Smooth muscle cell phenotypic switching in atherosclerosis

Integrative analysis of single-Cell RNA sequencing and experimental validation in the study of abdominal aortic aneurysm progression

BACKGROUND

Abdominal aortic aneurysm (AAA) is a complex vascular disorder characterized by the progressive dilation of the abdominal aorta, with a high risk of rupture and mortality. Understanding the cellular interactions and molecular mechanisms underlying AAA development is critical for identifying potential therapeutic targets.

METHODS

This study utilized datasets GSE197748, GSE164678 and GSE183464 from the GEO database, encompassing bulk and single-cell RNA sequencing data from AAA and control samples. We performed principal component analysis, differential expression analysis, and functional enrichment analysis to identify key pathways involved in AAA. Cell-cell interactions were investigated using CellPhoneDB, focusing on fibroblasts, vascular smooth muscle cells (VSMCs), and macrophages. We further validated our findings using a mouse model of AAA induced by porcine pancreatic enzyme infusion, followed by gene expression analysis and co-immunoprecipitation experiments.

RESULTS

Our analysis revealed significant alterations in gene expression profiles between AAA and control samples, with a pronounced immune response and cell adhesion pathways being implicated. Single-cell RNA sequencing data highlighted an increased proportion of pro-inflammatory macrophages, along with changes in the composition of fibroblasts and VSMCs in AAA. CellPhoneDB analysis identified critical ligand-receptor interactions, notably collagen type I alpha 1 chain (COL1A1)/COL1A2-CD18 and thrombospondin 1 (THBS1)-CD3, suggesting complex communication networks between fibroblasts and VSMCs. In vivo experiments confirmed the upregulation of these genes in AAA mice and demonstrated the functional interaction between COL1A1/COL1A2 and CD18.

CONCLUSION

The interaction between fibroblasts and VSMCs, mediated by specific ligand-receptor pairs such as COL1A1/COL1A2-CD18 and THBS1-CD3, plays a pivotal role in AAA pathogenesis.

Circulating inflammatory proteins and abdominal aortic aneurysm: A two-sample Mendelian randomization and colocalization analyses

OBJECTIVES

Inflammatory proteins are implicated in the progression of abdominal aortic aneurysms (AAA); however, it remains debated whether they are causal or consequential. This study aimed to assess the influence of circulating inflammatory proteins on AAA via two-sample Mendelian randomization (MR) and colocalization analysis.

METHODS

Summary data on 91 circulating inflammatory protein levels were extracted from a comprehensive protein quantitative trait loci (pQTL) study involving 14,824 individuals. Genetic associations with AAA were derived from the FinnGen study (3,869 cases and 381,977 controls). MR analysis was conducted to assess the relationships between proteins and AAA risk. Colocalization analysis was employed to explore potential shared causal variants between identified proteins and AAA.

RESULTS

Using a two-sample bidirectional MR study, our findings suggested that genetically predicted elevated levels of TGFB1 (OR = 1.21, P = 0.003), SIRT2 (OR = 1.196, P = 0.031) and TNFSF14 (OR = 1.129, P = 0.034) were linked to an increased risk of AAA. Conversely, genetically predicted higher levels of CD40 (OR = 0.912, P = 0.049), IL2RB (OR = 0.839, P = 0.028) and KITLG (OR = 0.827, P = 0.008) were associated with a decreased risk of AAA. Colocalization analyses supported the association of TGFB1 and SIRT2 levels with AAA risk.

CONCLUSIONS

The proteome-wide MR and colocalization study identified TGFB1 and SIRT2 as being associated with the risk of AAA, warranting further investigation as potential therapeutic targets.

The Pathological Mechanisms and Therapeutic Molecular Targets in Arteriovenous Fistula Dysfunction

The number of patients with end-stage renal disease (ESRD) requiring hemodialysis is increasing worldwide. Although arteriovenous fistula (AVF) is the best and most important vascular access (VA) for hemodialysis, its primary maturation failure rate is as high as 60%, which seriously endangers the prognosis of hemodialysis patients. After AVF establishment, the venous outflow tract undergoes hemodynamic changes, which are translated into intracellular signaling pathway cascades, resulting in an outward and inward remodeling of the vessel wall. Outward remodeling refers to the thickening of the vessel wall and the dilation of the lumen to accommodate the high blood flow in the AVF, while inward remodeling is mainly characterized by intimal hyperplasia. More and more studies have shown that the two types of remodeling are closely related in the occurrence and development of, and jointly determining the final fate of, AVF. Therefore, it is essential to investigate the underlying mechanisms involved in outward and inward remodeling for identifying the key targets in alleviating AVF dysfunction. In this review, we summarize the current clinical diagnosis, monitoring, and treatment techniques for AVF dysfunction and discuss the possible pathological mechanisms related to improper outward and inward remodeling in AVF dysfunction, as well as summarize the similarities and differences between the two remodeling types in molecular mechanisms. Finally, the representative therapeutic targets of potential clinical values are summarized.

Epsins oversee smooth muscle cell reprograming by influencing master regulators KLF4 and OCT4

Smooth muscle cells in major arteries play a crucial role in regulating coronary artery disease. Conversion of smooth muscle cells into other adverse cell types in the artery propels the pathogenesis of the disease. Curtailing artery plaque buildup by modulating smooth muscle cell reprograming presents us a new opportunity to thwart coronary artery disease. Here, our report how Epsins, a family of endocytic adaptor proteins oversee the smooth muscle cell reprograming by influencing master regulators OCT4 and KLF4. Using single-cell RNA sequencing, we characterized the phenotype of modulated smooth muscle cells in mouse atherosclerotic plaque and found that smooth muscle cells lacking epsins undergo profound reprogramming into not only beneficial myofibroblasts but also endothelial cells for injury repair of diseased endothelium. Our work lays concrete groundwork to explore an uncharted territory as we show that depleting Epsins bolsters smooth muscle cells reprograming to endothelial cells by augmenting OCT4 activity but restrain them from reprograming to harmful foam cells by destabilizing KLF4, a master regulator of adverse reprograming of smooth muscle cells. Moreover, the expression of Epsins in smooth muscle cells positively correlates with the severity of both human and mouse coronary artery disease. Integrating our scRNA-seq data with human Genome-Wide Association Studies (GWAS) identifies pivotal roles Epsins play in smooth muscle cells in the pathological process leading to coronary artery disease. Our findings reveal a previously unexplored direction for smooth muscle cell phenotypic modulation in the development and progression of coronary artery disease and unveil Epsins and their downstream new targets as promising novel therapeutic targets for mitigating metabolic disorders.

FAK Family Kinases: A Potential Therapeutic Target for Atherosclerosis

Atherosclerosis (AS) is a chronic progressive inflammatory disease of the vascular wall and the primary pathological basis of cardiovascular and cerebrovascular disease. Focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (Pyk2), two highly homologous members of the FAK family kinases, play critical roles in integrin signaling. They also serve as scaffolding proteins that contribute to the assembly of cellular signaling complexes that regulate cell survival, cell cycle progression, and cell motility. Research indicates that the FAK family kinases is involved in the gene regulation of vascular cells and that aberrant expression of this family is associated with pathological changes in vascular disease. These findings establish the FAK family kinases as a critical signaling mediator in atherosclerotic lesions and inhibition of its activity has the potential to attenuate the pathological progression of AS. This review highlights the indispensable role of the FAK family kinases in abnormal vascular smooth muscle cell proliferation, endothelial cell dysfunction, inflammation, and lipid metabolism associated with AS. We also summarize therapeutic targets against the FAK family kinases, providing valuable insights into therapeutic strategies for AS.

Basal ATP release signals through the P2Y2 receptor to maintain the differentiated phenotype of vascular smooth muscle cells

BACKGROUND AND AIMS

Vascular smooth muscle cell (VSMC) dedifferentiation contributes substantively to vascular disease. VSMCs spontaneously release low levels of ATP that modulate vessel contractility, but it is unclear if autocrine ATP signaling in VSMCs is critical to the maintenance of the VSMC contractile phenotype.

METHODS

We used pharmacological inhibitors to block ATP release in human aortic smooth muscle cells (HASMCs) for studying changes in VSMC differentiation marker gene expression. We employed RNA interference and generated mice with SMC-specific inducible deletion of the P2Y2 receptor (P2Y2R) gene to evaluate resulting phenotypic alterations.

RESULTS

HASMCs constitutively release low levels of ATP that when blocked results in a significant decrease in VSMC differentiation marker gene expression, including smooth muscle actin (SMA), smooth muscle myosin heavy chain (SMMHC), SM-22α and calponin. Basal release of ATP represses transcriptional activation of the Krüppel-Like Factor 4 (KFL4) thereby preventing platelet-derived growth factor-BB (PDGF-BB) from inhibiting expression of SMC contractile phenotype markers. SMC-restricted conditional deletion of P2Y2R evoked dedifferentiation characterized by decreases in aortic contractility and contractile phenotype markers expression. This loss was accompanied by a transition to the synthetic phenotype with the acquisition of extracellular matrix (ECM) proteins characteristic of dedifferentiation, such as osteopontin and vimentin.

