Implications For Atherosclerosis Research Articles

Inflammaging, a targetable pathway for preventing cardiovascular diseases.

Inflammaging, characterized by persistent chronic inflammation in older adults, has emerged as a critical factor linked to age-related diseases such as cardiovascular diseases (CVDs), metabolic disorders, and cognitive decline, which collectively contribute to the leading causes of death globally. Elevated levels of cytokines, chemokines, and others inflammatory mediators characterize inflammaging and serve as indicators of biological age. Among the causes of inflammaging, deterioration of the immune system, mitochondrial dysfunction, dysbiosis, accumulation of DAMPs, together with genetic or epigenetic factors, contribute to inflammaging not only in CVD but also in other age-related conditions. This review examines the causes and consequences of inflammaging, particularly its implications for atherosclerosis and heart failure with preserved ejection fraction (HFpEF) and explores potential strategies to mitigate it in the onset of CVD.

The protective effects of annexin A1 against oxidized-LDL-induced monocytes adhesion to endothelial cells: implication in atherosclerosis.

Oxidized low-density lipoprotein (ox-LDL)-associated endothelial dysfunction is a critical factor in the initiation and progression of Atherosclerosis (AS). Annexin A1 is an important member of the annexin family. Despite its wide range of biological functions across various tissues and cells, the role of Annexin A1 in AS remains largely unexplored. In this study, we demonstrate that Annexin A1 treatment effectively reduced the expression of LOX-1 at both the mRNA and protein levels in HUVECs exposed to ox-LDL. Annexin A1 also ameliorated oxidative stress (OS) by decreasing mitochondrial ROS levels and restoring reduced GSH levels. Moreover, Annexin A1 decreased the expression of pro-inflammatory cytokines, including IL-6 and MCP-1. Importantly, Annexin A1 inhibited ox-LDL-induced expressions of the endothelial adhesion molecules, such as E-selectin and VCAM-1 in HUVECs, which leads to reduced attachment of THP-1 monocytes to HUVECs. Mechanically, we found that Annexin A1 reversed the expression of KLF2 against ox-LDL mediated by the PI3K/Akt axis. Notably, the silencing of KLF2 abrogated the protective effects of Annexin A1 on E-selectin and VCAM-1 expression and the attachment of THP-1 monocytes to HUVECs. Our findings suggest that Annexin A1 is a potential therapeutic agent for atherosclerosis, offering a novel approach to mitigate endothelial dysfunction and inflammation.

The double-edged impact of obesity on cancer risk and treatment response: implications for atherosclerosis?

The double-edged impact of obesity on cancer risk and treatment response: implications for atherosclerosis?

Bezafibrate mitigates oxidized-low density lipoprotein (ox-LDL)-induced the attachment of monocytes to endothelial cells: An implication in atherosclerosis.

Oxidized forms of low-density lipoproteins (ox-LDL)-associated endothelial dysfunction and subsequent monocyte adhesion play an important role in the development of atherosclerosis (AS). Bezafibrate (BEZ) is a peroxisome proliferator-activated receptor (pan-PPAR) agonist licensed as a hypolipidemic drug. However, the effects of BEZ on endothelial dysfunction are less reported. In this study, we aim to investigate the protective effects of BEZ on ox-LDL-challenged vascular endothelial cells to evaluate its potential value in treating AS. Human aortic endothelial cells (HAECs) and THP-1 cells were used to establish an In Vitro AS model. Cell Counting Kit-8 (CCK-8) assay, Real-time PCR, Western blot analysis, and Enzyme-linked immunosorbent assay (ELISA) were used to test the data. As expected, treatment with BEZ suppressed the expression of vascular endothelial growth factor A (VEGF-A), tissue factor (TF), Interleukin 12 (IL-12), tumor necrosis factor (TNF-α), and monocyte chemoattractant protein-1 (MCP-1). BEZ was also found to inhibit ox-LDL-induced expression of the endothelial adhesion molecules vascular cellular adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) in HAECs. Correspondingly, BEZ prevented attachment of THP-1 monocytes to ox-LDL-incubated HAECs. Mechanically, BEZ was found to prevent NF-κB activation by reducing the levels of nuclear NF-κB p65 and inhibiting luciferase activity of NF-κB. Our study revealed the pharmacological function of BEZ in protecting endothelial dysfunction against ox-LDL, which may provide valuable insight for the clinical application of BEZ.

