Human Coronary Endothelial Cells Research Articles

Atherosclerotic Plaque Epigenetic Age Acceleration Predicts a Poor Prognosis and Is Associated With Endothelial-to-Mesenchymal Transition in Humans.

Epigenetic age estimators (clocks) are predictive of human mortality risk. However, it is not yet known whether the epigenetic age of atherosclerotic plaques is predictive for the risk of cardiovascular events. Whole-genome DNA methylation of human carotid atherosclerotic plaques (n=485) and of blood (n=93) from the Athero-Express endarterectomy cohort was used to calculate epigenetic age acceleration (EAA). EAA was linked to clinical characteristics, plaque histology, and future cardiovascular events (n=136). We studied whole-genome DNA methylation and bulk and single-cell transcriptomics to uncover molecular mechanisms of plaque EAA. We experimentally confirmed our in silico findings using in vitro experiments in primary human coronary endothelial cells. Male and female patients with severe atherosclerosis had a median chronological age of 69 years. The median epigenetic age was 65 years in females (median EAA, -2.2 [interquartile range, -4.3 to 2.2] years) and 68 years in males (median EAA, -0.3 [interquartile range, -2.9 to 3.8] years). Patients with diabetes and a high body mass index had higher plaque EAA. Increased EAA of plaque predicted future events in a 3-year follow-up in a Cox regression model (univariate hazard ratio, 1.7; P=0.0034) and adjusted multivariate model (hazard ratio, 1.56; P=0.02). Plaque EAA predicted outcome independent of blood EAA (hazard ratio, 1.3; P=0.018) and of plaque hemorrhage (hazard ratio, 1.7; P=0.02). Single-cell RNA sequencing in plaque samples from 46 patients in the same cohort revealed smooth muscle and endothelial cells as important cell types in plaque EAA. Endothelial-to-mesenchymal transition was associated with EAA, which was experimentally confirmed by TGFβ-triggered endothelial-to-mesenchymal transition inducing rapid epigenetic aging in coronary endothelial cells. Plaque EAA is a strong and independent marker of poor outcome in patients with severe atherosclerosis. Plaque EAA was linked to mesenchymal endothelial and smooth muscle cells. Endothelial-to-mesenchymal transition was associated with EAA, which was experimentally validated. Epigenetic aging mechanisms may provide new targets for treatments that reduce atherosclerosis complications.

Nuciferine reduces vascular leakage and improves cardiac function in acute myocardial infarction by regulating the PI3K/AKT pathway

The destruction of the microvascular structure and function can seriously affect the survival and prognosis of patients with acute myocardial infarction (AMI). Nuciferine has a potentially beneficial effect in the treatment of cardiovascular disease, albeit its role in microvascular structure and function during AMI remains unclear. This study aimed to investigate the protective effect and the related mechanisms of nuciferine in microvascular injury during AMI. Cardiac functions and pathological examination were conducted in vivo to investigate the effect of nuciferine on AMI. The effect of nuciferine on permeability and adherens junctions in endothelial cells was evaluated in vitro, and the phosphorylation level of the PI3K/AKT pathway (in the presence or absence of PI3K inhibitors) was also analyzed. In vivo results indicated that nuciferine inhibited ischemia-induced cardiomyocyte damage and vascular leakage and improved cardiac function. In addition, the in vitro results revealed that nuciferine could effectively inhibit oxygen–glucose deprivation (OGD) stimulated breakdown of the structure and function of human coronary microvascular endothelial cells (HCMECs). Moreover, nuciferine could significantly increase the phosphorylation level of the PI3K/AKT pathway. Finally, the inhibitor wortmannin could reverse the protective effect of nuciferine on HCMECs. Nuciferine inhibited AMI-induced microvascular injury by regulating the PI3K/AKT pathway and protecting the endothelial barrier function in mice.

Involvement of IL-17 A/IL-17 Receptor A with Neutrophil Recruitment and the Severity of Coronary Arteritis in Kawasaki Disease

