Lingyun Zu

High-density lipoprotein nitration and chlorination catalyzed by myeloperoxidase impair its effect of promoting endothelial repair

High-density lipoprotein (HDL) plays a key role in protecting against atherosclerosis. In cardiovascular disease, HDL can be nitrated and chlorinated by myeloperoxidase (MPO). In this study, we discovered that MPO-oxidized HDL is dysfunctional in promoting endothelial repair compared to normal HDL. Proliferation assay, wound healing, and transwell migration experiments showed that MPO-oxidized HDL was associated with a reduced stimulation of endothelial cell (EC) proliferation and migration. In addition, we found that Akt and ERK1/2 phosphorylation in ECs was significantly lower when ECs were incubated with oxidized HDL compared with normal HDL. To further determine whether oxidized HDL diminished EC migration through the PI3K/Akt and MEK/ERK pathways, we performed experiments with inhibitors of both these pathways. The transwell experiments performed in the presence of these inhibitors showed that the migration capacity was reduced and the differences observed between normal HDL and oxidized HDL were diminished. Furthermore, to study the effects of oxidized HDL on endothelial cells in vivo, we performed a carotid artery electric injury model on nude mice injected with either normal or oxidized HDL. Oxidized HDL inhibited reendothelialization compared to normal HDL in vivo. These findings implicate a key role for MPO-oxidized HDL in the pathogenesis of cardiovascular disease.

Platelet‐Derived Microparticles are Implicated in Remote Ischemia Conditioning in a Rat Model of Cerebral Infarction

Remote ischemic preconditioning protects against ischemic organ damage by giving short periods of subcritical ischemia to a remote organ. We tested the hypothesis that remote ischemic conditioning can attenuate cerebral stroke in a rat middle cerebral artery occlusion (MCAO) model by microparticles (MPs).

Macrophage Foam Cell–Derived Extracellular Vesicles Promote Vascular Smooth Muscle Cell Migration and Adhesion

Background A new mechanism for intercellular communication has recently emerged that involves intercellular transfer of extracellular vesicles (EVs). Several studies have indicated that EVs may play a potential role in cell‐to‐cell communication between macrophage foam cells and vascular smooth muscle cells (VSMCs) in atherosclerotic lesion. Methods and Results This study involved the comparison of circulating EVs from atherosclerotic patients and control participants. The results showed that the circulation of the patients contained more leukocyte‐derived EVs and that these EVs promoted more VSMC adhesion and migration than those of healthy participants. We then established a macrophage foam cell model and characterized the EVs from the macrophages. We used flow cytometric analyses and cell migration and adhesion assays and determined that the foam cells generated more EVs than the normal macrophages and that the foam cell–derived EVs were capable of promoting increased levels of VSMC migration and adhesion. Furthermore, we performed a proteomic analysis of the EVs. The data showed that the foam cell–derived EVs may promote VSMC adhesion and migration by regulating the actin cytoskeleton and focal adhesion pathways. In addition, Western blotting revealed that foam cell–derived EVs could promote the phosphorylation of ERK and Akt in VSMCs in a time‐dependent manner. We also found that foam cell–derived EVs could enter the VSMCs and transfer integrins to the surface of these cells. Conclusions The data in our present study provide the first evidence that EVs from foam cells could promote VSMC migration and adhesion, which may be mediated by the integration of EVs into VSMCs and the subsequent downstream activation of ERK and Akt.

Endothelial microparticles after antihypertensive and lipid-lowering therapy inhibit the adhesion of monocytes to endothelial cells☆

☆ This project was supported by National Natural Scie 81300076, 81370235, 81170101); the Beijing Natural Scie Hisun-Pfizer Inc. researchers sponsored funds (number: WS ⁎ Corresponding authors. E-mail addresses: guo_li_jun@sohu.com (L. Guo), zhen 1 Lingyun Zu and Chuan Ren have contributed equally t 2 These authors take responsibility for all aspects of the r of the data presented and their discussed interpretation.