Cardiolipin in Pathology: Implications in Atherosclerosis

Cardiolipin in Pathology: Implications in Atherosclerosis

The emerging crosstalk between atherosclerosis-related microRNAs and Bermuda triangle of foam cells: Cholesterol influx, trafficking, and efflux

In atherosclerosis, the gradual buildup of lipid particles into the sub-endothelium of damaged arteries leads to numerous lipid alterations. The absorption of these modified lipids by monocyte-derived macrophages in the arterial wall leads to cholesterol accumulation and increases the likelihood of foam cell formation and fatty streak, which is an early characteristic of atherosclerosis. Foam cell formation is related to an imbalance in cholesterol influx, trafficking, and efflux. The formation of foam cells is heavily regulated by various mechanisms, among them, the role of epigenetic factors like microRNA alteration in the formation of foam cells has been well studied. Recent studies have focused on the potential interplay between microRNAs and foam cell formation in the pathogenesis of atherosclerosis; nevertheless, there is significant space to progress in this attractive field. This review has focused to examine the underlying processes of foam cell formation and microRNA crosstalk to provide a deep insight into therapeutic implications in atherosclerosis.

Healthful nutrition decreases vulnerability to environmental pollutant-induced inflammatory diseases: Implications in atherosclerosis

Background and Aims : Multifactorial interactions linked to exacerbated disease pathologies of atherosclerosis and other CVDs include pro-inflammatory chemical and non-chemical stressor. Many environmental pollutants or chemical stressors with pro-oxidant and pro-inflammatory properties include persistent organic pollutants, such as polychlorinated biphenyls (PCBs). Dioxin-like PCBs can increase endothelial cell dysfunction and activation, leading to induction of inflammatory genes. Recent data suggest that genetic and lifestyle factors are independently associated with susceptibility to CVD.

3β-Hydroxy-5β-hydroxy-B-norcholestane-6β-carboxaldehyde (SEC-B) Induces Proinflammatory Activation of Human Endothelial Cells Associated with Nitric Oxide Production and Endothelial Nitric Oxide Synthase/Caveolin-1 Dysregulation.

Oxysterols are a family of 27-carbon cholesterol oxidation derivatives found in low-density lipoproteins (LDLs) and atherosclerotic plaques where they trigger several biological responses involved in the initiation and progression of atherosclerosis. Several pieces of evidence suggest that oxysterols contribute to endothelial dysfunction (ED) due to their ability to alter membrane fluidity and cell permeability leading to inflammation, oxidative stress and apoptosis. The present study aimed to investigate the molecular events occurring in human microvascular endothelial cells (HMEC-1) in response to autoxidation-generated 3β-hydroxy-5β-hydroxy-B-norcholestane-6β-carboxaldehyde (SEC-B) exposure. Our results highlight that SEC-B rapidly activates HMEC-1 by inducing oxidative stress, nitric oxide (NO) production and pro-inflammatory cytokine release. Exposure to SEC-B up to 24 h results in persistent accumulation of the vasodilator NO paralleled by an upregulation of the endothelial nitric oxide synthase (eNOS) enzyme and downregulation of Caveolin-1 (Cav-1) protein levels. Moreover, reduced expression and extracellular release of the vasoconstrictor factor endothelin-1 (ET-1) are observed. Furthermore, SEC-B stimulates the expression of the cytokines interleukin-6 (IL-6) and tumor necrosis factor-like weak inducer of apoptosis (TWEAK). This proinflammatory state leads to increased monocyte recruitment on activated HMEC-1 cells. Our findings add new knowledge on the role of SEC-B in ED and further support its potential implication in atherosclerosis.

Candida albicans Induces Foaming and Inflammation in Macrophages through FABP4: Its Implication for Atherosclerosis

