Human Coronary Atherosclerosis Research Articles

Early coronary artery atherosclerosis in humans is associated with attenuated coronary retention of klotho

Abstract Background Vascular aging is a key feature of cardiovascular disease. α-klotho (klotho) is a protein inversely associated with aging and may contribute to vascular repair. Lower levels of systemic klotho have been identified in humans with features of early and advanced coronary atherosclerosis. It remains unknown if circulating klotho is present within human coronary circulation and whether cardiovascular klotho retention correlates with atherosclerosis. Purpose The current study aimed to assess the presence of klotho within coronary circulation compared to systemic circulation and hypothesized that net coronary klotho retention is attenuated in patients with early age-related features of coronary artery disease (CAD). Methods A total of 42 patients that underwent clinically indicated coronary angiogram for chest pain that had no obstructive CAD underwent intravascular ultrasound (IVUS) assessment were retrospectively examined. Virtual histology assessed coronary plaque characteristics. Blood samples simultaneously collected from the proximal aorta and coronary sinus were used for klotho detection using enzyme-linked immunosorbent assay. The net gradient of klotho across cardiovascular circulation was calculated by multiplying the arteriovenous klotho gradient by basal coronary blood flow. A net positive gradient indicated less cardiovascular klotho retention; a net negative gradient indicated greater cardiovascular klotho retention. Results Overall, participants were age 54±10 years old and 76% were female. There were overall higher levels of klotho within the coronary sinus (median 0.49 ng/mL [0.15; 1.69]) compared to systemic circulation (median 0.30 ng/mL [0.16; 1.14]). Participant groups were determined by those with positive (n = 20) or negative (n = 22) cardiovascular retention of klotho. Both groups were similar in age (56 ±2 vs. 51 ±2 years old, p = 0.080), gender (72% vs. 80% female, p = 0.580), and had similar occurrences of traditional cardiovascular comorbidities. Those with less cardiovascular klotho retention in the coronary vascular bed had significantly greater degree of non-obstructive coronary artery plaque (Gensini score 3.5 vs. 0, p < 0.001) and had higher percent plaque burden (46% [35; 53] vs. 34% [28; 46], p = 0.044) than those with greater cardiovascular klotho retention. Conclusions Patients with early coronary atherosclerosis may be characterized by attenuated retention of klotho within coronary circulation. Moreover, humans appear to have higher circulating klotho in coronary circulation than in systemic circulation. The current study may support a role for mechanism or potential therapeutic target for klotho in coronary atherosclerosis in humans.

Vitamin K2 and the Vitamin-K-Cycle-Enzyme VKORC1L1 improve endothelial regeneration by inhibiting endothelial-mesenchymal transition, inflammatory cell activation and ferroptosis

Abstract Introduction Vascular inflammation is a crucial contributor to atherosclerosis, in which oxidative stress, endoplasmic reticulum (ER) stress and transition of endothelial to mesenchymal cells (EndMT) are of critical importance. Vitamin-K-antagonists (VKA) promote vascular dysfunction, while dietary vitamin K intake was proposed to reduce incidence of coronary artery disease, but the mechanisms remain unresolved. Key enzyme for regeneration of vitamin K is the Vitamin K epoxide reductase complex subunit 1 (VKORC1), which also represents the pharmacological target of VKA. VKOR-like1 (VKORC1L1) is an isoenzyme of VKORC1, which resides at the ER-membrane, exerts antioxidative properties and is involved in vitamin K maintenance. Aim of this study was to investigate the role of Vitamin K2 and the VKOR-enzymes in endothelial cell inflammation. Methods and Results In human coronary artery endothelial cells (HCAEC), Vitamin K2 improves endothelial regeneration by increasing proliferation and cell viability and by reducing both apoptosis and ferroptosis (relative viability: RSL3 0.11 ± 0.01 vs 0.32 ± 0.05 RSL3+K2-1µM vs. 0.44 ± 0.11 RSL3+K2-10µM, p<0.001). Moreover, Vitamin K2-supplementation inhibits EndMT by reducing expression of mesenchymal markers (Calponin, SM22; Fig.1). In silico analyses of the proteome of human coronary atherosclerosis revealed increased expression of VKORC1L1, but not of VKORC1. In vitro induction of oxidative stress and ER-Stress promoted time- and dose-dependent enhanced expression of VKORC1L1, without altering VKORC1 expression (H2O2: 2.3-fold vs. 0.8-fold after 40 minutes, p=0.04; tunicamycin: 1 μg/ml: 1.43-fold vs. 0.8-fold, p<0.01). Likewise, siRNA-mediated VKORC1L1 knockdown induces an inflammatory gene signature with upregulation of NFkB-signalling and endoplasmic reticulum stress (NF-κB: 1.95-fold ± 0.13, GRP78: 1.32-fold ± 0.04 vs. control, p<0.01). Furthermore, VKORC1L1 downregulation increased formation of reactive oxygen species (ROS) and reduced proliferation (EdU signal: 0.56 ± 0.02 vs. control, p < 0.01). In contrast, VKORC1-knockdown does not impair endothelial regeneration and function (Fig.2). Vitamin K2 reduces vascular inflammation and endoplasmic reticulum stress in the case of VKORC1-, but not VKORC1L1-knockdown. In addition, inducing EndMT resulted in a reduction of VKORC1L1, but not of VKORC1, while VKORC1L1-knockdown aggravates EndMT. Conclusion VKORC1 and its isoenzyme VKORC1L1 exhibit divergent effects on endothelial cell inflammation. Further studies are warranted to shed light on the regulation of the enzymes to improve our understanding regarding vascular side effects of VKA treatment and beneficial effects of vitamin K supplementation.

