A novel mechanism of ferroptosis inhibition-enhanced atherosclerotic plaque stability: YAP1 suppresses vascular smooth muscle cell ferroptosis through GLS1.

Atherosclerosis is a leading cause of cardiovascular diseases (CVDs), often resulting in major adverse cardiovascular events (MACEs), such as myocardial infarction and stroke due to the rupture or erosion of vulnerable plaques. Ferroptosis, an iron-dependent form of cell death, has been implicated in the development of atherosclerosis. Despite its involvement in CVDs, the specific role of ferroptosis in atherosclerotic plaque stability remains unclear. In this study, we confirmed the presence of ferroptosis in unstable atherosclerotic plaques and demonstrated that the ferroptosis inhibitor ferrostatin-1 (Fer-1) stabilizes atherosclerotic plaques in apolipoprotein E knockout (Apoe-/-) mice. Using bioinformatic analysis combining RNA sequencing (RNA-seq) with single-cell RNA sequencing (scRNA-seq), we identified Yes-associated protein 1 (YAP1) as a potential key regulator of ferroptosis in vascular smooth muscle cells (VSMCs) of unstable plaques. In vitro, we found that YAP1 protects against oxidized low-density lipoprotein (oxLDL)-induced ferroptosis in VSMCs. Mechanistically, YAP1 exerts its anti-ferroptosis effects by regulating the expression of glutaminase 1 (GLS1) to promote the synthesis of glutamate (Glu) and glutathione (GSH). These findings establish a novel mechanism where the inhibition of ferroptosis promotes the stabilization of atherosclerotic plaques through the YAP1/GLS1 axis, attenuating VSMC ferroptosis. Thus, targeting the YAP1/GLS1 axis to suppress VSMC ferroptosis may represent a novel strategy for preventing and treating unstable atherosclerotic plaques.

Adipokine-Cytokine Profile in Patients with Unstable Atherosclerotic Plaques and Abdominal Obesity.

The goal of the research was to study the levels of adipokines and their associations with unstable atherosclerotic plaques in patients with coronary atherosclerosis and abdominal obesity (AO). METHODS: The study included 145 men aged 38-79 with atherosclerosis of the coronary arteries (CA) and stable angina pectoris II-III FC who were hospitalized for coronary bypass surgery (2011-2022). The final analysis included 116 patients. Notably, 70 men had stable plaques in the CA (of which 44.3% had AO), and 46 men had unstable plaques in the CA (of which 43.5% had AO). Adipocytokine levels were determined using multiplex analysis (Human Metabolic Hormone V3 panel). RESULTS: In the subgroup of patients with unstable plaques, patients with AO had a GLP-1 level that was 1.5 times higher and a lipocalin-2 level that was 2.1 times lower, respectively. GLP-1 is direct, and lipocalin-2 is inversely associated with AO in patients with unstable plaques. Among patients with AO, the level of lipocalin-2 in patients with unstable plaques was 2.2 times lower than in patients with stable plaques in the CA. The level of lipocalin-2 was inversely associated with the presence of unstable atherosclerotic plaques in the CA. CONCLUSION: GLP-1 is directly associated with AO in patients with unstable atherosclerotic plaques. Lipocalin-2 is inversely associated with unstable atherosclerotic plaques in patients with AO.

[Pathological changes in the nervous structures of the aortic wall tissue adjacent to an unstable atherosclerotic plaque]. / Patologicheskie izmeneniya nervnykh struktur v tkanyakh stenki aorty, prilezhashchikh k nestabil'noi ateroskleroticheskoi blyashke.

OBJECTIVE: To study of nerve structures in the aortic wall in atherosclerosis using a complex of immunohistochemical markers. MATERIAL AND METHODS: The objects of the study were excised fragments of the wall of the thoracic and abdominal aorta along with visually determined unstable atherosclerotic plaques. To study nerve structures on paraffin sections, immunohistochemical reactions were performed for the PGP 9.5 protein, tyrosine hydroxylase, and synaptophysin. RESULTS: It has been established that pronounced pathological changes are observed in the nervous structures of the aortic wall near unstable atherosclerotic plaques. Reactive, dystrophic, and severe degenerative changes in neurocytes, nerve fibers, and glial cells are described in the elements of the nervous apparatus of the adventitia (microganglia, nerve trunks, and nerve plexuses). It was found that only sympathetic neurons and their postganglionic fibers remain in the intramural ganglia, while the structures of the parasympathetic nervous apparatus undergo degeneration. Destruction of perivascular nerve plexuses and vasa vasorum in the adventitia, as well as degeneration of varicose axons of the main terminal synaptic plexus at the border of adventitia and superficial smooth muscle layer of the media were demonstrated. CONCLUSION: It is assumed that the presence of inflammatory infiltrates in the adventitia and intima, denervation and death of vasa vasorum can serve as factors determining the development of the atherosclerotic process.