Abstract Atherosclerosis is a chronic degenerative disorder characterized by lipid-dense plaques and low-grade inflammation affecting arterial walls. Foamy macrophages are important in the formation of atherosclerotic plaques and the induction of low-grade inflammation. Candida albicans is the major cause of candidiasis in immunocompromised patients, including those with diabetes mellitus. However, the role played by C. albicans in macrophage foaming and the associated inflammation is poorly understood. We investigated whether C. albicans induces foaming along with inflammation in macrophages and, if so, by which mechanism(s). We incubated THP-1 macrophages with heat-killed C. albicans (HKCA). HKCA-induced lipid accumulation in macrophages along with increased expression of inflammatory markers, including CD11b and CD11c or expression and secretion of IL-1β. HKCA also increased the expression of PPAR, CD36, and FABP4 in macrophages. Mechanistically, we found that the foamy and inflammatory macrophage phenotype induced by HKCA requires FABP4 because disruption of FABP4 in macrophages either by chemical inhibitor BMS309404 or small interfering RNA (siRNA) abrogated foam cell formation and expression of inflammatory markers CD11b, CD11c, and IL-1β. Furthermore, HKCA-treated macrophages displayed high expression and secretion of MMP-9. Inhibition of FABP4 resulted in suppression of HCKA-induced MMP-9 production. Overall, our results demonstrate that C. albicans induces foam cell formation, inflammation, and MMP-9 expression in macrophages via the upregulation of FABP4, which may constitute a novel therapeutic target for treating C. albicans-induced atherosclerosis. Supported by Kuwait Foundation for the Advancement of Sciences (KFAS) (RA CB-2019-002)

Endothelial dysfunction in acute and long standing COVID−19: A prospective cohort study

BackgroundCoronavirus disease-19 (COVID-19) is implicated by active endotheliitis, and cardiovascular morbidity. The long-COVID-19 syndrome implications in atherosclerosis have not been elucidated yet. We assessed the immediate, intermediate, and long-term effects of COVID-19 on endothelial function. MethodsIn this prospective cohort study, patients hospitalized for COVID-19 at the medical ward or Intensive Care Unit (ICU) were enrolled and followed up to 6 months post-hospital discharge. Medical history and laboratory examinations were performed while the endothelial function was assessed by brachial artery flow-mediated dilation (FMD). Comparison with propensity score-matched cohort (control group) was performed at the acute (upon hospital admission) and follow-up (1 and 6 months) stages. ResultsSeventy-three patients diagnosed with COVID-19 (37% admitted in ICU) were recruited. FMD was significantly (p < 0.001) impaired in the COVID-19 group (1.65 ± 2.31%) compared to the control (6.51 ± 2.91%). ICU-treated subjects presented significantly impaired (p = 0.001) FMD (0.48 ± 1.01%) compared to those treated in the medical ward (2.33 ± 2.57%). During hospitalization, FMD was inversely associated with Interleukin-6 and Troponin I (p < 0.05 for all). Although, a significant improvement in FMD was noted during the follow-up (acute: 1.75 ± 2.19% vs. 1 month: 4.23 ± 2.02%, vs. 6 months: 5.24 ± 1.62%; p = 0.001), FMD remained impaired compared to control (6.48 ± 3.08%) at 1 month (p < 0.001) and 6 months (p = 0.01) post-hospital discharge. ConclusionCOVID-19 patients develop a notable endothelial dysfunction, which is progressively improved over a 6-month follow-up but remains impaired compared to healthy controls subjects. Whether chronic dysregulation of endothelial function following COVID-19 could be accompanied by a residual risk for cardiovascular and thrombotic events merits further research.

Adaptive Immune Response Signaling Is Suppressed in Ly6Chigh Monocyte but Upregulated in Monocyte Subsets of ApoE-/- Mice - Functional Implication in Atherosclerosis.