CONCLUSIONS

Our data establish the first direct evidence that an autocrine ATP release mechanism maintains SMC cytoskeletal protein expression by inhibiting VSMCs from transitioning to a synthetic phenotype, and further demonstrate that activation of the P2Y2R by basally released ATP is required for maintenance of the differentiated VSMC phenotype.

The relationship of redox signaling with the risk for atherosclerosis

Oxidative balance plays a pivotal role in physiological homeostasis, and many diseases, particularly age-related conditions, are closely associated with oxidative imbalance. While the strategic role of oxidative regulation in various diseases is well-established, the specific involvement of oxidative stress in atherosclerosis remains elusive. Atherosclerosis is a chronic inflammatory disorder characterized by plaque formation within the arteries. Alterations in the oxidative status of vascular tissues are linked to the onset, progression, and outcome of atherosclerosis. This review examines the role of redox signaling in atherosclerosis, including its impact on risk factors such as dyslipidemia, hyperglycemia, inflammation, and unhealthy lifestyle, along with dysregulation, vascular homeostasis, immune system interaction, and therapeutic considerations. Understanding redox signal transduction and the regulation of redox signaling will offer valuable insights into the pathogenesis of atherosclerosis and guide the development of novel therapeutic strategies.

Multiomics unveils extracellular vesicle-driven mechanisms of endothelial communication in human carotid atherosclerosis

Background: Carotid atherosclerosis is orchestrated by cell-cell communication that drives progression along a clinical continuum (asymptomatic to symptomatic). Extracellular vesicles (EVs) are cell-derived nanoparticles representing a new paradigm in cellular communication. Little is known about their biological cargo, cellular origin/destination, and functional roles in human atherosclerotic plaque. Methods: EVs were enriched via size exclusion chromatography from human carotid endarterectomy samples dissected into paired plaque and marginal zones (symptomatic n=16, asymptomatic n=13). EV cargos were assessed via whole transcriptome miRNA sequencing and mass spectrometry-based proteomics. EV multi-omics were integrated with bulk and single cell RNA-sequencing (scRNA-seq) datasets to predict EV cellular origin and ligand-receptor interactions, and multi-modal biological network integration of EV-cargo was completed. EV functional impact was assessed with endothelial angiogenesis assays. Results: Carotid plaques contained more EVs than adjacent marginal zones, with differential enrichment for EV-miRNAs and EV-proteins in key atherogenic pathways. EV cellular origin analysis suggested that tissue EV signatures originated from endothelial cells (EC), smooth muscle cells (SMC), and immune cells. Integrated tissue vesiculomics and scRNA-seq indicated complex EV-vascular cell communication that changed with disease progression and plaque vulnerability (i.e., symptomatic disease). Plaques from symptomatic patients, but not asymptomatic patients, were characterized by increased involvement of endothelial pathways and more complex ligand-receptor interactions, relative to their marginal zones. Plaque-EVs were predicted to mediate communication with ECs. Pathway enrichment analysis delineated an endothelial signature with roles in angiogenesis and neovascularization - well-known indices of plaque instability. This was validated functionally, wherein human carotid symptomatic plaque EVs induced sprouting angiogenesis in comparison to their matched marginal zones. Conclusion: Our findings indicate that EVs may drive dynamic changes in plaques through EV- vascular cell communication and effector functions that typify vulnerability to rupture, precipitating symptomatic disease. The discovery of endothelial-directed angiogenic processes mediated by EVs creates new therapeutic avenues for atherosclerosis.

The 9p21.3 coronary artery disease risk locus drives vascular smooth muscle cells to an osteochondrogenic state

Genome-wide association studies have identified common genetic variants at ~400 human genomic loci linked to coronary artery disease (CAD) susceptibility. Among these genomic regions, the most impactful is the 9p21.3 CAD risk locus, which spans a 60 kb gene desert and encompasses ~80 SNPs in high linkage disequilibrium. Despite nearly two decades since its discovery, the functional mechanism of this genomic region remains incompletely resolved. To investigate the transcriptional gene programs mediated by 9p21.3 risk locus, we applied a model of induced pluripotent stem cells (iPSCs) from risk and non-risk donors at 9p21.3, as well as isogenic lines with a full haplotype deletion. Upon differentiation to vascular smooth muscle cells (VSMC), single-cell transcriptomic profiling demonstrated iPSC-VSMC phenotypes resembling those from native human coronary arteries, confirming the robustness of this model. Remarkably, our analyses revealed that VSMCs harboring the 9p21.3 risk haplotype preferentially adopt an osteochondrogenic state. Importantly, we identified LIMCH1 and CRABP1 as signature genes critical for defining this transcriptional program. Our study provides new insights into the mechanism at the 9p21.3 risk locus and defines its role in driving a disease-prone transcriptional state in VSMCs.

Single-cell RNA sequencing reveals that NRF2 regulates vascular smooth muscle cell phenotypic switching in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a life-threatening disease characterized by extensive membrane destruction in the vascular wall that is closely associated with vascular smooth muscle cell (VSMC) phenotypic switching. A thorough understanding of the changes in regulatory factors during VSMC phenotypic switching is essential for managing AAA therapy. In this study, we revealed the impact of NRF2 on the modulation of VSMC phenotype and the development of AAA based on single-cell RNA sequencing analysis. By utilizing a murine model of VSMC-specific knockout of nuclear factor E2-related factor 2 (NRF2), we observed that the absence of NRF2 in VSMCs exacerbated AAA formation in an angiotensin II-induced AAA model. The downregulation of NRF2 promoted VSMC phenotypic switching, leading to an enhanced inflammatory response. Through genome-wide transcriptome analysis and loss- or gain-of-function experiments, we discovered that NRF2 upregulated the expression of VSMC contractile phenotype-specific genes by facilitating microRNA-145 (miR-145) expression. Our data identified NRF2 as a novel regulator involved in maintaining the VSMC contractile phenotype while also influencing AAA formation through an miR-145-dependent regulatory mechanism.

Coding and Non-Coding Transcriptomic Landscape of Aortic Complications in Marfan Syndrome

Marfan syndrome (MFS) is a rare congenital disorder of the connective tissue, leading to thoracic aortic aneurysms (TAA) and dissection, among other complications. Currently, the most efficient strategy to prevent life-threatening dissection is preventive surgery. Periodic imaging applying complex techniques is required to monitor TAA progression and to guide the timing of surgical intervention. Thus, there is an acute demand for non-invasive biomarkers for diagnosis and prognosis, as well as for innovative therapeutic targets of MFS. Unraveling the intricate pathomolecular mechanisms underlying the syndrome is vital to address these needs. High-throughput platforms are particularly well-suited for this purpose, as they enable the integration of different datasets, such as transcriptomic and epigenetic profiles. In this narrative review, we summarize relevant studies investigating changes in both the coding and non-coding transcriptome and epigenome in MFS-induced TAA. The collective findings highlight the implicated pathways, such as TGF-β signaling, extracellular matrix structure, inflammation, and mitochondrial dysfunction. Potential candidates as biomarkers, such as miR-200c, as well as therapeutic targets emerged, like Tfam, associated with mitochondrial respiration, or miR-632, stimulating endothelial-to-mesenchymal transition. While these discoveries are promising, rigorous and extensive validation in large patient cohorts is indispensable to confirm their clinical relevance and therapeutic potential.

Myeloid cell-derived interleukin-6 induces vascular dysfunction and vascular and systemic inflammation

Aims

The cytokine interleukin-6 (IL-6) plays a central role in the inflammation cascade as well as cardiovascular disease progression. Since myeloid cells are a primary source of IL-6 formation, we aimed to generate a mouse model to study the role of myeloid cell-derived IL-6 in vascular disease.

Methods and results

Interleukin-6-overexpressing (IL-6OE) mice were generated and crossed with LysM-Cre mice, to generate mice (LysM-IL-6OE mice) overexpressing the cytokine in myeloid cells. Eight- to 12-week-old LysM-IL-6OE mice spontaneously developed inflammatory colitis and significantly impaired endothelium-dependent aortic relaxation, increased aortic reactive oxygen species (ROS) formation, and vascular dysfunction in resistance vessels. The latter phenotype was associated with decreased survival. Vascular dysfunction was accompanied by a significant accumulation of neutrophils, monocytes, and macrophages in the aorta, increased myeloid cell reactivity (elevated ROS production), and vascular fibrosis associated with phenotypic changes in vascular smooth muscle cells. In addition to elevated Mcp1 and Cxcl1 mRNA levels, aortae from LysM-IL-6OE mice expressed higher levels of inducible NO synthase and endothelin-1, thus partially accounting for vascular dysfunction, whereas systemic blood pressure alterations were not observed. Bone marrow (BM) transplantation experiments revealed that vascular dysfunction and ROS formation were driven by BM cell-derived IL-6 in a dose-dependent manner.

Conclusion

Mice with conditional overexpression of IL-6 in myeloid cells show systemic and vascular inflammation as well as endothelial dysfunction. A decrease in circulating IL-6 levels by replacing IL-6-producing myeloid cells in the BM improved vascular dysfunction in this model, underpinning the relevant role of IL-6 in vascular disease.