Correlation of circulatory VEGF and miRNA 126 in angiographically proven coronary artery disease and its clinical importance

Background: Atherosclerotic ischemic coronary artery disease (CAD) is a major cause of morbidity and mortality in both developed and developing countries, indicating the need for the discovery of deeper molecular insights of CAD mechanisms, biomarkers, and innovative therapeutic targets. Vascular endothelial growth factor (VEGF) may have some role, in the progression of human coronary atherosclerosis. Circulating microRNAs (miR) have a potential as a diagnostic as well as a prognostic biomarker of cardiovascular disease and dysfunctions. Aims and Objectives: The aim of the study was to correlate the levels of miRNA-126 and VEGF in the serum of CAD patients. Materials and Methods: The study was conducted on 100 cases of freshly diagnosed CAD patients (angiographically proven) and 80 normal healthy patients. Various serum biomarkers were estimated. The level of serum VEGF and Mi-RNA was correlated for CAD patients. Results: Highly significantly difference was found in levels of hemoglobin A1C, low density lipoprotein, total cholesterol, and total homocysteine while high-density lipoproteins and triglycerides were less significantly different for controls and cases. VEGF levels of CAD cases were found to be very significantly higher as compared to controls. The miRNA-126 expression was found to be lower in the CAD subjects compared to non-CAD subjects. Conclusion: The study was suggested the role of VEGF in atherogenesis and plaque instability. No significant correlation was found among between miR-126 levels and VEGF levels among CAD cases. The study is limited by a smaller sample size and was single-centered; therefore, multicentric study with a larger patient cohort needs to be done and to validate our findings.

Shared and distinct pathways and networks genetically linked to coronary artery disease between human and mouse

Mouse models have been used extensively to study human coronary artery disease (CAD) or atherosclerosis and to test therapeutic targets. However, whether mouse and human share similar genetic factors and pathogenic mechanisms of atherosclerosis has not been thoroughly investigated in a data-driven manner. We conducted a cross-species comparison study to better understand atherosclerosis pathogenesis between species by leveraging multiomics data. Specifically, we compared genetically driven and thus CAD-causal gene networks and pathways, by using human GWAS of CAD from the CARDIoGRAMplusC4D consortium and mouse GWAS of atherosclerosis from the Hybrid Mouse Diversity Panel (HMDP) followed by integration with functional multiomics human (STARNET and GTEx) and mouse (HMDP) databases. We found that mouse and human shared >75% of CAD causal pathways. Based on network topology, we then predicted key regulatory genes for both the shared pathways and species-specific pathways, which were further validated through the use of single cell data and the latest CAD GWAS. In sum, our results should serve as a much-needed guidance for which human CAD-causal pathways can or cannot be further evaluated for novel CAD therapies using mouse models.

Shared and distinct pathways and networks genetically linked to coronary artery disease between human and mouse.

Mouse models have been used extensively to study human coronary artery disease (CAD) or atherosclerosis and to test therapeutic targets. However, whether mouse and human share similar genetic factors and pathogenic mechanisms of atherosclerosis has not been thoroughly investigated in a data-driven manner. We conducted a cross-species comparison study to better understand atherosclerosis pathogenesis between species by leveraging multiomics data. Specifically, we compared genetically driven and thus CAD-causal gene networks and pathways, by using human GWAS of CAD from the CARDIoGRAMplusC4D consortium and mouse GWAS of atherosclerosis from the Hybrid Mouse Diversity Panel (HMDP) followed by integration with functional multiomics human (STARNET and GTEx) and mouse (HMDP) databases. We found that mouse and human shared >75% of CAD causal pathways. Based on network topology, we then predicted key regulatory genes for both the shared pathways and species-specific pathways, which were further validated through the use of single cell data and the latest CAD GWAS. In sum, our results should serve as a much-needed guidance for which human CAD-causal pathways can or cannot be further evaluated for novel CAD therapies using mouse models.