RationaleInflammatory monocyte (MC) subset differentiation is a major feature in tissue inflammatory and atherosclerosis. The underlying molecular mechanism remains unclear.ObjectiveThis study aims to explore molecule targets and signaling which determinate immunological features in MC subsets.Methods and ResultsBlood Ly6Chigh and Ly6Clow MC subsets from control and ApoE -/- mice were isolated by flow cytometry sorting and subjected for bulk high-throughput RNA-sequencing. Intensive bioinformatic studies were performed by analyzing transcriptome through four pairs of comparisons: A) Ly6Chigh vs Ly6Clow in control mice; B) Ly6Chigh vs Ly6Clow in ApoE-/- mice; C) ApoE-/- Ly6Chigh vs control Ly6Chigh MC; D) ApoE-/- Ly6Clow vs control Ly6Clow MC. A total of 80 canonical pathways and 16 enriched pathways were recognized by top-down analysis using IPA and GSEA software, and further used for overlapping analysis. Immunological features and signaling were assessed on four selected functional groups, including MHCII, immune checkpoint, cytokine, and transcription factor (TF). Among the total 14578 significantly differentially expressed (SDE) genes identified though above four comparison, 1051 TF and 348 immunological genes were discovered. SDE immunological genes were matched with corresponding upstream SDE TF by IPA upstream analysis. Fourteen potential transcriptional axes were recognized to modulate immunological features in the Ly6C MC subset. Based on an intensive literature search, we found that the identified SDE immune checkpoint genes in Ly6Chigh MC are associated with pro-inflammatory/atherogenic balance function. Immune checkpoint genes GITR, CTLA4, and CD96 were upregulated in Ly6Clow MC from all mice and presented anti-inflammatory/atherogenic features. Six cytokine genes, including Ccl2, Tnfsf14, Il1rn, Cxcl10, Ccl9, and Cxcl2, were upregulated in Ly6Chigh MC from all mice and associated with pro-inflammatory/atherogenic feature. Cytokine receptor gene Il12rb2, Il1r1, Il27ra, Il5ra, Ngfr, Ccr7, and Cxcr5 were upregulated in Ly6Clow MC from all mice and presented anti-inflammatory/atherogenic features. MHCII genes (H2-Oa, H2-DMb2, H2-Ob, H2-Eb2, H2-Eb1, H2-Aa, and Cd74) were elevated in Ly6Clow MC from all mice. ApoE -/- augmented pro-atherogenic/inflammatory and antigen-presenting cells (APC) feature in both subsets due to elevated expression of cytokine genes (Cxcl11, Cntf, Il24, Xcl, Ccr5, Mpl, and Acvr2a) and MHCII gene (H2-Aa and H2-Ea-ps). Finally, we modeled immunological gene expression changes and functional implications in MC differentiation and adaptive immune response for MC subsets from control and ApoE-/- mice.ConclusionsLy6Chigh MC presented pro-inflammatory/atherogenic features and lower APC potential. Ly6Clow MC displayed anti-inflammatory/atherogenic features and higher APC potential. ApoE -/- confers upon both subsets with augmented pro-atherogenic/inflammatory function and APC potential.

Perivascular adipose tissue-derived nitric oxide compensates endothelial dysfunction in aged pre-atherosclerotic apolipoprotein E-deficient rats

Background and aimsAtherosclerosis is a major contributor to global mortality and is accompanied by vascular inflammation and endothelial dysfunction. Perivascular adipose tissue (PVAT) is an established regulator of vascular function with emerging implications in atherosclerosis. We investigated the modulation of aortic relaxation by PVAT in aged rats with apolipoprotein E deficiency (ApoE−/−) fed a high-fat diet as a model of early atherosclerosis. Methods and resultsApoE−/− rats (N = 7) and wild-type Sprague-Dawley controls (ApoE+/+, N = 8) received high-fat diet for 51 weeks. Hyperlipidemia was confirmed in ApoE−/− rats by elevated plasma cholesterol (p < 0.001) and triglyceride (p = 0.025) levels. Early atherosclerosis was supported by increased intima/media thickness ratio (p < 0.01) and ED1-positive macrophage influx in ApoE−/− aortic intima (p < 0.001). Inflammation in ApoE−/− PVAT was characteristic by an increased [18F]FDG uptake (p < 0.01), ED1-positive macrophage influx (p = 0.0003), mRNA expression levels of CD68 (p < 0.001) and IL-1β (p < 0.01), and upregulated iNOS protein (p = 0.011). The mRNAs of MCP-1, IL-6 and adiponectin remained unchanged in PVAT. Aortic PVAT volume measured with micro-PET/CT was increased in ApoE−/− rats (p < 0.01). Maximal endothelium-dependent relaxation (EDR) to acetylcholine in ApoE−/− aortic rings without PVAT was severely impaired (p = 0.012) compared with controls, while ApoE−/− aortic rings with PVAT showed higher EDR than controls. All EDR responses were blocked by L-NMMA and the expression of eNOS mRNA was increased in ApoE−/− PVAT (p = 0.035). ConclusionUsing a rat ApoE−/− model of early atherosclerosis, we capture a novel mechanism by which inflammatory PVAT compensates severe endothelial dysfunction by contributing NO upon cholinergic stimulation.

Candida albicans Induces Foaming and Inflammation in Macrophages through FABP4: Its Implication for Atherosclerosis.