Atherosclerosis Is a Smooth Muscle Cell-Driven Tumor-Like Disease

BACKGROUND

Atherosclerosis, a leading cause of cardiovascular disease, involves the pathological activation of various cell types, including immunocytes (eg, macrophages and T cells), smooth muscle cells (SMCs), and endothelial cells. Accumulating evidence suggests that transition of SMCs to other cell types, known as phenotypic switching, plays a central role in atherosclerosis development and complications. However, the characteristics of SMC-derived cells and the underlying mechanisms of SMC transition in disease pathogenesis remain poorly understood. Our objective is to characterize tumor cell-like behaviors of SMC-derived cells in atherosclerosis, with the ultimate goal of developing interventions targeting SMC transition for the prevention and treatment of atherosclerosis.

METHODS

We used SMC lineage tracing mice and human tissues and applied a range of methods, including molecular, cellular, histological, computational, human genetics, and pharmacological approaches, to investigate the features of SMC-derived cells in atherosclerosis.

RESULTS

SMC-derived cells in mouse and human atherosclerosis exhibit multiple tumor cell-like characteristics, including genomic instability, evasion of senescence, hyperproliferation, resistance to cell death, invasiveness, and activation of comprehensive cancer-associated gene regulatory networks. Specific expression of the oncogenic mutant KrasG12D in SMCs accelerates phenotypic switching and exacerbates atherosclerosis. Furthermore, we provide proof of concept that niraparib, an anticancer drug targeting DNA damage repair, attenuates atherosclerosis progression and induces regression of lesions in advanced disease in mouse models.

CONCLUSIONS

Our findings demonstrate that atherosclerosis is an SMC-driven tumor-like disease, advancing our understanding of its pathogenesis and opening prospects for innovative precision molecular strategies aimed at preventing and treating atherosclerotic cardiovascular disease.

Genetic influence on vascular smooth muscle cell apoptosis

Vascular smooth muscle cell (VSMC) proliferation, migration, and apoptosis play important roles in many physiological processes and pathological conditions. To identify genetic influences on VSMC behavior, we measured these traits and undertook genome-wide association studies in primary umbilical artery-derived VSMCs from >2000 individuals. Although there were no genome-wide significant associations for VSMC proliferation or migration, genetic variants at two genomic loci (7p15.3 and 7q32.3) showed highly significant associations with VSMC apoptosis (P = 1.95 × 10-13 and P = 7.47 × 10-9, respectively). The lead variant at the 7p51.3 locus was associated with increased expression of the GSDME and PALS2 genes in VSMCs. Knockdown of GSDME or PALS2 in VSMCs attenuated apoptotic cell death. A protein co-immunoprecipitation assay indicated that GSDME complexed with PALS2. PALS2 knockdown attenuated activated caspase-3 and GSDME fragmentation, whilst GSDME knockdown also reduced activated caspase-3. These findings provide new insights into the genetic regulation of VSMC apoptosis, with potential utility for therapeutic development.

Small nucleolar RNA host gene 18 controls vascular smooth muscle cell contractile phenotype and neointimal hyperplasia

AIMS

Long non-coding RNA (LncRNA) small nucleolar RNA host gene 18 (SNHG18) has been widely implicated in cancers. However, little is known about its functional involvement in vascular diseases. Herein, we attempted to explore a role for SNHG18 in modulating vascular smooth muscle cell (VSMC) contractile phenotype and injury-induced neointima formation.

METHODS AND RESULTS

Analysis of single-cell RNA sequencing and transcriptomic datasets showed decreased levels of SNHG18 in injured and atherosclerotic murine and human arteries, which is positively associated with VSMC contractile genes. SNHG18 was upregulated in VSMCs by TGFβ1 through transcription factors Sp1 and SMAD3. SNHG18 gene gain/loss-of-function studies revealed that VSMC contractile phenotype was positively regulated by SNHG18. Mechanistic studies showed that SNHG18 promotes a contractile VSMC phenotype by up-regulating miR-22-3p. SNHG18 up-regulates miR-22 biogenesis and miR-22-3p production by competitive binding with the A-to-I RNA editing enzyme, adenosine deaminase acting on RNA-2 (ADAR2). Surprisingly, we observed that ADAR2 inhibited miR-22 biogenesis not through increasing A-to-I editing within primary miR-22, but by interfering with the binding of microprocessor complex subunit DGCR8 to primary miR-22. Importantly, perivascular SNHG18 overexpression in the injured vessels dramatically up-regulated the expression levels of miR-22-3p and VSMC contractile genes, and prevented injury-induced neointimal hyperplasia. Such modulatory effects were reverted by miR-22-3p inhibition in the injured arteries. Finally, we observed a similar regulator role for SNHG18 in human VSMCs and a decreased expression level of both SNHG18 and miR-22-3p in diseased human arteries; and we found that the expression level of SNHG18 was positively associated with that of miR-22-3p in both healthy and diseased human arteries.

CONCLUSION

We demonstrate that SNHG18 is a novel regulator in governing VSMC contractile phenotype and preventing injury-induced neointimal hyperplasia. Our findings have important implications for therapeutic targeting snhg18/miR-22-3p signalling in vascular diseases.

Deciphering smooth muscle cell heterogeneity in atherosclerotic plaques and constructing model: a multi-omics approach with focus on KLF15/IGFBP4 axis

BACKGROUND

Ruptured atherosclerotic plaques often precipitate severe ischemic events, such as stroke and myocardial infarction. Unraveling the intricate molecular mechanisms governing vascular smooth muscle cell (VSMC) behavior in plaque stabilization remains a formidable challenge.

METHODS

In this study, we leveraged single-cell and transcriptomic datasets from atherosclerotic plaques retrieved from the gene expression omnibus (GEO) database. Employing a combination of single-cell population differential analysis, weighted gene co-expression network analysis (WGCNA), and transcriptome differential analysis techniques, we identified specific genes steering the transformation of VSMCs in atherosclerotic plaques. Diagnostic models were developed and validated through gene intersection, utilizing the least absolute shrinkage and selection operator (LASSO) and random forest (RF) methods. Nomograms for plaque assessment were constructed. Tissue localization and expression validation were performed on specimens from animal models, utilizing immunofluorescence co-localization, western blot, and reverse-transcription quantitative-polymerase chain reaction (RT-qPCR). Various online databases were harnessed to predict transcription factors (TFs) and their interacting compounds, with determination of the cell-specific localization of TF expression using single-cell data.

RESULTS

Following rigorous quality control procedures, we obtained a total of 40,953 cells, with 6,261 representing VSMCs. The VSMC population was subsequently clustered into 5 distinct subpopulations. Analyzing inter-subpopulation cellular communication, we focused on the SMC2 and SMC5 subpopulations. Single-cell subpopulation and WGCNA analyses revealed significant module enrichments, notably in collagen-containing extracellular matrix and cell-substrate junctions. Insulin-like growth factor binding protein 4 (IGFBP4), apolipoprotein E (APOE), and cathepsin C (CTSC) were identified as potential diagnostic markers for early and advanced plaques. Notably, gene expression pattern analysis suggested that IGFBP4 might serve as a protective gene, a hypothesis validated through tissue localization and expression analysis. Finally, we predicted TFs capable of binding to IGFBP4, with Krüppel-like family 15 (KLF15) emerging as a prominent candidate showing relative specificity within smooth muscle cells. Predictions about compounds associated with affecting KLF15 expression were also made.

CONCLUSION

Our study established a plaque diagnostic and assessment model and analyzed the molecular interaction mechanisms of smooth muscle cells within plaques. Further analysis revealed that the transcription factor KLF15 may regulate the biological behaviors of smooth muscle cells through the KLF15/IGFBP4 axis, thereby influencing the stability of advanced plaques via modulation of the PI3K-AKT signaling pathway. This could potentially serve as a target for plaque stability assessment and therapy, thus driving advancements in the management and treatment of atherosclerotic plaques.

Somatic PDGFRB activating variants promote smooth muscle cell phenotype modulation in intracranial fusiform aneurysm

BACKGROUND

The fusiform aneurysm is a nonsaccular dilatation affecting the entire vessel wall over a short distance. Although PDGFRB somatic variants have been identified in fusiform intracranial aneurysms, the molecular and cellular mechanisms driving fusiform intracranial aneurysms due to PDGFRB somatic variants remain poorly understood.

METHODS

In this study, single-cell sequencing and immunofluorescence were employed to investigate the phenotypic changes in smooth muscle cells within fusiform intracranial aneurysms. Whole-exome sequencing revealed the presence of PDGFRB gene mutations in fusiform intracranial aneurysms. Subsequent immunoprecipitation experiments further explored the functional alterations of these mutated PDGFRB proteins. For the common c.1684 mutation site of PDGFRβ, we established mutant smooth muscle cell lines and zebrafish models. These models allowed us to simulate the effects of PDGFRB mutations. We explored the major downstream cellular pathways affected by PDGFRBY562D mutations and evaluated the potential therapeutic effects of Ruxolitinib.