PurposeTo assess the role of the interleukin (IL)-17 A/IL-17 receptor A (IL-17RA) in Kawasaki disease (KD)-related coronary arteritis (CA).MethodsIn human study, the plasma levels of IL-17 A and coronary arteries were concurrently examined in acute KD patients. In vitro responses of human coronary endothelial cells to plasma stimulation were investigated with and without IL-17RA neutralization. A murine model of Lactobacillus casei cell-wall extract (LCWE)-induced CA using wild-type Balb/c and Il17ra-deficient mice were also inspected.ResultsThe plasma levels of IL-17 A were significantly higher in KD patients before intravenous immunoglobulin therapy, especially in those with coronary artery lesion. The pre-IVIG IL-17 A levels positively correlated with maximal z scores of coronary diameters and plasma-induced endothelial mRNA levels of chemokine (C-X-C motif) ligand-1, IL-8, and IL-17RA. IL-17RA blockade significantly reduced such endothelial upregulations of aforementioned three genes and inducible nitric oxide synthase, and neutrophil transmigration. IL-17RA expression was enhanced on peripheral blood mononuclear cells in pre-IVIG KD patients, and in the aortic rings and spleens of the LCWE-stimulated mice. LCWE-induced CA composed of dual-positive Ly6G- and IL-17 A-stained infiltrates. Il17ra-deficient mice showed reduced CA severity with the fewer number of neutrophils and lower early inducible nitric oxide synthase and chemokine (C-X-C motif) ligand-1 mRNA expressions than Il17ra+/+ littermates, and absent IL-17RA upregulation at aortic roots.ConclusionIL-17 A/IL-17RA axis may play a role in mediating aortic neutrophil chemoattraction, thus contributory to the severity of CA in both humans and mice. These findings may help to develop a new therapeutic strategy toward ameliorating KD-related CA.

Angiotensin-converting enzyme inhibitors provide a protective effect on hypoxia-induced injury in human coronary artery endothelial cells via Nrf2 signaling and PLVAP

BACKGROUND: Angiotensin-converting enzyme inhibitors (ACEIs) were reported to protect from hypoxia-induced oxidative stress in coronary endothelial cells (CECs) after acute myocardial infarction (AMI). Nrf2 shows a protective effect in hypoxia-induced CECs after AMI. Plasmalemma vesicle-associated protein (PLVAP) plays a pivotal role in angiogenesis after AMI. AIM: To explore the protective effect of ACEIs and the involved mechanisms under hypoxia challenge. METHODS: Human coronary endothelial cells (HCAECs) were used to establish hypoxia-induced oxidative stress injury in vitro. Flow cytometry was used to evaluate the protective effect of ACEI on hypoxia conditions.ET-1, NO, ROS, and VEGF were detected by ELISA. HO-1, Nrf2, and Keap-1, the pivotal member in the Nrf2 signaling pathway, eNOS and PLVAP were detected in HEAECs treated with ACEI by immunofluorescence, qPCR, and western blotting. RESULTS: The hypoxia ACEI or Nrf2 agonist groups showed higher cell viability compared with the hypoxia control group at 24 (61.75±1.16 or 61.23±0.59 vs. 44.24±0.58, both P < 0.05) and 48 h (41.85±1.19 or 59.64±1.13 vs. 22.98±0.25, both P < 0.05). ACEI decreased the levels of ET-1 and ROS under hypoxia challenge at 24 and 48 h (all P < 0.05); ACEI increased the VEGF and NO levels (all P < 0.05). ACEI promoted the expression level of eNOS, HO-1, Nrf2 and PLVAP but inhibited Keap-1 expression at the mRNA and protein levels (all P < 0.05). Blockade of the Nrf2 signaling pathway significantly decreased the expression level of PLVAP. CONCLUSION: ACEI protects hypoxia-treated HEAECs by activating the Nrf2 signaling pathway and upregulating the expression of PLVAP.

MiRNA-100 ameliorates diabetes mellitus-induced erectile dysfunction by modulating autophagy, anti-inflammatory, and antifibrotic effects.