Atherosclerosis is a chronic degenerative disorder characterized by lipid-dense plaques and low-grade inflammation affecting arterial walls. Foamy macrophages are important in the formation of atherosclerotic plaques and the induction of low-grade inflammation. The presence of lipid-laden macrophages has occurred in infections caused by opportunistic pathogens. Candida albicans is the major cause of candidiasis in immunocompromised patients, including those with diabetes mellitus. However, the role played by C. albicans in macrophage foaming and the associated inflammation is poorly understood. We investigated whether C. albicans induces foaming along with inflammation in macrophages and, if so, by which mechanism(s). We incubated THP-1 macrophages with heat-killed C. albicans (HKCA). HKCA-induced lipid accumulation in macrophages along with increased expression of inflammatory markers, including CD11b and CD11c or expression and secretion of IL-1β. HKCA also increased the expression of PPARγ, CD36, and FABP4 in macrophages. Mechanistically, we found that the foamy and inflammatory macrophage phenotype induced by HKCA requires FABP4 because disruption of FABP4 in macrophages either by chemical inhibitor BMS309404 or small interfering RNA (siRNA) abrogated foam cell formation and expression of inflammatory markers CD11b, CD11c, and IL-1β. Furthermore, HKCA-treated macrophages displayed high expression and secretion of MMP-9. Inhibition of FABP4 resulted in suppression of HCKA-induced MMP-9 production. Overall, our results demonstrate that C. albicans induces foam cell formation, inflammation, and MMP-9 expression in macrophages via the upregulation of FABP4, which may constitute a novel therapeutic target for treating C. albicans-induced atherosclerosis.

Lysophosphatidylcholine induces oxidative stress in human endothelial cells via NOX5 activation - implications in atherosclerosis.

The mechanisms involved in NOX5 activation in atherosclerotic processes are not completely understood. The present study tested the hypothesis that lysophosphatidylcholine (LPC), a proatherogenic component of oxLDL, induces endothelial calcium influx, which drives NOX5-dependent reactive oxygen species (ROS) production, oxidative stress, and endothelial cell dysfunction. Human aortic endothelial cells (HAEC) were stimulated with LPC (10-5 M, for different time points). Pharmacological inhibition of NOX5 (Melittin, 10-7 M) and NOX5 gene silencing (siRNA) was used to determine the role of NOX5-dependent ROS production in endothelial oxidative stress induced by LPC. ROS production was determined by lucigenin assay and electron paramagnetic spectroscopy (EPR), calcium transients by Fluo4 fluorimetry, and NOX5 activity and protein expression by pharmacological assays and immunoblotting, respectively. LPC increased ROS generation in endothelial cells at short (15 min) and long (4 h) stimulation times. LPC-induced ROS was abolished by a selective NOX5 inhibitor and by NOX5 siRNA. NOX1/4 dual inhibition and selective NOX1 inhibition only decreased ROS generation at 4 h. LPC increased HAEC intracellular calcium, important for NOX5 activation, and this was blocked by nifedipine and thapsigargin. Bapta-AM, selective Ca2+ chelator, prevented LPC-induced ROS production. NOX5 knockdown decreased LPC-induced ICAM-1 mRNA expression and monocyte adhesion to endothelial cells. These results suggest that NOX5, by mechanisms linked to increased intracellular calcium, is key to early LPC-induced endothelial oxidative stress and pro-inflammatory processes. Since these are essential events in the formation and progression of atherosclerotic lesions, the present study highlights an important role for NOX5 in atherosclerosis.

The role of high-density lipoprotein in the regulation of the immune response: implications for atherosclerosis and autoimmunity.

Inflammation and immune dysfunction have been increasingly recognized as crucial mechanisms in atherogenesis. Modifications in cell lipid metabolism, plasma dyslipidaemia and particularly low high-density lipoprotein (HDL) levels occur both in atherosclerosis and in autoimmune rheumatic diseases (which are strongly associated with an increased risk of atherosclerosis), suggesting the presence of a crucial link. HDL, the plasma lipoprotein responsible for reverse cholesterol transport, is known for its several protective effects in the context of atherosclerosis. Among these, HDL immunomodulatory effects are possibly the less understood. Through the efflux of cholesterol from plasma cell membranes with the consequent disruption of lipid rafts and the interaction with the cholesterol transporters present in the plasma membrane, HDL affects both the innate and adaptive immune responses. Animal and human studies have demonstrated a predominance of HDL anti-inflammatory effects, despite some pro-inflammatory actions having also been reported. The HDL role on the modulation of the immune response is further suggested by the detection of low levels together with a dysfunctional HDL in patients with autoimmune diseases. Here, we review the current knowledge of the immune mechanisms of atherosclerosis and the modulatory effects HDL may have on them.

