ldlr -/- mice

Background and Aims

Neutrophils drive atheroprogression and directly contribute to plaque instability. We recently identified signal transducer and activator of transcription 4 (STAT4) as a critical component for bacterial host defense in neutrophils. The STAT4-dependent functions of neutrophils in atherogenesis are unknown. Therefore, we investigated a contributory role of STAT4 in neutrophils during advanced atherosclerosis.

Methods

We generated myeloid-specific Stat4 ^ΔLysM Ldlr ^-/- , neutrophil-specific Stat4 ^ΔS100A8 Ldlr ^-/- , and control Stat4 ^fl/fl Ldlr ^-/- mice. All groups were fed a high-fat/cholesterol diet (HFD-C) for 28 weeks to establish advanced atherosclerosis. Aortic root plaque burden and stability were assessed histologically by Movat Pentachrome staining. Nanostring gene expression analysis was performed on isolated blood neutrophils. Flow cytometry was utilized to analyze hematopoiesis and blood neutrophil activation. In vivo homing of neutrophils to atherosclerotic plaques was performed by adoptively transferring prelabeled Stat4 ^ΔLysM Ldlr ^-/- and Stat4 ^fl/fl Ldlr ^-/- bone marrow cells into aged atherosclerotic Apoe ^-/- mice and detected by flow cytometry.

Results

STAT4 deficiency in both myeloid-specific and neutrophil-specific mice provided similar reductions in aortic root plaque burden and improvements in plaque stability via reduction in necrotic core size, improved fibrous cap area, and increased vascular smooth muscle cell content within the fibrous cap. Myeloid-specific STAT4 deficiency resulted in decreased circulating neutrophils via reduced production of granulocyte-monocyte progenitors in the bone marrow. Neutrophil activation was dampened in Stat4 ^ΔLysM Ldlr ^-/- mice via reduced mitochondrial superoxide production, attenuated surface expression of degranulation marker CD63, and reduced frequency of neutrophil-platelet aggregates. Myeloid-specific STAT4 deficiency diminished expression of chemokine receptors CCR1 and CCR2 and impaired in vivo neutrophil trafficking to atherosclerotic aorta.

Conclusions

Our work indicates a pro-atherogenic role for STAT4-dependent neutrophil activation and how it contributes to multiple factors of plaque instability during advanced atherosclerosis in mice.

Moxonidine Increases Uptake of Oxidised Low-Density Lipoprotein in Cultured Vascular Smooth Muscle Cells and Inhibits Atherosclerosis in Apolipoprotein E-Deficient Mice

This study aimed to investigate the effect of the sympatholytic drug moxonidine on atherosclerosis. The effects of moxonidine on oxidised low-density lipoprotein (LDL) uptake, inflammatory gene expression and cellular migration were investigated in vitro in cultured vascular smooth muscle cells (VSMCs). The effect of moxonidine on atherosclerosis was measured by examining aortic arch Sudan IV staining and quantifying the intima-to-media ratio of the left common carotid artery in apolipoprotein E-deficient (ApoE^-/-) mice infused with angiotensin II. The levels of circulating lipid hydroperoxides in mouse plasma were measured by ferrous oxidation-xylenol orange assay. Moxonidine administration increased oxidised LDL uptake by VSMCs via activation of α2 adrenoceptors. Moxonidine increased the expression of LDL receptors and the lipid efflux transporter ABCG1. Moxonidine inhibited mRNA expression of inflammatory genes and increased VSMC migration. Moxonidine administration to ApoE^-/- mice (18 mg/kg/day) decreased atherosclerosis formation in the aortic arch and left common carotid artery, associated with increased plasma lipid hydroperoxide levels. In conclusion, moxonidine inhibited atherosclerosis in ApoE^-/- mice, which was accompanied by an increase in oxidised LDL uptake by VSMCs, VSMC migration, ABCG1 expression in VSMCs and lipid hydroperoxide levels in the plasma.