Brussels Chicory Stabilizes Unstable Atherosclerotic Plaques and Reshapes the Gut Microbiota in Apoe-/- Mice.

BACKGROUND: Adherence to a Mediterranean dietary pattern can protect against atherosclerosis in part by reducing intestinal permeability and gut microbial LPS production. Brussels chicory, a typical Mediterranean vegetable, has been shown to inhibit the formation of early-stage atherosclerosis in mice. OBJECTIVES: We evaluated whether Brussels chicory affects advanced atherosclerosis progression, intestinal permeability, and gut microbial LPS production. METHODS: Thirty-week-old male apoE-deficient mice with unstable atherosclerotic plaques in the brachiocephalic artery were fed the AIN-93G diet alone (control) or supplemented with 0.5% freeze-dried Brussels chicory for 20 wk. Plaque volume and features of plaque stability, plaque macrophage polarization, fecal and serum LPS concentrations, serum lipid profiles and inflammation-related cytokines, and gut microbial profiles were measured. RESULTS: Compared with the control treatment, Brussels chicory consumption did not significantly change plaque volume and serum lipid profiles. However, it increased plaque stability (P < 0.05), as evidenced by reduced necrotic core size (42.3%), and increased fibrous cap thickness (55.0%) and collagen content (68.4%). Moreover, Brussels chicory consumption reduced intestinal permeability (56.3%), fecal and serum LPS concentrations (52.2% and 39.4%), serum IL1ß and TNFα (52.0% and 33.8%), promoted plaque macrophage polarization towards the M2-like phenotype, and altered gut microbial composition, the latter indicated by increased relative abundance of certain members of the Ruminococcaceae family, such as Ruminiclostridium_9, Ruminiclostridium_5, and Intestinimonas (P < 0.05). Spearman correlation analyses further showed that these bacterial genera were significantly correlated with intestinal permeability, fecal and serum LPS, serum proinflammatory cytokines, and several features of plaque stability. CONCLUSIONS: Brussels chicory might help stabilize atherosclerotic plaques in mice by reducing intestinal permeability and gut microbial LPS production. This study provides a promising approach to slow the progression of atherosclerosis.

[The role of neovascularization in the formation of an unstable human atherosclerotic plaque]. / Rol' neovaskulyarizatsii v formirovanii nestabil'noi ateroskleroticheskoi blyashki u cheloveka.

MATERIAL AND METHODS: The study material was 20 autopsy samples obtained from males aged 65 to 72 years who died from acute atherosclerotic cardiovascular insufficiency. Aortic segments (from the arch, thoracic and abdominal regions), coronary arteries and the arteries of the base of the brain (a. basilaris) were investigated; these totaled 45 tissue segments. Neovessels and cellular responses in the arterial wall were examined by hematoxylin and eosin staining. VEGF was immunohistochemically detected using a highly sensitive two-stage streptavidin-biotin method. RESULTS: In unstable atherosclerotic lesions, there were active neovascularization processes in both the fibrous cap and the underlying parts of the adventitia. These changes are usually combined with a pronounced cellular inflammatory response that can contribute to their development. Endothelial growth factor may be one of the causes of neovascularization in unstable atherosclerotic lesions. CONCLUSION: A comparative immunomorphological study in the human aorta, coronary arteries, and a. basilaris revealed active neovascularization processes in the cap and the underlying parts of the adventitia in unstable atherosclerotic lesions. The cause of this neovascularization is probably endothelial growth factor and cellular inflammatory responses.

Immune complexes containing malondialdehyde (MDA) LDL induce apoptosis in human macrophages.

Immune complexes (IC) containing predominantly malondialdehyde-LDL and the corresponding autoantibodies (MDA-LDL IC) predict acute cardiovascular events, while IC rich in oxidized LDL (oxLDL IC) predict cardiovascular disease progression. Our objective was to determine mechanisms that could explain these prognostic differences. We compared the effects of the interaction of oxLDL, MDA-LDL and the corresponding IC with human macrophages focusing on apoptosis, metalloproteinases, and proinflammatory cytokines. MDA-LDL IC induced higher degrees of apoptosis, higher levels of caspase-3 expression, and increased expression and release of MMP-1 and TNF compared to MDA-LDL, oxLDL, and oxLDL IC. The pro-apoptotic effects of MDA-LDL IC were inhibited by blocking TNFR 1 or FcγRI. Blocking FcγRI abrogated the induction and expression of MMPs and proinflammatory cytokines by MDA-LDL IC. In conclusion, the interaction of MDA-LDL IC with FcγRI triggers macrophage apoptosis and increased expression and release of TNF and MMP-1, which can lead to the rupture of unstable plaques.