Diabetes mellitus-induced erectile dysfunction (DMED) has become a common disease in adult men that can seriously reduce the quality of life of patients, and new therapies are urgently needed. miRNA-100 has many targets and can induce autophagy and reduce fibrosis by inhibiting the mTOR pathway and the TGF-β pathway. However, no research has been conducted with miR-100 in the field of DMED, and the specific mechanism of action is still unclear. To ascertain the effects of miR-100 on corpus cavernosum tissue of DMED rats and vascular endothelial cells in a high glucose environment and to elucidate the relevant mechanisms in autophagy, fibrosis and inflammation to find a new approach for the DMED therapy. Thirty rats were divided into three groups: the control group, the DMED group, and the DMED + miR-100 group. Using intraperitoneal injections of streptozotocin, all rats except the control group were modeled with diabetes mellitus, which was verified using the apomorphine (APO) test. For rats in the DMED + miR-100 group, rno-miR-100-5p agomir (50nmol/kg, every 2 days, 6 times in total) was injected via the tail vein. After 13weeks, the erectile function of each rat was assessed using cavernous manometry, and the corpus cavernosum tissue was harvested for subsequent experiments. For cellular experiments, human coronary microartery endothelial cells (HCMEC) were divided into four groups: the control group, the high-glucose (HG, 40mM) group, the HG + mimic group, and the HG + inhibitor group. The cells were cultured for 6 days and collected for subsequent experiments 2 days after transfection. Diabetic modeling impaired the erectile function in rats, and miR-100 reversed this effect. By measuring autophagy-related proteins such as mTOR/Raptor/Beclin1/p62/LC3B, we found that miR-100 could suppress the expression of mTOR and induce autophagy. The analysis of the eNOS/NO/cGMP axis function indicated that impaired endothelial function was improved by miR-100. By evaluating the TGF-β1/CTGF/Smad2/3 and NF-κB/TNF-α pathways, we found that miR-100 could lower the level of inflammation and fibrosis, which contributed to the improvement of the erectile function. Cellular experiments can be used as supporting evidence for these findings. MiR-100 can improve the erectile function by inhibiting mTOR and thus inducing autophagy, improving the endothelial function through the eNOS/NO/cGMP axis, and exerting antifibrotic and anti-inflammatory effects, which may provide new ideas and directions for the treatment of DMED.

MiR-125b-5p alleviates the damage of myocardial infarction by inhibiting the NFAT2 to reduce F2RL2 expression.

Aim: To explore the effect of miR-125b-5p/nuclear factor of activated T cells 1 (NFAT2)/F2RL2 on myocardial infarction (MI). Method: After establishment of MI mouse model and oxygen glucose deprivation (OGD)-induced cell model, the effects of NFAT2 on the process of MI were observed, the effects of miR-125b-5p/NFAT2/F2RL2 on the cell viability, apoptosis, and inflammatory factors levels were determined. Result: NFAT2 silencing relieved MI and inhibited the inflammation in MI model mice. In OGD-induced human coronary artery endothelial cellsand human cardiac microvascular endothelial cells, miR-125b-5p enhanced cell viability, yet repressed cell apoptosis and inflammatory factors and NFAT2 levels. NFAT2 overexpression reversed the effects of miR-125b-5p, while F2RL2 silencing offset the effects of NFAT2 overexpression. Conclusion: MiR-125b-5p alleviates MI injury by inhibiting NFAT2 level to reduce F2RL2 expression.

Mechanisms by which statins protect endothelial cells from radiation-induced injury in the carotid artery.

The incidental use of statins during radiation therapy has been associated with a reduced long-term risk of developing atherosclerotic cardiovascular disease. However, the mechanisms by which statins protect the vasculature from irradiation injury remain poorly understood. Identify the mechanisms by which the hydrophilic and lipophilic statins pravastatin and atorvastatin preserve endothelial function after irradiation. Cultured human coronary and umbilical vein endothelial cells irradiated with 4 Gy and mice subjected to 12 Gy head-and-neck irradiation were pretreated with statins and tested for endothelial dysfunction, nitric oxide production, oxidative stress, and various mitochondrial phenotypes at 24 and 240 h after irradiation. Both pravastatin (hydrophilic) and atorvastatin (lipophilic) were sufficient to prevent the loss of endothelium-dependent relaxation of arteries after head-and-neck irradiation, preserve the production of nitric oxide by endothelial cells, and suppress the cytosolic reactive oxidative stress associated with irradiation. However, only pravastatin inhibited irradiation-induced production of mitochondrial superoxide; damage to the mitochondrial DNA; loss of electron transport chain activity; and expression of inflammatory markers. Our findings reveal some mechanistic underpinnings of the vasoprotective effects of statins after irradiation. Whereas both pravastatin and atorvastatin can shield from endothelial dysfunction after irradiation, pravastatin additionally suppresses mitochondrial injury and inflammatory responses involving mitochondria. Clinical follow-up studies will be necessary to determine whether hydrophilic statins are more effective than their lipophilic counterparts in reducing the risk of cardiovascular disease in patients undergoing radiation therapy.