The vitamin-k-cycle-enzyme VKORC1L1, but not its isoenzyme VKORC1, reduces inflammation in coronary endothelial cells

Abstract Introduction Vascular inflammation is a crucial contributor to atherosclerosis, in which oxidative stress, endoplasmic reticulum (ER) stress and transition of endothelial to mesenchymal cells (EndMT) are of critical importance. Vitamin-K-antagonists (VKA) promote vascular dysfunction, while vitamin K intake was proposed to reduce incidence of coronary artery disease. Key enzyme for regeneration of vitamin K is the Vitamin K epoxide reductase complex subunit 1 (VKORC1), which also represents the pharmacological target of VKA. VKOR-like1 (VKORC1L1) is an isoenzyme of VKORC1, which resides at the ER-membrane, exerts antioxidative properties and is involved in vitamin K maintenance. Aim of this study was to investigate the role of VKORC1 and VKORC1L1 in inflammation of human coronary artery endothelial cells (HCAEC). Methods and Results In silico analyses of the proteome of human coronary atherosclerosis revealed increased expression of VKORC1L1, but not of VKORC1. In vitro induction of oxidative stress (H2O2) and ER-Stress (tunicamycin) in HCAEC promoted time- and dose-dependent enhanced expression of VKORC1L1, without altering VKORC1 expression (H2O2: 2.3-fold vs. 0.8-fold after 40 minutes, p=0.04; tunicamycin: 1 μg/ml: 1.43-fold vs. 0.8-fold, p<0.01). Moreover, inducing EndMT by treatment with a differentiation medium (containing TGF-ß2, IL-1ß) resulted in a reduction of VKORC1L1, but not of VKORC1 (Fig.1). To analyze the relevance of the VKOR-enzymes on endothelial cell function, VKORC1 and VKORC1L1 were downregulated by siRNA. VKORC1L1 downregulation increased formation of reactive oxygen species (ROS) (DCFDA signal: 0.98-fold vs. 1.31-fold, p = 0.03) and reduced proliferation (EdU signal: 0.56 ± 0.02 vs. control, p < 0.01), whereas viability of HCAEC remained unchanged. ELISA and qPCR experiments revealed enhanced expression of a variety of markers of vascular inflammation after VKORC1L1 (e.g., IL-6: 3.42-fold ± 0.53, NF-κB: 1.95-fold ± 0.13, VCAM-1: 1.59-fold ± 0.12, vs. control). Additionally, expression of ER-stress markers was increased (e.g., GRP78; 1.32-fold ± 0.04 vs. control, p<0.01) (Fig.1). In contrast, VKORC1 downregulation significantly promoted proliferation (EdU signal: 3.9 ± 1.7 vs. control, p<0.01) as well as viability (alamarBlue® absorbance: 1.07 ± 0.08 vs. control, p=0.04), and decreased ROS (0.88 ± 0.17 vs. control, p=0.03). Pro-inflammatory and ER-stress proteins were either unaltered or decreased after VKORC1 knockdown (e.g., GRP78: 0.89-fold, VCAM-1: 0.68-fold) (Fig.2). To further elucidate these findings, we will perform overexpression experiments and stable knockdown of the VKOR-enzymes. Conclusion VKORC1 and its isoenzyme VKORC1L1 exhibit divergent effects on endothelial cell inflammation. Further studies are warranted to shed light on the regulation of the enzymes to improve our understanding regarding vascular side effects of VKA treatment and beneficial effects of vitamin K supplementation.

Abstract 14843: Unveiling the Phenotype of Smooth Muscle Foam Cells in Human Atherosclerotic Lesions: Insights From Bulk and Single Cell RNA Sequencing