The underlying molecular mechanisms and biomarkers of plaque vulnerability based on bioinformatics analysis.

AIM: The study aimed to identify the underlying differentially expressed genes (DEGs) and mechanism of unstable atherosclerotic plaque using bioinformatics methods. METHODS: GSE120521, which includes four unstable samples and four stable atherosclerotic samples, was downloaded from the GEO database. DEGs were identified using LIMMA. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs were performed using the Database for metascape Visualization online tool. Based on the STRING database, protein-protein interactions (PPIs) network among DEGs were constructed. Regulatory networks were visualized using Cytoscape. We use the xCell to analyze the different immune cell subtypes. RESULTS: A total of 1626 DEGs (1034 up-regulated and 592 down-regulated DEGs) were identified between unstable and stable samples. I pulled 62 transcription factors (34 up-regulated TFs and 28 down-regulated TFs) from the Trust database. The up-regulated TFs were mainly enrichment in positive regulation of myeloid leukocyte differentiation, and the down-regulated TFs were mainly enrichment in connective tissue development. In the PPI network, RB1, CEBPA, PPARG, BATF was the most significantly up-regulated gene in ruptured atherosclerotic samples. The immune cell composition enriched in CD cells and macrophages in the unstable carotid plaque. CONCLUSIONS: Upregulated RB1, CEBPA, PPARG, BATF and down-regulated SRF, MYOCD, HEY2, GATA6 might perform critical promotional roles in atherosclerotic plaque rupture, furthermore, number and polarization of macrophages may play an important role in vulnerable plaques.

Dual-modality Imaging of Angiogenesis in Unstable Atherosclerotic Plaques with VEGFR2-Targeted Upconversion Nanoprobes in vivo.

AIM: Angiogenesis plays a major role in atherosclerotic plaque development and instability. Our study aims to develop a novel optical and magnetic resonance (MR) dual-modality molecular imaging probe to early detect unstable plaques in vivo by targeting biomarkers of angiogenesis in murine models of atherosclerosis (AS). METHODS: Immunofluorescence and western blot were used to detect the expression of Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) in activated Human Umbilical Vein Endothelial Cells (HUVECs). After synthesis and identification of novel short peptide VRBP1-targeted VEGFR2, HUVECs were co-cultured with FITC-VRBP1 to test specific affinity of VRBP1. Then VRBP1-UCNPstargeting VEGFR2 were constructed by conjugating VRBP1 to the surface of NaGdF4:Yb,Er@NaGdF4 nanoparticles. The characterization of the nanoparticles was performed by transmission electron microscopy (TEM), distribution of size, hydrodynamic size, zeta potential, absorption spectra, emission spectra, imaging intensity of different concentrations, binding affinity and cytotoxicity of nanoprobes in vitro. The upconversion luminescence (UCL) and MR imaging were performed to identify unstable atherosclerotic plaque in ApoE-/- mice in vivo and ex vivo. Morphological staining was used to verify AS model and angiogenesis, and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) was used to confirm accumulation of the nanoparticles after imaging. RESULTS: After induced by hypoxia and ox-LDL, the expression of VEGFR2 in activated HUVECs was enhanced. FITC-VRBP1 can specifically bind to the HUVECs. Characterization of the nanoparticles showed that particles size is uniform with a stable structure, specific optical and MR signal, good binding affinity to VEGFR2 and low cytotoxicity. In vivo and ex vivo UCL imaging and quantitative analysis revealed that distinctive optical signal was observed in the regions of left carotid common arteries (LCCAs) of AS group after injection of VRBP1-UCNPs. Higher signal intensity on T1-weighted MR imaging appeared in the LCCA wall of AS group after injection. The results of morphological staining demonstrated angiogenesis in the atherosclerotic plaques, Gd ions in LCCAs, aortic arch and renal arteries bifurcations detected by ICP-AES confirmed accumulation of the nanoparticles in plaque. CONCLUSIONS: We successfully design and synthesize a novel UCNPs using peptide VRBP1 targeting to VEGFR2. In vivo imaging demonstrates that VRBP1-UCNPs can be used to perform optical/MR dual-modality imaging targeting angiogenesis in plaques, which is a promising technique to early detect unstable atherosclerosis.

Adipokine Levels in Men with Coronary Atherosclerosis on the Background of Abdominal Obesity.