Agext and Its Active Compounds as Potential Therapeutic Prevention against Atherosclerosis and Cardiovascular Disease

Advanced Glycation End-Products (AGEs) have been implicated in the chronic complications of Diabetes Mellitus (DM) and play an important role in the pathogenesis of atherosclerosis in human arteries. The main active compounds found in Aged Garlic Extract (AGExt) are S-Allyl Cysteine (SAC), N-Acetylcysteine (NAC) and S-allyl Mercaptocysteine (SAMC) and have powerful protective effects against oxidative stress and inhibit cellular damage by AGEs. Aims: To explore the effect of AGExt on the development of atherosclerosis also investigated the endothelial protective effects of AGExt, using Human Coronary Artery-Derived Endothelial Cells (HCAEC). The use of an optimised mixture of the above compounds required to obtain and provide maximal beneficial effects against oxidative stress, cell apoptosis and protein glycation. Results: AGExt has protective effects against the cellular damage of HCAEC. In addition, the in vivo study accessed the activity of SAC and NAC to reduce the severity of atherosclerosis formation in Apolipoprotein (ApoE-/-) DM model mouse. The compounds of AGExt in vitro had strong protective actions against the AGEs induced damage to ECs even at low concentrations (100 ng/ml). Such low concentrations may have therapeutic usefulness in patients with diabetes.

Selective NLRP3 Inflammasome Inhibitor MCC950 Suppresses Inflammation and Facilitates Healing in Vascular Materials.

Minimally invasive interventions using drug-eluting stents or balloons are a first-line treatment for certain occlusive cardiovascular diseases, but the major long-term cause of failure is neointimal hyperplasia (NIH). The drugs eluted from these devices are non-specific anti-proliferative drugs, such as paclitaxel (PTX) or sirolimus (SMS), which do not address the underlying inflammation. MCC950 is a selective inhibitor of the NLRP3-inflammasome, which drives sterile inflammation commonly observed in NIH. Additionally, in contrast to broad-spectrum anti-inflammatory drugs, MCC950 does not compromise global immune function due this selective activity. In this study, MCC950 is found to not impact the viability, integrity, or function of human coronary endothelial cells, in contrast to the non-specific anti-proliferative effects of PTX and SMS. Using an in vitro model of NLRP3-mediated inflammation in murine macrophages, MCC950 reduced IL-1β expression, which is a key driver of NIH. In an in vivo mouse model of NIH in vascular grafts, MCC950 significantly enhanced re-endothelialization and reduced NIH compared to PTX or SMS. These findings show the effectiveness of a targeted anti-inflammatory drug-elution strategy with significant implications for cardiovascular device intervention.

Donepezil prevents high glucose-induced endothelial barrier dysfunction and accelerates wound healing process in human coronary endothelial cells

Abstract The Cholinergic Anti-inflammatory Pathway (CAP) is a neurophysiological mechanism that regulates the immune system. Studies show that the CAP inhibits inflammation by suppressing cytokine synthesis via release of acetylcholine in the heart, lungs and gastrointestinal tract. Upon release, acetylcholine interacts with α7 nicotinic acetylcholine receptors (α7nAChR), down-regulate pro-inflammatory cytokine synthesis and prevent tissue damage and inflammation. Donepezil, a centrally acting reversible acetylcholinesterase inhibitor, has been used in the palliative treatment of Alzheimer’s disease (AD). We hypothesized that the donepezil prevents high glucose-induced endothelial barrier dysfunction and accelerates wound healing process in human coronary endothelial cells by preventing the destabilization of junctional proteins. We investigated the potential protective role of Donepezil in high glucose induced increase in human coronary artery endothelial (HCAE) permeability and wound healing process. Endothelial permeability was evaluated by using state of the art Electric Cell-substrate Impedance Sensing (ECIS) mechanism, a measure of trans-endothelial electrical resistance (TEER) across the endothelial monolayers using TEER electrodes. Wound healing assay was performed by employing electric signals to both wound and monitor the healing process in endothelial monolayer. Our data show that 25mM glucose concentration increased endothelial permeability and abrogated the wound healing process. Donepezil at the dose of 5 μM and 10 μM significantly prevented alteration of endothelial barrier function and enhances wound healing process in the presence of high glucose concentration.

Redox and metal profiles in human coronary endothelial and smooth muscle cells under hyperoxia, physiological normoxia and hypoxia: Effects of NRF2 signaling on intracellular zinc