RESULTS

Single-cell sequencing of two fusiform intracranial aneurysms sample revealed downregulated smooth muscle cell markers and overexpression of inflammation-related markers in vascular smooth muscle cells, which was validated by immunofluorescence staining, indicating smooth muscle cell phenotype modulation is involved in fusiform aneurysm. Whole-exome sequencing was performed on seven intracranial aneurysms (six fusiform and one saccular) and PDGFRB somatic mutations were detected in four fusiform aneurysms. Laser microdissection and Sanger sequencing results indicated that the PDGFRB mutations were present in smooth muscle layer. For the c.1684 (chr5: 149505131) site mutation reported many times, further cell experiments showed that PDGFRBY562D mutations promoted inflammatory-related vascular smooth muscle cell phenotype and JAK-STAT pathway played a crucial role in the process. Notably, transfection of PDGFRBY562D in zebrafish embryos resulted in cerebral vascular anomalies. Ruxolitinib, the JAK inhibitor, could reversed the smooth muscle cells phenotype modulation in vitro and inhibit the vascular anomalies in zebrafish induced by PDGFRB mutation.

CONCLUSION

Our findings suggested that PDGFRB somatic variants played a role in regulating smooth muscle cells phenotype modulation in fusiform aneurysms and offered a potential therapeutic option for fusiform aneurysms.

Long non-coding RNAs H19 and NKILA are associated with the risk of death and lacunar stroke in the elderly population

INTRODUCTION

Differential expression of long non-coding RNAs (lncRNAs) is a hallmark of cardiovascular aging, cerebrovascular diseases, and neurodegenerative disorders. This research article investigates the association between a panel of lncRNAs and the risk of death and ischemic stroke in a cohort of non-institutionalized elderly subjects.

METHOD

A total of 361 healthy individuals aged 75 years old, prospectively recruited in the Vienna Transdanube Aging (VITA) cohort, were included. Expression of lncRNAs at baseline was assessed using quantitative polymerase chain reaction PCR with pre-amplification reaction, using 18S for normalization. The primary endpoint was all-cause mortality; the secondary endpoint was the incidence of new ischemic brain lesions. Death was assessed over a 14-year follow-up, and ischemic brain lesions were evaluated by magnetic resonance imaging (MRI) over a 90-month follow-up. Ischemic brain lesions were divided into large brain infarcts (Ø≥ 1.5 cm) or lacunes (Ø< 1.5 cm) RESULTS: The primary endpoint occurred in 53.5 % of the study population. The incidence of the secondary endpoint was 16 %, with a 3.3 % being large brain infarcts, and a 12.7 % lacunes. After adjustment for potential confounders, the lncRNA H19 predicted the incidence of the primary endpoint (HR 1.194, 95 % C.I. 1.012-1.409, p = 0.036), whereas the lncRNA NKILA was associated with lacunar stroke (HR 0.571, 95 % C.I. 0.375-0.868, p = 0.006).

CONCLUSION

In a prospective cohort of non-institutionalized elderly subjects, high levels of lncRNA H19 are associated with a higher risk of death, while low levels of lncRNA NKILA predict an increased risk of lacunar stroke.

Ovariectomy-Induced Arterial Stiffening Differs From Vascular Aging and Is Reversed by GPER Activation

BACKGROUND

Arterial stiffness is a cardiovascular risk factor and dramatically increases as women transition through menopause. The current study assessed whether a mouse model of menopause increases arterial stiffness in a similar manner to aging and whether activation of the G-protein-coupled estrogen receptor could reverse stiffness.

METHODS

Female C57Bl/6J mice were ovariectomized at 10 weeks of age or aged to 52 weeks, and some mice were treated with G-protein-coupled estrogen receptor agonists.

RESULTS

Ovariectomy and aging increased pulse wave velocity to a similar extent independent of changes in blood pressure. Aging increased carotid wall thickness, while ovariectomy increased material stiffness without altering vascular geometry. RNA-sequencing analysis revealed that ovariectomy downregulated smooth muscle contractile genes. The enantiomerically pure G-protein-coupled estrogen receptor agonist, LNS8801, reversed stiffness in ovariectomy mice to a greater degree than the racemic agonist G-1. In summary, ovariectomy and aging induced arterial stiffening via potentially different mechanisms. Aging was associated with inward remodeling, while ovariectomy-induced material stiffness independent of geometry and a loss of the contractile phenotype.

CONCLUSIONS

This study enhances our understanding of the impact of estrogen loss on vascular health in a murine model and warrants further studies to examine the ability of LNS8801 to improve vascular health in menopausal women.

Development and performance evaluation of a novel elastic bacterial nanocellulose/polyurethane small caliber artificial blood vessels

There is an increasing demand for small-diameter blood vessels. Currently, there is no clinically available small-diameter artificial vessel. Bacterial nanocellulose (BNC) has vast potential for applications in artificial blood vessels due to its good biocompatibility. At the same time, medical polyurethane (PU) is a highly elastic polymer material widely used in artificial blood vessels. This study reports a composite small-diameter BNC/PU conduit using a non-solvent-induced phase separation method with the highly hydrophilic BNC tube as the skeleton and the hydrophobic polycarbonate PU as the filling material. The results revealed that the compliance and mechanical matching of BNC/PU tubes were higher than BNC tubes; the axial/radial mechanical strength, burst pressure, and suture strength were significantly improved; the blood compatibility and cell compatibility were also excellent. The molecular and subcutaneous embedding tests showed that the composite tubes had lighter inflammatory reactions. The results of the animal substitution experiments showed that the BNC/PU tubes kept blood flow unobstructed without tissue proliferation after implantation in rats for 9 months. Thus, the BNC/PU small-diameter vascular prosthesis had the potential for long-term patency and acted as an ideal material for small-diameter vessels.

GLP-1 receptor agonists and atherosclerosis protection: the vascular endothelium takes center stage

Atherosclerotic cardiovascular disease is a chronic condition that often copresents with type 2 diabetes and obesity. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are incretin mimetics endorsed by major professional societies for improving glycemic status and reducing atherosclerotic risk in people living with type 2 diabetes. Although the cardioprotective efficacy of GLP-1RAs and their relationship with traditional risk factors are well established, there is a paucity of publications that have summarized the potentially direct mechanisms through which GLP-1RAs mitigate atherosclerosis. This review aims to narrow this gap by providing comprehensive and in-depth mechanistic insight into the antiatherosclerotic properties of GLP-1RAs demonstrated across large outcome trials. Herein, we describe the landmark cardiovascular outcome trials that triggered widespread excitement around GLP-1RAs as a modern class of cardioprotective agents, followed by a summary of the origins of GLP-1RAs and their mechanisms of action. The effects of GLP-1RAs at each major pathophysiological milestone of atherosclerosis, as observed across clinical trials, animal models, and cell culture studies, are described in detail. Specifically, this review provides recent preclinical and clinical evidence that suggest GLP-1RAs preserve vessel health in part by preventing endothelial dysfunction, achieved primarily through the promotion of angiogenesis and inhibition of oxidative stress. These protective effects are in addition to the broad range of atherosclerotic processes GLP-1RAs target downstream of endothelial dysfunction, which include systemic inflammation, monocyte recruitment, proinflammatory macrophage and foam cell formation, vascular smooth muscle cell proliferation, and plaque development.

The role of transcription factors in the pathogenesis and therapeutic targeting of vascular diseases

Transcription factors (TFs) constitute an essential component of epigenetic regulation. They contribute to the progression of vascular diseases by regulating epigenetic gene expression in several vascular diseases. Recently, numerous regulatory mechanisms related to vascular pathology, ranging from general TFs that are continuously activated to histiocyte-specific TFs that are activated under specific circumstances, have been studied. TFs participate in the progression of vascular-related diseases by epigenetically regulating vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs). The Krüppel-like family (KLF) TF family is widely recognized as the foremost regulator of vascular diseases. KLF11 prevents aneurysm progression by inhibiting the apoptosis of VSMCs and enhancing their contractile function. The presence of KLF4, another crucial member, suppresses the progression of atherosclerosis (AS) and pulmonary hypertension by attenuating the formation of VSMCs-derived foam cells, ameliorating endothelial dysfunction, and inducing vasodilatory effects. However, the mechanism underlying the regulation of the progression of vascular-related diseases by TFs has remained elusive. The present study categorized the TFs involved in vascular diseases and their regulatory mechanisms to shed light on the potential pathogenesis of vascular diseases, and provide novel insights into their diagnosis and treatment.

Interstitial Fluid Shear Stress Induces the Synthetic Phenotype Switching of VSMCs to Release Pro-calcified Extracellular Vesicles via EGFR-MAPK-KLF5 Pathway

Phenotypic switching (from contractile to synthetic) of vascular smooth muscle cells (VSMCs) is essential in the progression of atherosclerosis. The damaged endothelium in the atherosclerotic artery exposes VSMCs to increased interstitial fluid shear stress (IFSS). However, the precise mechanisms by which increased IFSS influences VSMCs phenotypic switching are unrevealed. Here, we employed advanced numerical simulations to calculate IFSS values accurately based on parameters acquired from patient samples. We then carefully investigated the phenotypic switching and extracellular vesicles (EVs) secretion of VSMCs under various IFSS conditions. By employing a comprehensive set of approaches, we found that VSMCs exhibited synthetic phenotype upon atherosclerotic IFSS. This synthetic phenotype is the upstream regulator for the enhanced secretion of pro-calcified EVs. Mechanistically, as a mechanotransducer, the epidermal growth factor receptor (EGFR) initiates the flow-based mechanical cues to MAPK signaling pathway, facilitating the nuclear accumulation of the transcription factor krüppel-like factor 5 (KLF5). Furthermore, pharmacological inhibiting either EGFR or MAPK signaling pathway blocks the nuclear accumulation of KLF5 and finally results in the maintenance of contractile VSMCs even under increased IFSS stimulation. Collectively, targeting this signaling pathway holds potential as a novel therapeutic strategy to inhibit VSMCs phenotypic switching and mitigate the progression of atherosclerosis.