Background. Obesity is associated with dyslipidemia, and excess body fat is associated with unfavorable levels of adipokines and markers of inflammation. The goal of research. To study the level of adipokines and markers of inflammation, their associations with unstable atherosclerotic plaques in men with coronary atherosclerosis on the background of abdominal obesity. Materials and methods. The study involved 82 men aged 40-77 years with coronary atherosclerosis after endarterectomy from the coronary arteries. We divided all men into two groups: 37 men (45.1%) with unstable atherosclerotic plaques, and 45 men (54.9%) who had stable plaques. Obesity was established at a BMI of ≥30 kg/m2. The levels of adipokines and markers of inflammation in the blood were determined by multiplex analysis. Results. In patients with obesity and unstable plaques, the levels of C-peptide, TNFa and IL-6 were 1.8, 1.6, and 2.8 times higher, respectively, than in patients with obesity and stable plaques. The chance of having an unstable plaque increases with an increase in TNFa by 49% in obese patients and decreases with an increase in insulin by 3% in non-obese patients. Conclusions. In men with coronary atherosclerosis and obesity, unstable atherosclerotic plaques in the coronary arteries are directly associated with the level of TNF-α.

Bioinformatics Gene Analysis of Potential Biomarkers and Therapeutic Targets for Unstable Atherosclerotic Plaque-Related Stroke.

Atherosclerotic plaque instability is a major cause of ischemic stroke. Researchers must develop novel strategies for the detection and treatment of unstable atherosclerotic plaque (UAP)-related stroke. We aimed to identify potential biomarkers and therapeutic targets of UAP-related stroke. Differentially expressed genes (DEGs) of UAP, ischemic stroke and smoking were identified by microarray analyses from the Gene Expression Omnibus. Gene Ontology (GO) and pathway functional enrichment analyses of DEGs were performed to analyze plaque destabilization and ischemic stroke physiopathology. An integrative analysis of UAP, ischemic stroke and smoking DEGs and functional annotations was performed to identify the underlying physiopathology and hub genes in UAP-related stroke and the relationship with smoking. Online search databases were applied to confirm hub gene biofunctions and their relationships with atherosclerosis and cerebrovascular diseases. Following integrative analysis, 18 co-DEGs of UAP and ischemic stroke, including 17 upregulated and one downregulated, were identified. Inflammation, immunity, extracellular matrix degradation, blood coagulation, apoptosis and nerve degeneration were the primary physiopathological processes in UAP-related stroke. Hub genes included MMP9, ITGAM, CCR1, NCF2 and CD163, among which MMP9 and ITGAM were top 10 genes for both UAP and stroke. Smoking may upregulate MMP9, NCF2, C5AR1 and ANPEP to accelerate plaque destabilization and UAP-related stroke. MMP9, ITGAM, CCR1, NCF2, CD163, hsa-miR-3123 and hsa-miR-144-3p are potential diagnostic and prognostic biomarkers of UAP-related stroke. MMP9 and ITGAM are potential therapeutic targets of UAP-related stroke, which will contribute to the development of novel management strategies.

The Influence of Calcification Factors and Endothelial-Dysfunction Factors on the Development of Unstable Atherosclerotic Plaques.

BACKGROUND: This study aimed to evaluate changes in markers of calcification and of endothelial dysfunction during the development of calcification and instability of atherosclerotic plaques and to identify associations of calcification factors with the formation of unstable plaques. METHODS: We analyzed 44 male patients with coronary atherosclerosis who underwent endarterectomy in coronary arteries during coronary bypass surgery. The endarterectomy material (intima/media) was examined using histological and biochemical methods, and the stability and calcification degree of atherosclerotic plaques were assessed. In homogenates of the tissue samples and in blood, concentrations of osteoprotegerin, osteocalcin, osteopontin, osteonectin, monocyte-chemoattractant protein type 1 (MCP-1), soluble vascular cell adhesion molecule 1 (sVCAM-1), and E-selectin were determined by enzyme immunoassays. RESULTS: Unstable atherosclerotic plaques proved to be calcified more frequently (80.4% of plaques) than stable ones (45.0%). Osteonectin, E-selectin, and sVCAM-1 levels were lower in unstable plaques and plaques with large calcification deposits. Osteocalcin content increased with the increasing size of the calcification deposits in plaque. Blood osteocalcin concentration directly correlated with osteocalcin concentration in atherosclerotic plaques and was higher in the blood of patients with calcified plaques in coronary arteries. CONCLUSIONS: The results provide the basis for further research on the suitability of osteocalcin as a potential biomarker of an unstable calcified atherosclerotic plaque in a coronary artery.