Zinc is an important component of cellular antioxidant defenses and dysregulation of zinc homeostasis is a risk factor for coronary heart disease and ischemia/reperfusion injury. Intracellular homeostasis of metals, such as zinc, iron and calcium are interrelated with cellular responses to oxidative stress. Most cells experience significantly lower oxygen levels in vivo (2–10 kPa O2) compared to standard in vitro cell culture (18kPa O2). We report the first evidence that total intracellular zinc content decreases significantly in human coronary artery endothelial cells (HCAEC), but not in human coronary artery smooth muscle cells (HCASMC), after lowering of O2 levels from hyperoxia (18 kPa O2) to physiological normoxia (5 kPa O2) and hypoxia (1 kPa O2). This was paralleled by O2-dependent differences in redox phenotype based on measurements of glutathione, ATP and NRF2-targeted protein expression in HCAEC and HCASMC. NRF2-induced NQO1 expression was attenuated in both HCAEC and HCASMC under 5 kPa O2 compared to 18 kPa O2. Expression of the zinc efflux transporter ZnT1 increased in HCAEC under 5 kPa O2, whilst expression of the zinc-binding protein metallothionine (MT) decreased as O2 levels were lowered from 18 to 1 kPa O2. Negligible changes in ZnT1 and MT expression were observed in HCASMC. Silencing NRF2 transcription reduced total intracellular zinc under 18 kPa O2 in HCAEC with negligible changes in HCASMC, whilst NRF2 activation or overexpression increased zinc content in HCAEC, but not HCASMC, under 5 kPa O2. This study has identified cell type specific changes in the redox phenotype and metal profile in human coronary artery cells under physiological O2 levels. Our findings provide novel insights into the effect of NRF2 signaling on Zn content and may inform targeted therapies for cardiovascular diseases.

NR3C2 mediates oxidised low-density lipoprotein-induced human coronary endothelial cells dysfunction via modulation of NLRP3 inflammasome activation

Nuclear receptor subfamily 3 group C member 2 (NR3C2) has been revealed to affect the progression of multiple inflammatory diseases, while NR3C2’s efficacy in coronary artery disease (CAD) remains largely unsolved. The study intended to elucidate the possible mechanisms of NR3C2 in oxidised low density lipoprotein (ox-LDL)-induced inflammation in human coronary endothelial cells (HCAECs) via regulating NACHT, LRR, and PYD domains-containing protein 3 (NLRP3). Patients who underwent CT angiography or coronary angiography for suspected CAD in our hospital were collected. The patients were divided into the CAD and the non-CAD (NCAD) groups. The expression of NR3C2 and NLRP3 in the peripheral blood of patients in both groups was examined by RT-qPCR. HCAECs were treated with ox-LDL to establish the model. The expression of NR3C2 and NLRP3 in ox-LDL-induced HCAECs was tested by RT-qPCR. The proliferation of HCAECs was measured using CCK-8 assay, the apoptosis of HCAECs was assessed by flow cytometry, and the levels of inflammation-related factors IL-1β and IL-18 in the cell supernatant were evaluated by ELISA. The molecular mechanisms of these factors in the proliferation and apoptosis of HCAECs and in the inflammatory response were further determined by knockdown and overexpression systems. The relationship between NR3C2 and NLRP3 was determined by ChIP and luciferase activity assays and bioinformatics analysis. NR3C2 and NLRP3 levels were elevated in the serum of CAD patients. The ox-LDL treatment elevated NR3C2 levels, evoked apoptosis and inflammation, and impeded cell viability in HCAECs, whereas downregulation of NR3C2 increased cell viability and reduced apoptosis and inflammatory response in ox-LDL-induced inflammation in HCAECs. NR3C2 levels were positively correlated with NLRP3, and NR3C2 elevated NLRP3 expression through transcription. Overexpression of NLRP3 counteracted the impacts of silencing NR3C2 on cell viability, cell apoptosis, and inflammatory response in ox-LDL-induced HCAECs. Our research stresses that NR3C2 transcription promotes NLRP3 to induce inflammatory responses in ox-LDL-induced HCAECs.

The Effects of Sirolimus and Magnesium on Primary Human Coronary Endothelial Cells: An In Vitro Study.

Drug eluting magnesium (Mg) bioresorbable scaffolds represent a novel paradigm in percutaneous coronary intervention because Mg-based alloys are biocompatible, have adequate mechanical properties and can be resorbed without adverse events. Importantly, Mg is fundamental in many biological processes, mitigates the inflammatory response and is beneficial for the endothelium. Sirolimus is widely used as an antiproliferative agent in drug eluting stents to inhibit the proliferation of smooth muscle cells, thus reducing the occurrence of stent restenosis. Little is known about the potential interplay between sirolimus and Mg in cultured human coronary artery endothelial cells (hCAEC). Therefore, the cells were treated with sirolimus in the presence of different concentrations of extracellular Mg. Cell viability, migration, barrier function, adhesivity and nitric oxide synthesis were assessed. Sirolimus impairs the viability of subconfluent, but not of confluent cells independently from the concentration of Mg in the culture medium. In confluent cells, sirolimus inhibits migration, while it cooperates with Mg in exerting an anti-inflammatory action that might have a role in preventing restenosis and thrombosis.