Oxidized low-density lipoprotein-induced microparticles promote endothelial monocyte adhesion via intercellular adhesion molecule 1

Oxidized low-density lipoprotein (oxLDL) accumulates early in atherosclerotic lesions and plays an important role in the progressive formation of atherosclerotic plaques. Endothelial derived microparticles (EMPs) form a heterogeneous population of <1-μm particles that shed from endothelial membranes upon activation. While EMPs are shown to be involved in atherosclerotic pathophysiology and progression, there is no report regarding the relationship between oxLDL and EMPs. In this study, we aim to determine the influence of oxLDL on endothelial microparticle release and the subsequent regulation of the endothelial activation. EMPs were collected from the medium of human umbilical vein endothelial cells (HUVECs) treated with oxLDL or PBS as control. We find that oxLDL increases the release of EMPs containing intercellular adhesion molecule 1 (ICAM-1) but not vascular cell adhesion molecule 1 (VCAM-1). Confocal microscopy analysis further demonstrates that these EMPs interact with endothelial cells and increase the expression of ICAM-1 in HUVECs. The fact that injecting oxLDL-induced EMPs via the tail vein of ICR mice augments ICAM-1 expression on aortic endothelial cells confirms our results in vivo. Finally, oxLDL-induced EMPs from HUVECs increase the adhesion of monocytes to endothelial cells as determined by the adhesion assay. Our study suggests that oxLDL may augment the release of EMPs harboring increased levels of ICAM-1 that can be transferred to endothelial cells elsewhere. This leads to increased monocyte recruitment in other regions where oxLDL accumulation was initially more limited. EMPs may therefore serve as the mediator that propagates oxLDL-induced endothelial inflammation.

Proteomic research of high-glucose-activated endothelial microparticles and related proteins to Alzheimer’s disease

The study was designed to discover the biological function of endotheliocyte-derived microparticles in diabetes condition. A quantitative shotgun proteomics methodology was performed to study the proteome of these high-glucose-activated endothelial microparticles. A total of 1428 proteins were identified, containing 1421 and 1423 proteins in control and high-glucose groups, respectively. According to the ExoCarta database, 669 proteins have previously been identified in microparticles. The proteins associated with disease were identified in this study, and notably, 30 proteins have been reported to be associated with Alzheimer’s disease, including amyloid beta A4 protein. Besides, the peptide abundance of amyloid beta A4 protein from control group was much less than that from high-glucose group. In conclusion, this work revealed the proteome of endothelial microparticles in mimic diabetes condition and provided a new proteomic evidence for Alzheimer’s disease to be counted as the type 3 diabetes.

An analysis of patients receiving emergency CAG without PCI and the value of GRACE score in predicting PCI possibilities in NSTE-ACS patients.

Background There are patients who underwent emergency coronary angiography (CAG) but did not receive percutaneous coronary intervention (PCI). The aim of this study was to analyze these reasons. Methods This is a single-center retrospective study. We recruited 201 consecutive patients who received emergency CAG but did not receive PCI. To investigate the value of the Global Registry of Acute Coronary Events (GRACE) score in predicting PCI possibilities in non-ST segment elevation acute coronary syndrome (NSTE-ACS) patients, we recruited 80 consecutive patients who presented with NSTE-ACS and received emergency CAG as well as emergency PCI. Results Among the 201 patients who received emergency CAG but did not receive PCI, 26% patients had final diagnosis other than coronary heart disease. In the patients with significant coronary artery stenosis, 23 patients (11.5%) were recommended to coronary artery bypass grafting (CABG), one patient (0.5%) refused PCI; 13 patients (6.5%) with significant thrombus burden were treated with glycoprotein IIb/IIIa receptor antagonist; 74 patients (36.8%) were treated with drug therapy because no severe stenosis (> 70%) was present in the crime vessel. Moreover, 80 of the 201 patients were presented with NSTE-ACS (excluding those patients with final diagnosis other than coronary heart disease, excluding those patients planned for CABG treatment), referred as non PCI NSTE-ACS. When comparing their GRACE scores with 80 consecutive patients presented with NSTE-ACS who received emergency CAG as well as emergency PCI (referred as PCI NSTE-ACS), we found that PCI NSTE-ACS patients had significantly higher GRACE scores compared with non PCI NSTE-ACS patients. We then used Receiver Operator Characteristic Curve (ROC) to test whether the GRACE score is good at evaluating the possibilities of PCI in NSTE-ACS patients. The area under the curve was 0.854 ± 0.030 (P < 0.001), indicating good predictive value. Furthermore, we analyzed results derived from ROC statistics, and found that a GRACE score of 125.5, as a cut-off, has high sensitivity and specificity in evaluating PCI possibilities in NSTE-ACS patients. Conclusions Our findings indicate that the GRACE score has predictive value in determining whether NSTE-ACS patients would receive PCI.