Background and Aims: Our previous studies of human coronary atherosclerosis and ApoE-/- mice indicated that at least 50% and ~70% of foam cells are of smooth muscle cell (SMC) origin, respectively. We also found that SMCs generate a distinct class of foam cells, due to several gene expression and regulatory differences compared to macrophage foam cells. In the current investigation we utilized transcriptomic approaches to identify and characterize the phenotype of SMC foam cells of human coronary plaques and in SMCs treated with aggregated LDL (ag-LDL). Methods: Sections of fresh human coronary artery were subjected to gentle digestion and the isolated cells used for single-cell RNA Sequencing (scRNA-Seq) (n=3) using 10X Genomics Chromium Single Cell 3’ Reagent Kits v3 Technology. Human vascular SMCs were treated with 100 μg/mL ag-LDL for 24 h (n=3) and stained with the fluorescent lipid probe BODIPY493/503. BODIPY high SMCs were collected and subjected to bulk RNA sequencing along with non-treated SMCs as control. Results: Single cell RNA sequencing of cells isolated from human coronary arteries followed by unsupervised Seurat-based clustering (R version 4.2.0) identified 15 distinct clusters including 8 SMC clusters with varying degrees of differentiation and macrophage foam and non-foam cells. The top 70 upregulated genes in ag-LDL treated SMCs were used to identify clusters corresponding to SMC foam cells in the scRNA-seq dataset. We found that these genes are mostly enriched in 2 clusters of less differentiated SMCs. SMC and macrophage foam cell clusters display distinct characteristics. SMC foam cell clusters exhibit upregulation of complement and coagulation cascades, as well as ECM-receptor interaction genes. In contrast, the macrophage foam cell cluster shows enrichment of proinflammatory genes, genes involved in the response to unfolded protein, and both pro- and anti-apoptotic genes. Conclusion: Our studies provide novel tools to investigate the nature of SMC foam cells in human atherosclerosis and may provide unique markers for SMC foam cells. Gaining a comprehensive insight of the significance and characteristics of SMC foam cells is crucial in elucidating their ultimate role and potential as a therapeutic target in atherosclerosis.

ADAMTS-7 deficiency attenuates thoracic aortic aneurysm and dissection in mice.

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening cardiovascular disease with severe extracellular matrix (ECM) remodeling that lacks efficient early stage diagnosis and nonsurgical therapy. A disintegrin and metalloproteinase with thrombospondin motif 7 (ADAMTS-7) is recognized as a novel locus for human coronary artery atherosclerosis. Previous work by us and others showed that ADAMTS-7 promoted atherosclerosis, postinjury neointima formation, and vascular calcification. However, whether ADAMTS-7 is involved in TAAD pathogenesis is unknown. We aimed to explore the alterations in ADAMTS-7 expression in human and mouse TAAD, and investigate the role of ADAMTS-7 in TAAD formation. A case-control study of TAAD patients (N = 86) and healthy participants (N = 88) was performed. The plasma ADAMTS-7 levels were markedly increased in TAAD patients within 24h and peaked in 7days. A TAAD mouse model was induced with 0.5% β-aminopropionitrile (BAPN) in drinking water. ELISA analysis of mouse plasma, Western blotting, and immunohistochemical staining of aorta showed an increase in ADAMTS-7 in the early stage of TAAD. Moreover, ADAMTS-7-deficient mice exhibited significantly attenuated TAAD formation and TAAD rupture-related mortality in both male and female mice, which was accompanied by reduced artery dilation and inhibited elastin degradation. ADAMTS-7 deficiency caused repressed inflammatory response and complement system activation during TAAD formation. An increase in plasma ADAMTS-7 is a novel biomarker for human TAAD. ADAMTS-7 deficiency attenuates BAPN-induced murine TAAD. ADAMTS-7 is a potential novel target for TAAD diagnosis and therapy. KEY MESSAGES: A case-control study revealed increased plasma ADAMTS-7 is a risk factor for TAAD. ADAMTS-7 was elevated in plasma and aorta at early stage of mouse TAAD. ADAMTS-7 knockout attenuated mouse TAAD formation and mortality in both sexes.

Validating human and mouse tissues commonly used in atherosclerosis research with coronary and aortic reference tissue: similarities but profound differences in disease initiation and plaque stability

ObjectiveCharacterization of the atherosclerotic process fully relies on histological evaluation and staging through a consensus grading system. So far, a head-to-head comparison of atherosclerotic process in experimental models and tissue resources commonly applied in atherosclerosis research with the actual human atherosclerotic process is missing. Material and MethodsAspects of the atherosclerotic process present in established murine atherosclerosis models and human carotid endarterectomy specimen were systematically graded using the modified American Heart Association histological classification (Virmani classification). Aspects were aligned with the atherosclerotic process observed in human coronary artery and aortic atherosclerosis reference tissues that were available through biobanks based on human tissue/organ donor material. ResultsApart from absent intraplaque hemorrhages in aortic lesions, the histological characteristics of the different stages of human coronary and aortic atherosclerosis are similar. Carotid endarterectomy samples all represent end-stage “fibrous calcified plaque” lesions, although secondary, progressive, and vulnerable lesions with gross morphologies similar to coronary/aortic lesions occasionally present along the primary lesions. For the murine lesions, clear histological parallels were observed for the intermediate lesion types (“pathological intimal thickening,” and “early fibroatheroma”). However, none of the murine lesions studied progressed to an equivalent of late fibroatheroma or beyond. Notable contrasts were observed for disease initiation: whereas disease initiation in humans is characterized by a mesenchymal cell influx in the intima, the earliest murine lesions are exclusively intimal, with subendothelial accumulation foam cells. A mesenchymal (and medial) response are absent. In fact, it is concluded that the stage of “adaptive intimal thickening” is absent in all mouse models included in this study. ConclusionsThe Virmani classification for coronary atherosclerosis can be applied for systematically grading experimental and clinical atherosclerosis. Application of this histological grading tool shows clear parallels for intermediate human and murine atherosclerotic lesions. However, clear contrasts are observed for disease initiation, and late stage atherosclerotic lesions. Carotid endarterectomy all represent end-stage fibrous calcified plaque lesions, although secondary earlier lesions may present in a subset of samples.