The role of FOXO4/NFAT2 signaling pathway in dysfunction of human coronary endothelial cells and inflammatory infiltration of vasculitis in Kawasaki disease.

The Ca+/NFAT (Nuclear factor of activated T cells) signaling pathway activation is implicated in the pathogenesis of Kawasaki disease (KD); however, we lack detailed information regarding the regulatory network involved in the human coronary endothelial cell dysfunction and cardiovascular lesion development. Herein, we aimed to use mouse and endothelial cell models of KD vasculitis in vivo and in vitro to characterize the regulatory network of NFAT pathway in KD. Among the NFAT gene family, NFAT2 showed the strongest transcriptional activity in peripheral blood mononuclear cells (PBMCs) from patients with KD. Then, NFAT2 overexpression and knockdown experiments in Human coronary artery endothelial cells (HCAECs) indicated that NFAT2 overexpression disrupted endothelial cell homeostasis by regulation of adherens junctions, whereas its knockdown protected HCAECs from such dysfunction. Combined analysis using RNA-sequencing and transcription factor (TF) binding site analysis in the NFAT2 promoter region predicted regulation by Forkhead box O4 (FOXO4). Western blotting, chromatin immunoprecipitation, and luciferase assays validated that FOXO4 binds to the promoter and transcriptionally represses NFAT2. Moreover, Foxo4 knockout increased the extent of inflamed vascular tissues in a mouse model of KD vasculitis. Functional experiments showed that inhibition NFAT2 relieved Foxo4 knockout exaggerated vasculitis in vivo. Our findings revealed the FOXO4/NFAT2 axis as a vital pathway in the progression of KD that is associated with endothelial cell homeostasis and cardiovascular inflammation development.

Normoxic HIF-1α Stabilization Caused by Local Inflammatory Factors and Its Consequences in Human Coronary Artery Endothelial Cells.

Knowledge about normoxic hypoxia-inducible factor (HIF)-1α stabilization is limited. We investigated normoxic HIF-1α stabilization and its consequences using live cell imaging, immunoblotting, Bio-Plex multiplex immunoassay, immunofluorescence staining, and barrier integrity assays. We demonstrate for the first time that IL-8 and M-CSF caused HIF-1α stabilization and translocation into the nucleus under normoxic conditions in both human coronary endothelial cells (HCAECs) and HIF-1α-mKate2-expressing HEK-293 cells. In line with the current literature, our data show significant normoxic HIF-1α stabilization caused by TNF-α, INF-γ, IL-1β, and IGF-I in both cell lines, as well. Treatment with a cocktail consisting of TNF-α, INF-γ, and IL-1β caused significantly stronger HIF-1α stabilization in comparison to single treatments. Interestingly, this cumulative effect was not observed during simultaneous treatment with IL-8, M-CSF, and IGF-I. Furthermore, we identified two different kinetics of HIF-1α stabilization under normoxic conditions. Our data demonstrate elevated protein levels of HIF-1α-related genes known to be involved in the development of atherosclerosis. Moreover, we demonstrate an endothelial barrier dysfunction in HCAECs upon our treatments and during normoxic HIF-1α stabilization comparable to that under hypoxia. This study expands the knowledge of normoxic HIF-1α stabilization and activation and its consequences on the endothelial secretome and barrier function. Our data imply an active role of HIF-1α in vivo in the vasculature in the absence of hypoxia.

Abstract 13094: Extracellular Vesicles Associate With Cardio-Metabolic Status and Endothelial Dysfunction in a Cohort of African-American Women