NKX2-5 regulates vessel remodeling in scleroderma-associated pulmonary arterial hypertension

NKX2-5 is a member of the homeobox-containing transcription factors critical in regulating tissue differentiation in development. Here, we report a role for NKX2-5 in vascular smooth muscle cell phenotypic modulation in vitro and in vascular remodeling in vivo. NKX2-5 is upregulated in scleroderma patients with pulmonary arterial hypertension. Suppression of NKX2-5 expression in smooth muscle cells halted vascular smooth muscle proliferation and migration, enhanced contractility, and blocked the expression of extracellular matrix genes. Conversely, overexpression of NKX2-5 suppressed the expression of contractile genes (ACTA2, TAGLN, CNN1) and enhanced the expression of matrix genes (COL1) in vascular smooth muscle cells. In vivo, conditional deletion of NKX2-5 attenuated blood vessel remodeling and halted the progression to hypertension in a mouse chronic hypoxia model. This study revealed that signals related to injury such as serum and low confluence, which induce NKX2-5 expression in cultured cells, is potentiated by TGF-β and further enhanced by hypoxia. The effect of TGF-β was sensitive to ERK5 and PI3K inhibition. Our data suggest a pivotal role for NKX2-5 in the phenotypic modulation of smooth muscle cells during pathological vascular remodeling and provide proof of concept for therapeutic targeting of NKX2-5 in vasculopathies.

miR-200a-3p inhibits the PDGF-BB-induced proliferation of VSMCs by affecting their phenotype-associated proteins

Accumulating evidence shows that the abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) can significantly affect the long-term prognosis of coronary artery bypass grafting. This study aimed to explore the factors affecting the proliferation, migration, and phenotypic transformation of VSMCs. First, we stimulated VSMCs with different platelet-derived growth factor-BB (PDGF-BB) concentrations, analyzed the expression of phenotype-associated proteins by Western blotting, and examined cell proliferation by scratch wound healing and the 5-ethynyl-2-deoxyuridine (EdU) assay. VSMC proliferation was induced most by PDGF-BB treatment at 20 ng/mL. miR-200a-3p decreased significantly in A7r5 cells stimulated with PDGF-BB. The overexpression of miR-200a-3p reversed the downregulation of α-SMA (p < 0.001) and the upregulation of vimentin (p < 0.001) caused by PDGF-BB. CCK8 and EdU analyses showed that miR-200a-3p overexpression could inhibit PDGF-BB-induced cell proliferation (p < 0.001). However, flow cytometric analysis showed that it did not significantly increase cell apoptosis. Collectively, the overexpression of miR-200a-3p inhibited the proliferation and migration of VSMCs induced by PDGF-BB, partly by affecting phenotypic transformation-related proteins, providing a new strategy for relieving the restenosis of vein grafts.

Secreted Protein Profiling of Human Aortic Smooth Muscle Cells Identifies Vascular Disease Associations

BACKGROUND

Smooth muscle cells (SMCs), which make up the medial layer of arteries, are key cell types involved in cardiovascular disease, the leading cause of mortality and morbidity worldwide. In response to microenvironment alterations, SMCs dedifferentiate from a contractile to a synthetic phenotype characterized by an increased proliferation, migration, production of ECM (extracellular matrix) components, and decreased expression of SMC-specific contractile markers. These phenotypic changes result in vascular remodeling and contribute to the pathogenesis of cardiovascular disease, including coronary artery disease, stroke, hypertension, and aortic aneurysms. Here, we aim to identify the genetic variants that regulate ECM secretion in SMCs and predict the causal proteins associated with vascular disease-related loci identified in genome-wide association studies.

METHODS

Using human aortic SMCs from 123 multiancestry healthy heart transplant donors, we collected the serum-free media in which the cells were cultured for 24 hours and conducted liquid chromatography-tandem mass spectrometry-based proteomic analysis of the conditioned media.

RESULTS

We measured the abundance of 270 ECM and related proteins. Next, we performed protein quantitative trait locus mapping and identified 20 loci associated with secreted protein abundance in SMCs. We functionally annotated these loci using a colocalization approach. This approach prioritized the genetic variant rs6739323-A at the 2p22.3 locus, which is associated with lower expression of LTBP1 (latent-transforming growth factor beta-binding protein 1) in SMCs and atherosclerosis-prone areas of the aorta, and increased risk for SMC calcification. We found that LTBP1 expression is abundant in SMCs, and its expression at mRNA and protein levels was reduced in unstable and advanced atherosclerotic plaque lesions.

CONCLUSIONS

Our results unravel the SMC proteome signature associated with vascular disorders, which may help identify potential therapeutic targets to accelerate the pathway to translation.

Cardiovascular Mechano-Epigenetics: Force-Dependent Regulation of Histone Modifications and Gene Regulation

The local mechanical microenvironment impacts on the cell behavior. In the cardiovascular system, cells in both the heart and the vessels are exposed to continuous blood flow, blood pressure, stretching forces, and changing extracellular matrix stiffness. The force-induced signals travel all the way to the nucleus regulating epigenetic changes such as chromatin dynamics and gene expression. Mechanical cues are needed at the very early stage for a faultless embryological development, while later in life, aberrant mechanical signaling can lead to a range of pathologies, including diverse cardiovascular diseases. Hence, an investigation of force-generated epigenetic alteration at different time scales is needed to understand fully the phenotypic changes in disease onset and progression. That being so, cardiovascular mechano-epigenetics emerges as an attractive field of study. Given the rapid advances in this emergent field of research, this short review aims to provide an analysis of the state of knowledge of force-induced epigenetic changes in the cardiovascular field.

CircTLK1: A novel regulator involved in VSMC phenotypic switching and the developmental process of atherosclerosis

Phenotypic switching of vascular smooth muscle cells (VSMCs) is essential for atherosclerosis development. Circular RNA (circRNA) is a specific non-coding RNA that is produced as a closed-loop structure in mammals, and its specific expression pattern is closely related to its cell type and tissue. To clarify the roles of circTLK1 in VSMC phenotypic switching, we performed qRT-PCR, immunoblotting, and immunostaining. qRT-PCR revealed that circTLK1 was upregulated in both mouse models of atherosclerosis in vivo and PDGF (platelet-derived growth factor)-BB-induced VSMCs in vitro. Furthermore, the overexpression of circTLK1 promoted PDGF-BB-induced VSMC phenotypic switching. Conversely, experiments performed in vivo demonstrate that the knockdown of SMC-specific circTLK1 led to a reduction in the development of atherosclerosis. The relationship between circTLK1 and miR-513a-3p and Krüppel-like factor 4 (KLF4) was detected by RNA immunoprecipitation (RIP), luciferase reporter assay, RNA pull-down, and RNA fluorescence in situ hybridization (RNA FISH). Mechanistically, circTLK1 acted as a sponge for miR-513a-3p, leading to the upregulation of KLF4, a key transcription factor for phenotypic switching. Targeting the circTLK1/miR-513a-3p/KLF4 axis may provide a potential therapeutic strategy for atherosclerosis.

PCSK9 stimulates Syk, PKCδ, and NF-κB, leading to atherosclerosis progression independently of LDL receptor

Proprotein convertase subtilisin/kexin type-9 (PCSK9) binds to and degrades low-density lipoprotein (LDL) receptor, leading to increase of LDL cholesterol in blood. Its blockers have emerged as promising therapeutics for cardiovascular diseases. Here we show that PCSK9 itself directly induces inflammation and aggravates atherosclerosis independently of the LDL receptor. PCSK9 exacerbates atherosclerosis in LDL receptor knockout mice. Adenylyl cyclase-associated protein 1 (CAP1) is the main binding partner of PCSK9 and indispensable for the inflammatory action of PCSK9, including induction of cytokines, Toll like receptor 4, and scavenger receptors, enhancing the uptake of oxidized LDL. We find spleen tyrosine kinase (Syk) and protein kinase C delta (PKCδ) to be the key mediators of inflammation after PCSK9-CAP1 binding. In human peripheral blood mononuclear cells, serum PCSK9 levels are positively correlated with Syk, PKCδ, and p65 phosphorylation. The CAP1-fragment crystallizable region (CAP1-Fc) mitigates PCSK9-mediated inflammatory signal transduction more than the PCSK9 blocking antibody evolocumab does.