Peptide Vaccine Against ADAMTS-7 Ameliorates Atherosclerosis and Postinjury Neointima Hyperplasia.

The metalloprotease ADAMTS-7 (a disintegrin and metalloproteinase with thrombospondin type 1 motif 7) is a novel locus associated with human coronary atherosclerosis. ADAMTS-7 deletion protects against atherosclerosis and vascular restenosis in rodents. We designed 3 potential vaccines consisting of distinct B cell epitopic peptides derived from ADAMTS-7 and conjugated with the carrier protein KLH (keyhole limpet hemocyanin) as well as aluminum hydroxide as an adjuvant. Arterial ligation or wire injury was used to induce neointima in mice, whereas ApoE-/- and LDLR-/- (LDLR [low-density lipoprotein receptor]) mice fed a high-fat diet were applied to assess atherosclerosis. In addition, coronary stent implantation was performed on vaccine-immunized Bama miniature pigs, followed by optical coherence tomography to evaluate coronary intimal hyperplasia. A vaccine, ATS7vac, was screened out from 3 candidates to effectively inhibit intimal thickening in murine carotid artery ligation models after vaccination. As well, immunization with ATS7vac alleviated neointima formation in murine wire injury models and mitigated atherosclerotic lesions in both hyperlipidemic ApoE-/- and LDLR-/- mice without lowering lipid levels. Preclinically, ATS7vac markedly impeded intimal hyperplasia in swine stented coronary arteries, but without significant immune-related organ injuries. Mechanistically, ATS7vac vaccination produced specific antibodies against ADAMTS-7, which markedly repressed ADAMTS-7-mediated COMP (cartilage oligomeric matrix protein) and TSP-1 (thrombospondin-1) degradation and subsequently inhibited vascular smooth muscle cell migration but promoted re-endothelialization. ATS7vac is a novel atherosclerosis vaccine that also alleviates in-stent restenosis. The application of ATS7vac would be a complementary therapeutic avenue to the current lipid-lowering strategy for atherosclerotic disease.

Intracoronary Imaging of Vulnerable Plaque-From Clinical Research to Everyday Practice.

The introduction into clinical practice of intravascular imaging, including intravascular ultrasound (IVUS), optical coherence tomography (OCT) and their derivatives, allowed for the in vivo assessment of coronary atherosclerosis in humans, including insights into plaque evolution and progression process. Intravascular ultrasound, the most commonly used intravascular modality in many countries, due to its low resolution cannot assess many features of vulnerable plaque such as lipid plaque or thin-cap fibroatheroma. Thus, novel methods were introduced to facilitate this problem including virtual histology intravascular ultrasound and later on near-infrared spectroscopy and OCT. Howbeit, none of the currently used modalities can assess all known characteristics of plaque vulnerability; hence, the idea of combining different intravascular imaging methods has emerged including NIRS-IVUS or OCT-IVUS imaging. All of those described methods may allow us to identify the most vulnerable plaques, which are prone to cause acute coronary syndrome, and thus they may allow us to introduce proper treatment before plaque destabilization.

Abstract 12775: The Major Contribution and Characteristics of Smooth Muscle Cell Foam Cells in Human Atherosclerotic Lesions Based on Flow Cytometry and Single Cell RNA Sequencing