Extracellular vesicles (EVs) are emerging as promising biomarkers for cardiovascular disease (CVD) and contributors to CVD pathogenesis. Plasma EVs access the endothelium from various vascular beds allowing them to impact endothelial function and inform on the global particulate secretome produced by parenchymal, vascular and immune cells. In this study we examined associations between plasma EVs and biochemical and physiological parameters in a cohort of African American (AA) women at risk for CVD. We also examined EV effect on coronary endothelial function. This study will serve as baseline data for a longitudinal study aimed to determine the effects of exercise on EVs and endothelial function in a similar cohort.A cohort of 24 AA women between 22-71 yrs, with BMI between 26-47 kg/m 2 and ASCVD risk scores between 2.3-22.1 were included in the study. EVs were isolated from fasted heparinized plasma using size exclusion chromatography. EV size and numbers were determined using nanoparticle tracking analysis. Lipids, inflammatory cytokines, and metabolic panels were measured at the time of blood draw. Human coronary endothelial cells were treated with EVs from participants and endothelial barrier function and migration were measured using ECIS technology. Associations were determined using multivariable linear regression analysis, adjusted for BMI and ASCVD risk.We found a negative association (beta=-0.712, p<0.01) between total triglycerides (TG), TG rich lipoprotein (Lp), and EV size; EV concentration was positively associated (beta= 0.51-0.61, p<0.01) with TG rich Lp, LDL cholesterol and TNFa. Reduced endothelial barrier function due to EVs was positively associated with monocyte counts (beta=0.42, p<0.05). EVs effect on increased endothelial migration was strongly and negatively associated with monocyte counts (beta=-0.85, p<0.001), IL8 and CXCl10 (beta=-0.56-0.46, p<0.05).Collectively these data show that EVs number and size strongly associate with circulating lipids, while EV impact on endothelial dysfunction is associated with inflammatory markers. EVs are therefore promising indicators of endothelial dysfunction that associate with inflammatory and metabolic markers even after adjusting for BMI and ASCVD risk.

Abstract 14966: Mechanisms of Protection From Radiation-Induced Endothelial Injury by Statins

Introduction: The incidental use of statins during radiation therapy has been associated with a decreased risk of long-term atherosclerotic cardiovascular (CV) disease. However, the mechanisms by which statins protect the vasculature from irradiation injury remain poorly understood. Hypothesis: Establish the mechanisms by which lipophilic and hydrophilic statins preserve endothelial function after irradiation. Methods: Cultured human coronary and umbilical vein endothelial cells irradiated with 4 Gy and mice on day 1 and 10 after head and neck irradiation with 12 Gy were assessed for endothelial dysfunction, nitric oxide and reactive oxidative stress production and various mitochondrial phenotypes. Results: Pretreatment of mice with pravastatin or atorvastatin prevented the loss of endothelium-dependent relaxation on day 1 and 10 after head and neck irradiation. Both statins inhibit the loss of nitric oxide, and the increase in cytosolic reactive oxidative stress in endothelial cells. However, only pravastatin blocked mitochondrial superoxide production, mitochondrial DNA damage and loss of electron complex activity. In contrast to atorvastatin, pravastatin also significantly reduced the expression of inflammatory markers TNF-α, NFκB p65 and p50 after irradiation. Conclusions: Our findings provide mechanistic underpinnings for the vasoprotective effects of statins after irradiation. While lipo- and hydrophilic statins shield from endothelial dysfunction after irradiation, pravastatin also prevents mitochondrial injury and decreases an inflammatory response by actions in mitochondria. A correlation with clinical studies is necessary to determine whether hydrophilic statins, such as pravastatin reduce the risk of CV disease after irradiation in humans to a greater extent than lipophilic statins.

Abstract 15392: Radiation-Induced Coronary Microvascular Leakage is Mediated by Loss of Endothelial Tight Junction Protein Claudin-1

Background: Ionizing radiation (IR) exposure to the heart during cancer therapy induces coronary microvascular leakage. Increased microvascular porosity allows inflammatory cell extravasation into the perivascular and myocardial interstitial space leading to fibrotic end organ damage. Hypothesis: Radiation-induced coronary microvascular leakage is mediated by a loss of a constitutively expressed tight-junction protein, claudin-1 (cldn1). Methods: We studied the function of cldn1 in human coronary vascular endothelial cells (HMVECs) and in mice using oligonucleotide-based cldn1 gene deletion. For the gain of function, we developed vascular-specific (VE-cadherin promotor-linked) claudin-1 overexpressing transgenic (TG) mice. We studied the effect of IR in cldn1 loss and gain of function models. Capillary permeability was assessed by FITC-dextran permeability and Evans blue dye injection, in vitro and in vivo, respectively . The extent of end-organ damage was examined by analyzing myocardial and perivascular fibrosis. Results: In HMVECs, cldn1 gene silencing (control, 1.0±0.34; siRNA, 0.026±0.03; p<0.001) led to increased permeability (control, 1.0±0.01, siRNA, 1.3±0.01; p<001). In mice, genetically engineered anti-cldn1 siRNA administration knocked down myocardial cldn1 expression (control, 1.0±0.18; siRNA, 0.51±0.11; p=0.04). Functionally, cldn1 knockdown led to increased microvascular extravasation (control, 1.0±0.23, cldn1-siRNA 0.38±0.27 p=0.002). Cardiac morphometry in these mice showed myocardial fibrosis (control, 1.0±0.19; siRNA, 1.29±0.35; p=0.048). Cardiac irradiation significantly decreased myocardial cldn1 (control 1.0±0.27, IR 0.45±0.31; p=0.001) and dye leakage (control 1.0±0.18, IR 1.28±0.22; p=0.007). Conversely, endothelium-targeted cldn1 overexpression in mice prevented abnormal microvasculature permeability (WT 1.0±0.23, TG 0.38±0.27 p=0.002) and conferred protection from IR-induced fibroinflammatory changes. Conclusions: Our study shows that cldn1 is crucial for maintaining coronary microvascular permeability. Prevention of cldn1 degradation or cldn1 reconstitution using novel pharmacotherapeutic approaches can prevent cardiac end-organ damage induced by cardiac IR.