Bioactive Sphingolipids as Major Regulators of Coronary Artery Disease

Atherosclerosis is the deposition of plaque in the main arteries. It is an inflammatory condition involving the accumulation of macrophages and various lipids (low-density lipoprotein [LDL] cholesterol, ceramide, S1P). Moreover, endothelial cells, macrophages, leukocytes, and smooth muscle cells are the major players in the atherogenic process. Sphingolipids are now emerging as important regulators in various pathophysiological processes, including the atherogenic process. Various sphingolipids exist, such as the ceramides, ceramide-1-phosphate, sphingosine, sphinganine, sphingosine-1-phosphate (S1P), sphingomyelin, and hundreds of glycosphingolipids. Among these, ceramides, glycosphingolipids, and S1P play important roles in the atherogenic processes. The atherosclerotic plaque consists of higher amounts of ceramide, glycosphingolipids, and sphingomyelin. The inhibition of the de novo ceramide biosynthesis reduces the development of atherosclerosis. S1P regulates atherogenesis via binding to the S1P receptor (S1PR). Among the five S1PRs (S1PR1-5), S1PR1 and S1PR3 mainly exert anti-atherosclerotic properties. This review mainly focuses on the effects of ceramide and S1P via the S1PR in the development of atherosclerosis. Moreover, it discusses the recent findings and potential therapeutic implications in atherosclerosis.

Quantification of glycoproteins by nuclear magnetic resonance associated with preclinical carotid atherosclerosis in patients with type 1 diabetes

Background and aimsGlycoproteins play a key role in inflammatory and cardiometabolic processes. Their implication in atherosclerosis in type 1 diabetes (T1D) is unknown. We assessed the relationships between classic inflammatory markers, glycoproteins measured by nuclear magnetic resonance (1H-NMR), and preclinical atherosclerosis in these patients. Methods and resultsWe selected patients with T1D, without cardiovascular disease (CVD), with: age ≥40 years, nephropathy (micro/macroalbuminuria), or ≥10 years of evolution with another risk factor. The presence of plaque (intima-media thickness >1.5 mm) was determined by ultrasonography. Concentrations of high-sensitive C-reactive protein (hsCRP), circulating leukocytes (classical inflammation markers) and 1H-NMR-glycoproteins (GlycA, GlycB, GlycF, and the height/width [H/W] ratios of GlycA and GlycB) were determined. We included 189 patients (58% male, age 47.0 [40.7–55.2] years). Thirty-five percent presented plaques (22%, ≥2 plaques). There was no association between hsCRP or leukocytes and atherosclerosis. However, in age- and sex-adjusted models, GlycA, GlycF, and the H/W ratios of GlycA and GlycB gradually increased with the number of plaques (0, 1, ≥2 plaques) only in patients without statins (p < 0.05), with no association in patients receiving this drug (p for interaction <0.05; in ≥2 plaques). Finally, in models adjusted for other classical and T1D-specific risk factors, GlycA and GlycB H/W ratios remained associated with carotid plaque (OR 1.39 [1.12–1.90] and OR 6.89 [1.85–25.62], respectively). ConclusionIn T1D individuals without lipid-lowering treatment, 1H-NMR-glycoproteins were independently associated with the presence and amount of carotid atherosclerosis, unlike other classical inflammatory markers. Further studies are needed to ascertain their utility as CVD biomarkers.

Phoenixin-20 Prevents ox-LDL-Induced Attachment of Monocytes to Human Aortic Endothelial Cells (HAECs): A Protective Implication in Atherosclerosis.

The exact cause of atherosclerosis is not known, and therefore, the current treatment options are limited. The activation of endothelial cells by oxidized low-density lipoprotein (ox-LDL) plays a key role in the initiation and progression of atherosclerosis. Phoenixin-20 is one of the newly identified neuropeptides with pleiotropic effects in the regulation of reproduction and other biological functions. G-protein receptor-coupled 173 (GPR173) is the putative receptor of Phoenixin-20. In the present study, we show that endothelial GPR173 is repressed upon ox-LDL stimulation in human aortic endothelial cells (HAECs). We further elaborate on the hypothesis that GPR173 could be involved in the pathogenesis of atherosclerosis through a series of experiments. Our results indicate that ox-LDL remarkably triggers the increase of ROS, NOX-4, pro-inflammatory cytokines IL-1β, IL-8, and MCP-1 expression, as well as adhesion molecules ICAM-1 and VCAM-1 release. However, the agonism of GPR173 using Phoenixin-20 significantly ameliorates all of these harmful effects from ox-LDL by suppressing the NF-κB pathway. Furthermore, we show that agonism of GPR173 by Phoenixin-20 prevents the attachment of monocytes THP-1 to endothelial cells, which is an important therapeutic approach to preventing atherogenesis. In conclusion, our study demonstrates that GPR173 agonism by Phoenixin-20 plays a protective role against ox-LDL-induced endothelial dysfunction, implying that Phoenixin-20 may have therapeutic implications in atherosclerosis.