Transcription Factor 21: A Transcription Factor That Plays an Important Role in Cardiovascular Disease

BACKGROUND

According to the World Health Organisation's Health Report 2019, approximately 17.18 million people die from cardiovascular disease each year, accounting for more than 30% of all global deaths. Therefore, the occurrence of cardiovascular disease is still a global concern. The transcription factor 21 (TCF21) plays an important role in cardiovascular diseases. This article reviews the regulation mechanism of TCF21 expression and activity and focuses on its important role in atherosclerosis in order to contribute to the development of diagnosis and treatment of cardiovascular diseases.

SUMMARY

TCF21 is involved in the phenotypic regulation of vascular smooth muscle cells (VSMCs), promotes the proliferation and migration of VSMCs, and participates in the activation of inflammatory sequences. Increased proliferation and migration of VSMCs can lead to neointimal hyperplasia after vascular injury. Abnormal hyperplasia of neointima and inflammation are one of the main features of atherosclerosis. Therefore, targeting TCF21 may become a potential treatment for relieving atherosclerosis.

KEY MESSAGES

TCF21 as a member of basic helix-loop-helix transcription factors regulates cell growth and differentiation by modulating gene expression during the development of different organs and plays an important role in cardiovascular development and disease. VSMCs and cells derived from VSMCs constitute the majority of plaques in atherosclerosis. TCF21 plays a key role in regulation of VSMCs' phenotype, thus accelerating atherogenesis in the early stage. However, TCF21 enhances plaque stability in late-stage atherosclerosis. The dual role of TCF21 should be considered in the translational medicine.

Saponins as therapeutic candidates for atherosclerosis

Drug development for atherosclerosis, the underlying pathological state of ischemic cardiovascular diseases, has posed a longstanding challenge. Saponins, classified as steroid or triterpenoid glycosides, have shown promising therapeutic potential in the treatment of atherosclerosis. Through an exhaustive examination of scientific literature spanning from May 2013 to May 2023, we identified 82 references evaluating 37 types of saponins in terms of their prospective impacts on atherosclerosis. These studies suggest that saponins have the potential to ameliorate atherosclerosis by regulating lipid metabolism, inhibiting inflammation, suppressing apoptosis, reducing oxidative stress, and modulating smooth muscle cell proliferation and migration, as well as regulating gut microbiota, autophagy, endothelial senescence, and angiogenesis. Notably, ginsenosides exhibit significant potential and manifest essential pharmacological attributes, including lipid-lowering, anti-inflammatory, anti-apoptotic, and anti-oxidative stress effects. This review provides a comprehensive examination of the pharmacological attributes of saponins in atherosclerosis, with particular emphasis on their role in the regulation of lipid metabolism regulation and anti-inflammatory effects. Thus, saponins may warrant further investigation as a potential therapy for atherosclerosis. However, due to various reasons such as low oral bioavailability, the clinical application of saponins in the treatment of atherosclerosis still needs further exploration.

Inhibition of miR-33a-5p in Macrophage-like Cells In Vitro Promotes apoAI-Mediated Cholesterol Efflux

Atherosclerosis is caused by cholesterol accumulation within arteries. The intima is where atherosclerotic plaque accumulates and where lipid-laden foam cells reside. Intimal foam cells comprise of both monocyte-derived macrophages and macrophage-like cells (MLC) of vascular smooth muscle cell (VSMC) origin. Foam cells can remove cholesterol via apoAI-mediated cholesterol efflux and this process is regulated by the transporter ABCA1. The microRNA miR-33a-5p is thought to be atherogenic via silencing ABCA1 which promotes cholesterol retention and data has shown inhibiting miR-33a-5p in macrophages may be atheroprotective via enhancing apoAI-mediated cholesterol efflux. However, it is not entirely elucidated whether precisely inhibiting miR-33a-5p in MLC also increases ABCA1-dependent cholesterol efflux. Therefore, the purpose of this work is to test the hypothesis that inhibition of miR-33a-5p in cultured MLC enhances apoAI-mediated cholesterol efflux. In our study, we utilized the VSMC line MOVAS cells in our experiments, and cholesterol-loaded MOVAS cells to convert this cell line into MLC. Inhibition of miR-33a-5p was accomplished by transducing cells with a lentivirus that expresses an antagomiR directed at miR-33a-5p. Expression of miR-33a-5p was analyzed by qRT-PCR, ABCA1 protein expression was assessed via immunoblotting, and apoAI-mediated cholesterol efflux was measured using cholesterol efflux assays. In our results, we demonstrated that lentiviral vector-mediated knockdown of miR-33a-5p resulted in decreasing expression of this microRNA in cultured MLC. Moreover, reduction of miR-33a-5p in cultured MLC resulted in de-repression of ABCA1 expression, which caused ABCA1 protein upregulation in cultured MLC. Additionally, this increase in ABCA1 protein expression resulted in enhancing ABCA1-dependent cholesterol efflux through increasing apoAI-mediated cholesterol efflux in cultured MLC. From these findings, we conclude that inhibiting miR-33a-5p in MLC may protect against atherosclerosis by promoting ABCA1-dependent cholesterol efflux.

Consensus statement-graft treatment in cardiovascular bypass graft surgery

Coronary artery bypass grafting (CABG) is and continues to be the preferred revascularization strategy in patients with multivessel disease. Graft selection has been shown to influence the outcomes following CABG. During the last almost 60 years saphenous vein grafts (SVG) together with the internal mammary artery have become the standard of care for patients undergoing CABG surgery. While there is little doubt about the benefits, the patency rates are constantly under debate. Despite its acknowledged limitations in terms of long-term patency due to intimal hyperplasia, the saphenous vein is still the most often used graft. Although reendothelialization occurs early postoperatively, the process of intimal hyperplasia remains irreversible. This is due in part to the persistence of high shear forces, the chronic localized inflammatory response, and the partial dysfunctionality of the regenerated endothelium. "No-Touch" harvesting techniques, specific storage solutions, pressure controlled graft flushing and external stenting are important and established methods aiming to overcome the process of intimal hyperplasia at different time levels. Still despite the known evidence these methods are not standard everywhere. The use of arterial grafts is another strategy to address the inferior SVG patency rates and to perform CABG with total arterial revascularization. Composite grafting, pharmacological agents as well as latest minimal invasive techniques aim in the same direction. To give guide and set standards all graft related topics for CABG are presented in this expert opinion document on graft treatment.

SM22α deficiency: promoting vascular fibrosis via SRF-SMAD3-mediated activation of Col1a2 transcription following arterial injury

Vascular fibrosis, characterized by increased Type I collagen expression, significantly contributes to vascular remodeling. Our previous studies show that disrupting the expression of SM22α (aka SM22, Tagln) induces extensive vascular remodeling following arterial injury, involving oxidative stress, inflammation, and chondrogenesis within the vessel wall. This study aims to investigate the molecular mechanisms underlying the transcription of Col1a2 , a key fibrotic extracellular matrix marker. We observed upregulation of COL1A2 in the arterial wall of Sm22 -/- mice following carotid injury. Bioinformatics and molecular analyses reveal that Col1a2 transcription depends on a CArG box in the promoter, activated synergistically by SRF and SMAD3. Notably, we detected enhanced nuclear translocation of both SRF and SMAD3 in the smooth muscle cells of the injured carotid artery in Sm22 -/- mice. These findings demonstrate that SM22 deficiency regulates vascular fibrosis through the interaction of SRF and the SMAD3-mediated canonical TGF-β1 signal pathway, suggesting SM22α as a potential therapeutic target for preventing vascular fibrosis.

Navigating the landscape: Prospects and hurdles in targeting vascular smooth muscle cells for atherosclerosis diagnosis and therapy

Vascular smooth muscle cells (VSMCs) have emerged as pivotal contributors throughout all phases of atherosclerotic plaque development, effectively dispelling prior underestimations of their prevalence and significance. Recent lineage tracing studies have unveiled the clonal nature and remarkable adaptability inherent to VSMCs, thereby illuminating their intricate and multifaceted roles in the context of atherosclerosis. This comprehensive review provides an in-depth exploration of the intricate mechanisms and distinctive characteristics that define VSMCs across various physiological processes, firmly underscoring their paramount importance in shaping the course of atherosclerosis. Furthermore, this review offers a thorough examination of the significant strides made over the past two decades in advancing imaging techniques and therapeutic strategies with a precise focus on targeting VSMCs within atherosclerotic plaques, notably spotlighting meticulously engineered nanoparticles as a promising avenue. We envision the potential of VSMC-targeted nanoparticles, thoughtfully loaded with medications or combination therapies, to effectively mitigate pro-atherogenic VSMC processes. These advancements are poised to contribute significantly to the pivotal objective of modulating VSMC phenotypes and enhancing plaque stability. Moreover, our paper also delves into recent breakthroughs in VSMC-targeted imaging technologies, showcasing their remarkable precision in locating microcalcifications, dynamically monitoring plaque fibrous cap integrity, and assessing the therapeutic efficacy of medical interventions. Lastly, we conscientiously explore the opportunities and challenges inherent in this innovative approach, providing a holistic perspective on the potential of VSMC-targeted strategies in the evolving landscape of atherosclerosis research and treatment.