Multi-species meta-analysis identifies transcriptional signatures associated with cardiac endothelial responses in the ischaemic heart.

Myocardial infarction remains the leading cause of heart failure. The adult human heart lacks the capacity to undergo endogenous regeneration. New blood vessel growth is integral to regenerative medicine necessitating a comprehensive understanding of the pathways that regulate vascular regeneration. We sought to define the transcriptomic dynamics of coronary endothelial cells following ischaemic injuries in the developing and adult mouse and human heart and to identify new mechanistic insights and targets for cardiovascular regeneration. We carried out a comprehensive meta-analysis of integrated single cell RNA-sequencing data of coronary vascular endothelial cells from the developing and adult mouse and human heart spanning healthy and acute and chronic ischaemic cardiac disease. We identified species-conserved gene regulatory pathways aligned to endogenous neovascularisation. We annotated injury-associated temporal shifts of the endothelial transcriptome and validated four genes: VEGF-C, KLF4, EGR1 and ZFP36. Moreover, we showed that ZFP36 regulates human coronary endothelial cell proliferation and defined that VEGF-C administration in vivo enhances clonal expansion of the cardiac vasculature post-myocardial infarction. Finally, we constructed a coronary endothelial cell meta-atlas, CrescENDO, to empower future in-depth research to target pathways associated with coronary neovascularisation. We present a high-resolution single cell meta-atlas of healthy and injured coronary endothelial cells in the mouse and human heart, revealing a suite of novel targets with great potential to promote vascular regeneration, and providing a rich resource for therapeutic development. Myocardial infarction is the leading cause of heart failure, a condition with high morbidity and mortality. Vascular regeneration is vital to tissue survival and functional restoration while a comprehensive understanding of the underpinning mechanisms is lacking. We show that the meta-analysis of single cell RNA-sequencing data excels at deciphering multi-faceted vascular responses conserved between mouse and human following ischaemic injury. We envision that these data will inform future strategies and accelerate therapeutic development for promoting vascular regeneration in the ischaemic heart.

Pigment epithelium-derived factor maintains tight junction stability after myocardial infarction in rats through inhibition of the Wnt/β-catenin signaling pathway

PurposeThe impairment of the coronary microcirculatory barrier caused by acute myocardial infarction (AMI) is closely related to poor prognosis. Recently, pigment epithelial-derived factor (PEDF) has been proven to be a promising cardiovascular protective drug. In this study, we demonstrated the protective role of PEDF in endothelial tight junctions (TJs) and the vascular barrier in AMI. Materials and methods2, 3, 5-triphenyltetrazolium chloride (TTC), echocardiography and immunofluorescence staining were used to observe the size of infarcted myocardium area and cardiac function in myocardial tissue, and the distribution of TJ proteins in human coronary endothelial cells (HCAEC). Dextran leakage assay and Transwell were used to assess the extent of vascular and HCAEC leakage. Polymerase chain reaction (PCR) and Western blot were used to detect TJ-related mRNA and protein, and signaling pathway protein expression. ResultsPEDF effectively reduced the infarction area and improved cardiac function in AMI rats, and lowered the leakage in AMI rats’ angiocarpy and oxygen-glucose deprivation (OGD)–treated HCAEC. Furthermore, PEDF upregulated the expression of TJ mRNA and proteins in vivo and vitro. Mechanistically, PEDF inhibited the expression of phosphorylated low-density lipoprotein receptor-related protein 6 (p-LRP6) and active β-catenin under OGD, thus suppressing the activation of the classical Wnt pathway. ConclusionsThese novel findings demonstrated that PEDF maintained the expression of TJ proteins and endothelial barrier integrity by inhibiting the classical Wnt pathway during AMI.