Background and Aims: Smooth muscle cells (SMCs) comprise the majority of cells within human atherosclerotic intima. Our previous study of human coronary atherosclerosis found that ≥50% of foam cells are of SMC origin and not primarily of macrophage origin as previously thought. In a recent investigation we reported that ~70% of all foam cells in ApoE-/- mice fed a Western Diet for 6 weeks are SMC-derived. In the current investigation we utilized flow cytometry and single-cell RNA sequencing to study the contribution and characteristics of SMC-derived foam cells in human atherosclerotic plaques. Hypothesis: SMCs comprise the majority of foam cells in human atherosclerosis and SMC foam cells have a unique gene expression pattern compared to macrophage foam cells. Methods: Formalin-fixed coronary and aortic samples were digested, stained with the lipid dye BODIPY and CD45 antibody and separated into CD45+ (leukocyte) and CD45- (non-leukocyte) foam cell and non-foam cell populations using flow cytometry. Pieces of fresh human coronary artery with adventitia removed were subjected to gentle digestion and isolated cells used for single-cell RNA Sequencing (n=3) using 10X Genomics Chromium Single Cell 3’ Reagent Kits v3 Technology. Results: Flow cytometric analysis indicates that approximately 65% of total foam cells of human coronary and aortic atherosclerotic lesions are of non-leukocyte origin. Unsupervised Seurat-based clustering (R version 4.2.0) singled out multiple cell clusters including SMCs, leukocytes, and endothelial cells in all 3 samples. Combining data resulted in identification of 15 distinct clusters including 8 SMC clusters ranging from well-differentiated to varying degrees of dedifferentiation. Combining multiple markers identified by in vitro and in vivo studies of SMC foam cells we were able to identify 2 possible SMC foam cell clusters with gene expression patterns distinct from macrophage foam cells. Conclusions: Our findings further identify SMCs as the major contributors of foam cells in atherosclerosis, and provide novel tools to investigate the nature of SMC foam cells in human atherosclerosis and their responses to anti-atherosclerotic therapies.

The resolvin D2 – GPR18 axis is expressed in human coronary atherosclerosis and transduces atheroprotection in apolipoprotein E deficient mice

Chronic inflammation in atherosclerosis reflects a failure in the resolution of inflammation. Pro-resolving lipid mediators derived from omega-3 fatty acids reduce the development of atherosclerosis in murine models. The aim of the present study was to decipher the role of the specialized proresolving mediator (SPM) resolvin D2 (RvD2) in atherosclerosis and its signaling through the G-protein coupled receptor (GPR) 18. The ligand and receptor were detected in human coronary arteries in relation to the presence of atherosclerotic lesions and its cellular components. Importantly, RvD2 levels were significantly higher in atherosclerotic compared with healthy human coronary arteries. Furthermore, apolipoprotein E (ApoE) deficient hyperlipidemic mice were treated with either RvD2 or vehicle in the absence and presence of the GPR18 antagonist O-1918. RvD2 significantly reduced atherosclerosis, necrotic core area, and pro-inflammatory macrophage marker expression. RvD2 in addition enhanced macrophage phagocytosis. The beneficial effects of RvD2 were not observed in the presence of O-1918. Taken together, these results provide evidence of atheroprotective pro-resolving signalling through the RvD2-GPR18 axis.

Abstract 195: Transcriptional Regulation Of Transcriptional Regulation Of Triggering Receptor Expressed On Myeloid Cells-1 By Low Shear Stress In A Three-dimensional Co-culture Of Coronary Artery Smooth Muscle Cells, Endothelial Cells, And Monocytes

Objectives: To identify transcriptional factors involved in the expression of Triggering Receptor Expressed on Myeloid Cells-1 (TREM-1) in response to low shear stress in an in-vitro model of coronary artery atherosclerosis. Methods: Human coronary artery smooth muscle cells were mixed with neutralized type I collagen solution and plated on glass coverslips. The human coronary artery endothelial cells (HCAECs) were then plated on top of the collagen gels followed by plating monocytes (THP-1 cells) on top of the HCAECs. After 48 h, the co-culture was treated with or without low shear stress (LSS, 5±3 dyne/cm 2 ) using the Flexcell Streamer for 30 min. Protein and mRNA of TREM-1 expression was assessed by immunofluorescence staining and real time RT-PCR. The expression of transcriptional factors involved in the expression of TREM-1 was assessed by ChIP assay. Results: LSS significantly stimulated TREM-1 expression as evidenced by IF staining and mRNA expression (fold increase vs control: 43.2 ± 9.7, Fig 1A and 1B ). ChIP assay demonstrated that, under control condition (no flow), NF-κB (p65), PU.1 and activation transcription factor 2 (ATF2) bound to TREM-1 promoter region 2, but not to region 1 ( Fig 2A ). In response to LSS for 30 min, however, binding of the NF-κB (p65), PU.1 and ATF2 to TREM-1 promoter region 2 was significantly enhanced; furthermore, LSS treatment induced binding of NF-κB (p65), PU.1 and ATF2 to TREM-1 promoter region 1 ( Fig 2B) . Conclusions: Transcriptional factors NF-κB (p65), PU.1 and ATF2 are critically involved in the TREM-1 expression in response to LSS stimulation in an in-vitro model of human coronary artery atherosclerosis.