ADAMTS proteases in cardiovascular physiology and disease.

The a disintegrin-like and metalloproteinase with thrombospondin motif (ADAMTS) family comprises 19 proteases that regulate the structure and function of extracellular proteins in the extracellular matrix and blood. The best characterized cardiovascular role is that of ADAMTS-13 in blood. Moderately low ADAMTS-13 levels increase the risk of ischeamic stroke and very low levels (less than 10%) can cause thrombotic thrombocytopenic purpura (TTP). Recombinant ADAMTS-13 is currently in clinical trials for treatment of TTP. Recently, new cardiovascular roles for ADAMTS proteases have been discovered. Several ADAMTS family members are important in the development of blood vessels and the heart, especially the valves. A number of studies have also investigated the potential role of ADAMTS-1, -4 and -5 in cardiovascular disease. They cleave proteoglycans such as versican, which represent major structural components of the arteries. ADAMTS-7 and -8 are attracting considerable interest owing to their implication in atherosclerosis and pulmonary arterial hypertension, respectively. Mutations in the ADAMTS19 gene cause progressive heart valve disease and missense variants in ADAMTS6 are associated with cardiac conduction. In this review, we discuss in detail the evidence for these and other cardiovascular roles of ADAMTS family members, their proteolytic substrates and the potential molecular mechanisms involved.

Abstract 16286: Absence of Fxyd1 is Associated With a Female-specific Pro-inflammatory and Hypercholesterolemic Environment: Implications for Atherosclerosis

Introduction: Bioavailability of nitric oxide (NO) is often compromised in early atherosclerosis, driving disease onset. This is usually due to dysfunctional endothelial nitric oxide synthase (eNOS). We have found that the transmembrane protein, FXYD1, is highly concentrated in the caveolae sub-cellular region and is closely associated with eNOS. Our preliminary data suggest that FXYD1 protects eNOS from redox-dependent inactivation. So, we hypothesise that FXYD1 may protect against atherosclerosis. Hypothesis: We aimed to test the role of FXYD1 in a murine model of atherosclerosis Methods: We produced a novel mutant mouse line by cross-breeding FXYD1 heterozygote (FXYD1 +/- ) and apolipoprotein E knock out (ApoE -/- ) mice. FXYD1 -/- /ApoE -/- and FXYD1 +/+ /ApoE -/- littermates were fed a high fat/high cholesterol diet from 6-8 weeks of age for 16 weeks. At sacrifice, blood was taken, and plasma was separated for analysis of cholesterol and pro-inflammatory cytokines using ELISA. The thoracic aorta was isolated and formalin-fixed to assess atherosclerotic plaque development using oil red O stain. Immunoblotting for eNOS expression was performed in heart lysates. Results: Plasma total cholesterol was significantly increased in FXYD1-/-/ApoE-/- female mice (n = 14 compared to FXYD1+/+/ApoE-/- mice (n = 21; p&lt;0.05)). Circulating IL-1β levels were also significantly increased in female FXYD1-/-/ApoE-/- vs. FXYD1+/+/ApoE-/- mice. Despite this, there was no effect on plaque size as determined by oil red O stain of fixed aortae. eNOS protein expression was decreased in heart tissue from FXYD1-/-/ApoE-/- vs. FXYD1+/+/ApoE-/- female mice which may lead to lower NO generation. All of the FXYD1-mediated changes were specific to female mice as we detected no differences in these parameters in littermate males. Conclusions: FXYD1-/- atherosclerotic female mice have higher circulating lipids and pro-inflammatory cytokines, but this does not appear to alter plaque development in the short term. Ongoing studies will determine the effect on plaque stability and role of FXYD1 in lipidomics. FXYD1 appears to have an anti-inflammatory role and may also be involved in cholesterol metabolism or handling. This could provide a novel therapeutic angle for females.