Myeloperoxidase-oxidized high density lipoprotein impairs atherosclerotic plaque stability by inhibiting smooth muscle cell migration.

BackgroundHigh density lipoprotein (HDL) has been proved to be a protective factor for coronary heart disease. Notably, HDL in atherosclerotic plaques can be nitrated (NO2-oxHDL) and chlorinated (Cl-oxHDL) by myeloperoxidase (MPO), likely compromising its cardiovascular protective effects.MethodHere we determined the effects of NO2-oxHDL and Cl-oxHDL on SMC migration using wound healing and transwell assays, proliferation using MTT and BrdU assays, and apoptosis using Annexin-V assay in vitro, as well as on atherosclerotic plaque stability in vivo using a coratid artery collar implantation mice model.ResultsOur results showed that native HDL promoted SMC proliferation and migration, whereas NO2-oxHDL and Cl-oxHDL inhibited SMC migration and reduced capacity of stimulating SMC proliferation as well as migration, respectively. OxHDL had no significant influence on SMC apoptosis. In addition, we found that ERK1/2-phosphorylation was significantly lower when SMCs were incubated with NO2-oxHDL and Cl-oxHDL. Furthermore, transwell experiments showed that differences between native HDL, NO2-oxHDL and Cl-oxHDL was abolished after PD98059 (MAPK kinase inhibitor) treatment. In aortic SMCs from scavenger receptor BI (SR-BI) deficient mice, differences between migration of native HDL, NO2-oxHDL and Cl-oxHDL treated SMCs vanished, indicating SR-BI’s possible role in HDL-associated SMC migration. Importantly, NO2-oxHDL and Cl-oxHDL induced neointima formation and reduced SMC positive staining cells in atherosclerotic plaque, resulting in elevated vulnerable index of atherosclerotic plaque.ConclusionThese findings implicate MPO-catalyzed oxidization of HDL may contribute to atherosclerotic plaque instability by inhibiting SMC proliferation and migration through MAPK-ERK pathway which was dependent on SR-BI.

Elevated plasma migration inhibitory factor in hypertension–hyperlipidemia patients correlates with impaired endothelial function

Abstract Migration inhibitory factor (MIF) has been shown to be critical in the pathology of early artherosclerosis; this article aim to investigate the plasma levels of MIF in hypertension plus hyperlipidemia patients. A total of 39 hypertension plus hyperlipidemia patients without any previous treatment were enrolled (HTN-HLP). Twenty-five healthy subjects were enrolled as the healthy control group (HEALTHY). Plasma MIF was measured by ELISA; laboratory and clinical characteristics were analyzed. HUVECs were treated with pooled plasma from HTN-HLP and HEALTHY groups, and the protein levels of adhesion molecules VCAM-1 and ICAM-1 were determined by ELISA. We found that plasma MIF was significantly elevated in the HTN-HLP group. Serum NO and eNOS levels were significantly lower; serum ET-1 (endothelin) levels were significantly higher in the HTN-HLP group. Furthermore, blood pressure, baPWV (brachial–ankle pulse wave velocity), and serum ET-1 level were significantly positively; serum NO and eNOS levels were negatively correlated with plasma MIF levels. Plasma from HTN-HLP significantly stimulated VCAM-1 and ICAM-1 protein expression on the surface of HUVECs. Plasma MIF was elevated in HTN-HLP patients and correlates with impaired endothelial function.