Re-analysis of single-cell transcriptomics reveals a critical role of macrophage-like smooth muscle cells in advanced atherosclerotic plaque

Aims: Smooth muscle cell (SMC) remodeling poses a critical feature in the development and progression of atherosclerosis. Although fate mapping and in silicon approaches have expanded SMC phenotypes in atherosclerosis, it still remains elusive about the contributions of individual SMC phenotypes and molecular dynamics to advanced atherosclerotic plaque. Methods: Using single-cell transcriptome, we investigated cellular compositions of human carotid plaque laden with atherosclerotic core, followed by in vivo experiments utilizing SMC-lineage tracing technology, bulk RNA sequencing (RNA-seq) and both in vivo and in vitro validation of the underlying molecular mechanism. Results: 5 functionally distinct SMC subtypes were uncovered based on transcriptional features (described as contractile, fibroblast-like, osteogenic, synthetic and macrophage-like) within the niche. A proinflammatory, macrophage-like SMC subtype displaying an intermediary phenotype between SMC and macrophage, exhibits prominent potential in destabilizing plaque. At the molecular level, we explored cluster-specific master regulons by algorithm, and identified interferon regulatory factor-8 (IRF8) as a potential stimulator of SMC-to-macrophage transdifferentiation via activating nuclear factor-κB (NF-κB) signaling. Conclusions: Our study illustrates a comprehensive cell atlas and molecular landscape of advanced atherosclerotic lesion, which might renovate current understanding of SMC biology in atherosclerosis.

Techniques and Technologies to Improve Vein Graft Patency in Coronary Surgery

Vein grafts are the most used conduits in coronary artery bypass grafting (CABG), even though many studies have suggested their lower patency compared to arterial alternatives. We have reviewed the techniques and technologies that have been investigated over the years with the aim of improving the quality of these conduits. We found that preoperative and postoperative optimal medical therapy and no-touch harvesting techniques have the strongest evidence for optimizing vein graft patency. On the other hand, the use of venous external support, endoscopic harvesting, vein preservation solution and anastomosis, and graft configuration need further investigation. We have also analyzed strategies to treat vein graft failure: when feasible, re-doing the CABG and native vessel primary coronary intervention (PCI) are the best options, followed by percutaneous procedures targeting the failed grafts.

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.

The protective effects of empagliflozin on DNA oxidative changes in a model of vascular endothelial and smooth muscle cells damaged by oxidized cholesterol

BACKGROUND

Diabetes patients often suffer chronic vascular complications resulting from endothelial dysfunction, smooth muscle cell (SMC) proliferation, inflammation and disturbed oxidative balance. Empagliflozin is one of three approved sodium-glucose cotransporter 2 (SGLT2) inhibitors for type 2 diabetes mellitus.

THE AIM OF THIS STUDY

was to determine the protective and repairing effect of EMPA in a model of vascular endothelial and SMC damage with 25-hydroxycholesterol (25-OHC).

METHODS

Human umbilical vascular endothelial cells (HUVECs) and SMCs were treated with compounds which induce DNA single-strand breaks (SSBs) and subjected to comet assay. Oxidative DNA damage was detected using endonuclease III (Nth) or human 8 oxoguanine DNA glycosylase (hOOG1). Reactive oxygen species (ROS) formation was determined by the fluorescence of a 6-carboxy-2',7'-dichlorodihydrofluoresce probe in diacetate (H2DCFDA).

RESULTS

25-OHC-stimulated SMCs showed greater resistance to ROS generation and DNA damage compared to HUVECs. In both experimental models, EMPA treatment was associated with lower ROS production and DNA damage, including oxidative damage to purines and pyrimidines. This effect was not dose-dependent. EMPA was found to counteract this DNA damage by inhibiting ROS production.

CONCLUSIONS

It appears that the EMPA induced indirect repair of DNA by inhibiting ROS production.

Inhibition of P21-activated Kinase 1 Promotes Vascular Smooth Muscle Cells Apoptosis Through Reduction of Phosphorylation of Bad

BACKGROUND

P21-activated kinase 1 (Pak1) has an effect on cell apoptosis and has recently been reported to play an important role in various cardiovascular diseases, in which vascular smooth muscle cell (VSMC) apoptosis is a key process. Thus, we hypothesized that Pak1 may be a novel target to regulate VSMC behaviors.

METHODS AND RESULTS

In the present study, we found that the expression of Pak1 was dramatically upregulated in vascular smooth muscle cells (VSMCs) on H2O2 administration and was dependent on stimulation time. Through a loss-of-function approach, Pak1 knockdown increased apoptosis of VSMCs, as tested by TUNEL (TdT-mediated dUTP Nick-End Labeling) immunofluorescence staining, whereas it inhibited the proliferation of VSMCs examined by EdU staining. Moreover, we also noticed that Pak1 silencing promoted the mRNA and protein levels of pro-apoptosis genes but decreased anti-apoptosis marker expression. Importantly, we showed that Pak1 knockdown reduced the phosphorylation of Bad. Moreover, increased Pak1 expression was also noticed in carotid arteries on the wire jury.

CONCLUSIONS

Our study identified that Pak1 acted as a novel regulator of apoptosis of VSMCs partially through phosphorylation of Bad.

Insights into elastic fiber fragmentation: Mechanisms and treatment of aortic aneurysm in Marfan syndrome

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by mutations in fibrillin 1 (FBN1) gene. These mutations result in defects in the skeletal, ocular, and cardiovascular systems. Aortic aneurysm is the leading cause of premature mortality in untreated MFS patients. Elastic fiber fragmentation in the aortic vessel wall is a hallmark of MFS-associated aortic aneurysms. FBN1 mutations result in FBN1 fragments that also contribute to elastic fiber fragmentation. Although recent research has advanced our understanding of MFS, the contribution of elastic fiber fragmentation to the pathogenesis of aneurysm formation remains poorly understood. This review provides a comprehensive overview of the molecular mechanisms of elastic fiber fragmentation and its role in the pathogenesis of aortic aneurysm progression. Increased comprehension of elastic fragmentation has significant clinical implications for developing targeted interventions to block aneurysm progression, which would benefit not only individuals with Marfan syndrome but also other patients with aneurysms. Moreover, this review highlights an overlooked connection between inhibiting aneurysm and the restoration of elastic fibers in the vessel wall with various aneurysm inhibitors, including drugs and chemicals. Investigating the underlying molecular mechanisms could uncover innovative therapeutic strategies to inhibit elastin fragmentation and prevent the progression of aneurysms.

MiR-122 knockdown regulates vascular smooth muscle cells phenotypic switching through enhanced FOXO3 expression

Vascular smooth muscle cells (VSMCs) phenotypic switching is identified as enhanced dedifferentiation, proliferation, and migration ability of VSMCs, in which microRNAs have been identified as important regulators of the process. The present study is aimed to explore the pathophysiological effect of miR-122 on VSMC phenotypic modulation. Here, the result showed that the decreased miR-122 expression was found in VSMCs subjected to platelet-derived growth factor-BB (PDGF-BB) treatment. Next, we investigated the response of miR-122 knockdown in VSMCs with PDGF-BB stimulation. MiR-122 silencing showed increased proliferation and migration capability, whereas attenuated the differentiation markers expression. The above results were reversed by miR-122 overexpression. Finally, we further demonstrated that FOXO3 was an important target for miR-122. Collectively, we demonstrated that miR-122 silencing promoted VSMC phenotypic modulation partially through upregulated FOXO3 expression that indicated miR-122 may be a novel therapeutic target for neointimal formation.

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.

IL-1β-mediated adaptive reprogramming of endogenous human cardiac fibroblasts to cells with immune features during fibrotic remodeling

The source and roles of fibroblasts and T-cells during maladaptive remodeling and myocardial fibrosis in the setting of pulmonary arterial hypertension (PAH) have been long debated. We demonstrate, using single-cell mass cytometry, a subpopulation of endogenous human cardiac fibroblasts expressing increased levels of CD4, a helper T-cell marker, in addition to myofibroblast markers distributed in human fibrotic RV tissue, interstitial and perivascular lesions in SUGEN/Hypoxia (SuHx) rats, and fibroblasts labeled with pdgfrα CreERt2/+ in R26R-tdTomato mice. Recombinant IL-1β increases IL-1R, CCR2 receptor expression, modifies the secretome, and differentiates cardiac fibroblasts to form CD68-positive cell clusters. IL-1β also activates stemness markers, such as NANOG and SOX2, and genes involved in dedifferentiation, lymphoid cell function and metabolic reprogramming. IL-1β induction of lineage traced primary mouse cardiac fibroblasts causes these cells to lose their fibroblast identity and acquire an immune phenotype. Our results identify IL-1β induced immune-competency in human cardiac fibroblasts and suggest that fibroblast secretome modulation may constitute a therapeutic approach to PAH and other diseases typified by inflammation and fibrotic remodeling.