Plasma Ceramide Levels Are Elevated in Patients With Early Coronary Atherosclerosis and Endothelial Dysfunction.

BackgroundElevated plasma ceramides are independent predictors of cardiovascular disease and mortality in patients with advanced epicardial coronary artery disease. Our understanding of plasma ceramides in early epicardial coronary artery disease, however, remains limited. We examined the role of plasma ceramides in early coronary atherosclerosis characterized by coronary endothelial dysfunction.Methods and ResultsParticipants presenting with chest pain and nonobstructive epicardial coronary artery disease underwent coronary endothelial function. Patients (n=90) demonstrated abnormal coronary endothelial function with acetylcholine (≥20% decrease in coronary artery diameter or ≤50% increase in coronary blood flow). A total of 30 controls had normal coronary endothelial function. Concentrations of plasma ceramide 18:0 (P=0.038), 16:0 (P=0.021), and 24:0 (P=0.019) differed between participants with normal and abnormal coronary endothelial function. Ceramide 24:0 (odds ratio [OR], 2.23 [95% CI, 1.07–4.66]; P=0.033) and 16:0 (OR, 1.91×106 [95% CI, 11.93–3.07×1011]; P=0.018) were independently associated with coronary endothelial dysfunction. Among participants with endothelium‐dependent coronary dysfunction (n=78), ceramides 16:0 (OR, 5.17×105 [95% CI, 2.83–9.44×1010]; P=0.033), 24:0 (OR, 2.98 [95% CI, 1.27–7.00]; P=0.012), and 24:1/24:0 (OR, 4.39×10−4 [95% CI, 4×10−7–0.48]; P=0.030) were more likely to be elevated.ConclusionsThe current study demonstrated an association between increased circulating ceramide levels and coronary endothelial dysfunction in the absence of epicardial coronary artery disease. This study supports the role of plasma ceramides as a potential biomarker or a therapeutic target for early coronary atherosclerosis in humans.

Identification of Potential Ferroptosis-Related Biomarkers and Immune Infiltration in Human Coronary Artery Atherosclerosis.

ObjectiveFerroptosis is a specific subtype of programmed cell death, which plays an essential role in the immune-associated disease, atherosclerosis (AS). The purpose of this study was to identify potential ferroptosis-related gene biomarkers and its association with immune infiltration characteristics in atherosclerosis with bioinformatics methods.MethodsDifferentially expressed genes (DEGs) between AS and control groups were screened from GSE40231, analyzed for functional enrichment and then intersected with ferroptosis-related genes. Then, a random forest model was constructed based on these differentially expressed ferroptosis-related genes (DE-FRGs) and validated with dataset GSE132651. The performance of the models was evaluated with the area under receiver operating characteristic curves (AUC). Finally, we analyzed the correlation between DE-FRGs above and the characteristics of immune infiltration via CIBERSORT method.ResultsSix DE-FRGs (IL6, ANGPTL7, CDKN1A, AKR1C3, NOX4 and VLDLR) were detected based on dataset of GSE40231. Furthermore, a random forest model was constructed based on them with a compelling diagnostic performance of AUC = 0.8974 in the validation dataset GSE132651. In addition, the proportion of follicular helper T (Tfh) cells was significantly higher in AS group (P < 0.001). And we found significant correlation relationship between Tfh and expression level of ANGPTL7 (R = 0.35, P < 0.01), CDKN1A (R = 0.4, P < 0.0001), AKR1C3 (R = 0.64, P < 0.0001), NOX4 (R = 0.32, P < 0.01) and VLDLR (R = −0.43, P < 0.0001).ConclusionThis study identified 6 DE-FRGs and validated a predicted model for the early prediction of AS, which also proved the close relationship between ferroptosis and immunity in the pathogenesis of AS.

High-dimensional Single-cell Analysis Delineates Peripheral Immune Signature of Coronary Atherosclerosis in Human Blood