Secreted protein profiling of human aortic smooth muscle cells identifies vascular disease associations

Background

Smooth muscle cells (SMCs), which make up the medial layer of arteries, are key cell types involved in cardiovascular diseases (CVD), the leading cause of mortality and morbidity worldwide. In response to microenvironment alterations, SMCs dedifferentiate from a "contractile" to a "synthetic" phenotype characterized by an increased proliferation, migration, production of extracellular matrix (ECM) components, and decreased expression of SMC-specific contractile markers. These phenotypic changes result in vascular remodeling and contribute to the pathogenesis of CVD, including coronary artery disease (CAD), stroke, hypertension, and aortic aneurysms. Here, we aim to identify the genetic variants that regulate ECM secretion in SMCs and predict the causal proteins associated with vascular disease-related loci identified in genome-wide association studies (GWAS).

Methods

Using human aortic SMCs from 123 multi-ancestry healthy heart transplant donors, we collected the serum-free media in which the cells were cultured for 24 hours and conducted Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic analysis of the conditioned media.

Results

We measured the abundance of 270 ECM and related proteins. Next, we performed protein quantitative trait locus mapping (pQTL) and identified 20 loci associated with secreted protein abundance in SMCs. We functionally annotated these loci using a colocalization approach. This approach prioritized the genetic variant rs6739323-A at the 2p22.3 locus, which is associated with lower expression of LTBP1 in SMCs and atherosclerosis-prone areas of the aorta, and increased risk for SMC calcification. We found that LTBP1 expression is abundant in SMCs, and its expression at mRNA and protein levels was reduced in unstable and advanced atherosclerotic plaque lesions.

Conclusions

Our results unravel the SMC proteome signature associated with vascular disorders, which may help identify potential therapeutic targets to accelerate the pathway to translation.

Soluble guanylyl cyclase: A novel target for the treatment of vascular cognitive impairment?

Vascular cognitive impairment (VCI) describes neurodegenerative disorders characterized by a vascular component. Pathologically, it involves decreased cerebral blood flow (CBF), white matter lesions, endothelial dysfunction, and blood-brain barrier (BBB) impairments. Molecularly, oxidative stress and inflammation are two of the major underlying mechanisms. Nitric oxide (NO) physiologically stimulates soluble guanylate cyclase (sGC) to induce cGMP production. However, under pathological conditions, NO seems to be at the basis of oxidative stress and inflammation, leading to a decrease in sGC activity and expression. The native form of sGC needs a ferrous heme group bound in order to be sensitive to NO (Fe(II)sGC). Oxidation of sGC leads to the conversion of ferrous to ferric heme (Fe(III)sGC) and even heme-loss (apo-sGC). Both Fe(III)sGC and apo-sGC are insensitive to NO, and the enzyme is therefore inactive. sGC activity can be enhanced either by targeting the NO-sensitive native sGC (Fe(II)sGC), or the inactive, oxidized sGC (Fe(III)sGC) and the heme-free apo-sGC. For this purpose, sGC stimulators acting on Fe(II)sGC and sGC activators acting on Fe(III)sGC/apo-sGC have been developed. These sGC agonists have shown their efficacy in cardiovascular diseases by restoring the physiological and protective functions of the NO-sGC-cGMP pathway, including the reduction of oxidative stress and inflammation, and improvement of vascular functioning. Yet, only very little research has been performed within the cerebrovascular system and VCI pathology when focusing on sGC modulation and its potential protective mechanisms on vascular and neural function. Therefore, within this review, the potential of sGC as a target for treating VCI is highlighted.

Early clinical outcomes and molecular smooth muscle cell phenotyping using a prophylactic aortic arch replacement strategy in Loeys-Dietz syndrome

OBJECTIVES

Patients with Loeys-Dietz syndrome demonstrate a heightened risk of distal thoracic aortic events after valve-sparing aortic root replacement. This study assesses the clinical risks and hemodynamic consequences of a prophylactic aortic arch replacement strategy in Loeys-Dietz syndrome and characterizes smooth muscle cell phenotype in Loeys-Dietz syndrome aneurysmal and normal-sized downstream aorta.

METHODS

Patients with genetically confirmed Loeys-Dietz syndrome (n = 8) underwent prophylactic aortic arch replacement during valve-sparing aortic root replacement. Four-dimensional flow magnetic resonance imaging studies were performed in 4 patients with Loeys-Dietz syndrome (valve-sparing aortic root replacement + arch) and compared with patients with contemporary Marfan syndrome (valve-sparing aortic root replacement only, n = 5) and control patients (without aortopathy, n = 5). Aortic tissues from 4 patients with Loeys-Dietz syndrome and 2 organ donors were processed for anatomically segmented single-cell RNA sequencing and histologic assessment.

RESULTS

Patients with Loeys-Dietz syndrome valve-sparing aortic root replacement + arch had no deaths, major morbidity, or aortic events in a median of 2 years follow-up. Four-dimensional magnetic resonance imaging demonstrated altered flow parameters in patients with postoperative aortopathy relative to controls, but no clear deleterious changes due to arch replacement. Integrated analysis of aortic single-cell RNA sequencing data (>49,000 cells) identified a continuum of abnormal smooth muscle cell phenotypic modulation in Loeys-Dietz syndrome defined by reduced contractility and enriched extracellular matrix synthesis, adhesion receptors, and transforming growth factor-beta signaling. These modulated smooth muscle cells populated the Loeys-Dietz syndrome tunica media with gradually reduced density from the overtly aneurysmal root to the nondilated arch.

CONCLUSIONS

Patients with Loeys-Dietz syndrome demonstrated excellent surgical outcomes without overt downstream flow or shear stress disturbances after concomitant valve-sparing aortic root replacement + arch operations. Abnormal smooth muscle cell-mediated aortic remodeling occurs within the normal diameter, clinically at-risk Loeys-Dietz syndrome arch segment. These initial clinical and pathophysiologic findings support concomitant arch replacement in Loeys-Dietz syndrome.

Acetylation in pathogenesis: Revealing emerging mechanisms and therapeutic prospects

Protein acetylation modifications play a central and pivotal role in a myriad of biological processes, spanning cellular metabolism, proliferation, differentiation, apoptosis, and beyond, by effectively reshaping protein structure and function. The metabolic state of cells is intricately connected to epigenetic modifications, which in turn influence chromatin status and gene expression patterns. Notably, pathological alterations in protein acetylation modifications are frequently observed in diseases such as metabolic syndrome, cardiovascular disorders, and cancer. Such abnormalities can result in altered protein properties and loss of function, which are closely associated with developing and progressing related diseases. In recent years, the advancement of precision medicine has highlighted the potential value of protein acetylation in disease diagnosis, treatment, and prevention. This review includes provocative and thought-provoking papers outlining recent breakthroughs in acetylation modifications as they relate to cardiovascular disease, mitochondrial metabolic regulation, liver health, neurological health, obesity, diabetes, and cancer. Additionally, it covers the molecular mechanisms and research challenges in understanding the role of acetylation in disease regulation. By summarizing novel targets and prognostic markers for the treatment of related diseases, we aim to contribute to the field. Furthermore, we discuss current hot topics in acetylation research related to health regulation, including N4-acetylcytidine and liquid-liquid phase separation. The primary objective of this review is to provide insights into the functional diversity and underlying mechanisms by which acetylation regulates proteins in disease contexts.

Exploring the role of osteoglycin in type 2 diabetes: implications for insulin resistance and vascular pathophysiology

Osteoglycin, a fundamental proteoglycan within the vascular extracellular matrix, is expressed in vascular smooth muscle cells (VSMCs). Type 2 diabetes (T2D) is associated with cardiovascular disease (CVD) but the role of osteoglycin in the development of CVD is controversial to date. Therefore, our aims are to determine and compare the level of osteoglycin in T2D patients with/without CVD versus control subjects both at serum and vascular tissue and to analyze in vitro role of osteoglycin in VSMCs under calcified conditions. For this, serum osteoglycin levels were determined by enzyme-linked immunosorbent assay (ELISA) in 117 controls and 129 patients with T2D (46 with CVD and 83 without CVD), revealing a significant increase in patients with T2D compared with controls. Osteoglycin level was not an estimator of CVD but correlated with markers of insulin resistance (triglycerides and triglycerides/high-density lipoprotein cholesterol index) in patients with T2D. At the vascular level, osteoglycin expression was assessed by RT-qPCR and immunohistochemistry, and no significant differences were observed between calcified arteries from patients with T2D and noncalcified arteries from controls. In vitro experiments using VSMCs (mock and overexpressing osteoglycin) under calcifying conditions were performed to analyze the osteoglycin function. The overexpression of osteoglycin in VMSCs under calcifying conditions revealed an increase of cell proliferation without effect on apoptosis and an upregulation of the expression of autotaxin (ATX) involved in inflammatory processes. In conclusion, osteoglycin could play a role in glycemic homeostasis, being a potential biomarker of insulin resistance in patients with T2D. Furthermore, osteoglycin could indirectly participate in the development of atherosclerosis through its regulatory effect on ATX and by proliferating VSMCs.NEW & NOTEWORTHY This study uncovers an increase of serum osteoglycin levels in patients with type 2 diabetes, which does not appear to be associated with the development of atherosclerosis, but rather with insulin resistance in this population. Overexpression of osteoglycin increased proliferation and upregulated the expression of autotaxin in vascular smooth muscle cells within calcified environments. Osteoglycin could be a biomarker of insulin resistance for type 2 diabetes and could be indirectly involved in the development of atherosclerosis.