Rationale: Pathogenesis of human coronary atherosclerosis is tightly associated with the imbalance of inflammation and resolution in the local immune microenvironment of AS plaques. However, how the peripheral immune system dynamically changes along with disease progression in humans remains unclear. As a result, the minimally-invasive clinical biomarkers that can sensitively distinguish different stages of human coronary atherosclerosis are still lacking.Methods: We performed single-cell Cytometry by Time-Of-Flight (CyTOF) analyses to comprehensively profile the compositions and phenotypes of CD45+ cells derived from 83 human peripheral blood samples with two independent antibody-staining panels (T cell panel and myeloid cell panel). Clinical associations between the frequencies of peripheral immune cell subsets with AS plaque burdens of coronary arteries (Gensini score) and serum lipids were also examined. By integrating immune and clinical features, we established novel CVD risk prediction models to stratify patients in different disease stages.Results: We revealed the disease stage-associated peripheral immune features for patients with coronary atherosclerosis (CAS) and atherosclerotic cardiovascular disease (ASCVD), and also identified the specific peripheral immune cell subsets that were tightly associated with the disease severity of coronary arteries (Gensini score). By integrating these peripheral immune signatures with clinical features, we have established a disease progression prediction (DPP) model that could precisely discriminate CAS patients from ASCVD patients with high prediction accuracy (ROC-AUC = 0.88).Conclusion: The progression of coronary atherosclerosis is accompanied by significant alterations of the peripheral immune system, including the changes in the distributions as well as phenotypic functions of specific immune cell subsets. The indicated stage-specific peripheral immune signatures thus become promising minimally-invasive liquid biomarkers that could help to potentially diagnose and monitor the CVD progression in humans.

Verification of ferroptosis and pyroptosis and identification of PTGS2 as the hub gene in human coronary artery atherosclerosis

Ferroptosis and pyroptosis have not been fully studied in atherosclerosis. We aimed to investigate the expression of ferroptosis-related and pyroptosis-related proteins in human coronary arteries and analyse correlation with severity of atherosclerosis and clarify the interactions between proteins and possible mechanisms of atherosclerosis. 40 human coronary artery specimens were employed. The atherosclerotic lesions were characterized by Haematoxylin and Eosin (H&E) staining. The expression of prostaglandin-endoperoxide synthase 2 (PTGS2), anti-acyl-CoA synthetase long-chain family member 4 (ACSL4), glutathione peroxidase 4 (GPX4), caspase-1, and NOD-like receptor protein 3 (NLRP3) were analysed by immunohistochemical assay. Correlations between expression of proteins and severity of atherosclerosis were assessed using Spearman correlation analysis. Bioinformatic and coexpression analyses were performed to study the possible pathways and interactions. In the present study, PTGS2, ACSL4, caspase-1, and NLRP3, were upregulated, while GPX4 was downregulated in the advanced stages of atherosclerosis. The severity of atherosclerosis was positively associated with the expression of PTGS2, ACSL4, caspase-1, and NLRP3 and negatively associated with the expression of GPX4. Biological processes of lipid metabolism and inflammation and C-type lectin receptor signaling pathway were enriched. The five proteins interacted with each other directly or indirectly and PTGS2 might be the hub gene of atherosclerosis. Ferroptosis and pyroptosis may regulate the occurrence and development of atherosclerosis. These findings may shed light on new ideas and potential targets for the prevention and treatment of coronary artery atherosclerosis and the proteins may be used as biomarkers for the severity of atherosclerosis.

The Degradation of G3BP2 by Trim-away Method Inhibits Oscillatory Shear Stress induced Endothelial Cell Inflammation

Progress in medical science has shown that cardiovascular pathogenesis is a complex disease with multiple underlying factors. Stress factors such as oxidative stress and oscillatory shear stress (OSS) play a crucial role in the occurrence and development of atherosclerosis as the major cause of cardiovascular diseases (CVD). However, study related the effect of stress on the development of human coronary atherosclerosis is not yet fully understood. Ras-GTPase-activating protein SH3 domain-binding proteins 2 (G3BP2) are multi-functional RNA binding proteins in which biomechanically sensitive gene that known important in cancer progression. Here in this study, we further explore the roles of G3BP2 protein especially their relation with atherosclerosis diseases, by investigating the G3BP2 regulation under biomechanical stress stimuli follows with the strategy of exploring the effect of G3BP2 disruption in endothelial cells by the application of new protein depletion technology called Trim-away. The result showed that oxidative stress and oscillatory shear stress (OSS) stimuli activated the expression of G3BP2 protein in primary endothelial cells. Moreover, the western blot analysis revealed that degradation of G3BP2 protein using Trim-away in endothelial cells induced OSS inhibits the release of the pro-inflammatory cytokines (VCAM-1 and ICAM-1). The compelling evidence demonstrated that suppression of G3BP2 protein expression in HUVECs potentially inhibits the development of atherosclerosis by decreased endothelial inflammation response.

Migration of OxLDL+ Macrophage Phenotypes from Pericoronary Adipose Tissue to Coronary Intima: A Possible Mechanism for Human Coronary Atherosclerosis

Background: We previously found that oxidized low-density lipoprotein (oxLDL), a core atherogenic protein, is stored in human pericoronary adipose tissue (PCAT) and macrophages residing in PCAT accumulate oxLDL. Here, we aimed to identify whether and how the macrophage phenotypes transport oxLDL from PCAT to the coronary intima.