-
Journal of Cardiology May 2022Myocardial infarction (MI), a leading cause of death around the world, displays a complex pattern of inheritance. Previously, rare mutations in low-density lipoprotein...
OBJECTIVES
Myocardial infarction (MI), a leading cause of death around the world, displays a complex pattern of inheritance. Previously, rare mutations in low-density lipoprotein receptor (LDLR) genes and apolipoprotein A V (APOA5) have been shown to contribute to MI risk in individual families. Exosomes provide a potential source of biomarkers for MI. This study is to determine the role of LDLR and APOA5 as biomarkers for early diagnosis of MI.
METHODS
In this study, we detected the levels of LDLR, APOA5, and cardiac troponin T in plasma-derived exosomes in MI patients and age-matched healthy people by enzyme linked immunosorbent assay and observed the morphology and number of exosomes using transmission electron microscope and nanoparticle tracking analysis. Oxygen-glucose deprivation (OGD) method was used to induce MI in H9C2 cardiomyocytes to explore the effect of exosomes.
RESULTS
We found that the levels of LDLR and APOA5 in plasma-derived exosomes in MI patients were significantly decreased. Furthermore, exosomes of MI patients were significantly larger in size and the concentration of exosomes was higher than that of age-matched non-MI people. In vitro experiments showed that OGD treatment induced apoptosis of myocardial cells and decreased the expression of LDLR and APOA5, while addition of exosomes isolated from healthy people rescued these phenotypes.
CONCLUSION
Exosomal APOA5 and LDLR are intimately associated with MI, and thereby have the potential to function as diagnostic markers of MI.
Topics: Apolipoprotein A-V; Apolipoproteins; Biomarkers; Exosomes; Humans; Lipoproteins, LDL; Myocardial Infarction
PubMed: 35058120
DOI: 10.1016/j.jjcc.2021.10.020 -
Archives of Biochemistry and Biophysics Jan 2020Lipid nitration occurs during physiological and pathophysiological conditions, generating a variety of biomolecules capable to modulate inflammatory cell responses.... (Review)
Review
Lipid nitration occurs during physiological and pathophysiological conditions, generating a variety of biomolecules capable to modulate inflammatory cell responses. Low-density lipoprotein (LDL) oxidation has been extensively related to atherosclerotic lesion development while oxidative modifications confer the particle pro-atherogenic features. Herein, we reviewed the oxidation versus nitration of human LDL protein and lipid fractions. We propose that unsaturated fatty acids present in LDL can be nitrated under mild nitration conditions, suggesting an anti-atherogenic role for LDL carrying nitro-fatty acids (NFA).
Topics: Fatty Acids; Humans; Lipoproteins, LDL; Nitric Oxide; Oxidation-Reduction
PubMed: 31738891
DOI: 10.1016/j.abb.2019.108190 -
International Journal of Molecular... Nov 2022Neutrophil extracellular traps (NETs) are found in patients with various diseases, including cardiovascular diseases. We previously reported that copper-oxidized...
Neutrophil extracellular traps (NETs) are found in patients with various diseases, including cardiovascular diseases. We previously reported that copper-oxidized low-density lipoprotein (oxLDL) promotes NET formation of neutrophils, and that the resulting NETs increase the inflammatory responses of endothelial cells. In this study, we investigated the effects of high-density lipoproteins (HDL) on NET formation. HL-60-derived neutrophils were treated with phorbol 12-myristate 13-acetate (PMA) and further incubated with oxLDL and various concentrations of HDL for 2 h. NET formation was evaluated by quantifying extracellular DNA and myeloperoxidase. We found that the addition of native HDL partially decreased NET formation of neutrophils induced by oxLDL. This effect of HDL was lost when HDL was oxidized. We showed that oxidized phosphatidylcholines and lysophosphatidylcholine, which are generated in oxLDL, promoted NET formation of PMA-primed neutrophils, and NET formation by these products was completely blocked by native HDL. Furthermore, we found that an electronegative subfraction of LDL, LDL(-), which is separated from human plasma and is thought to be an in vivo oxLDL, was capable of promoting NET formation. These results suggest that plasma lipoproteins and their oxidative modifications play multiple roles in promoting NET formation, and that HDL acts as a suppressor of this response.
Topics: Humans; Lipoproteins, HDL; Extracellular Traps; Phospholipids; Endothelial Cells; Lipoproteins, LDL; Tetradecanoylphorbol Acetate
PubMed: 36430470
DOI: 10.3390/ijms232213992 -
Biomolecules Jan 2022Endocytosis is the process by which molecules are actively transported into cells. It can take on a variety of forms depending on the cellular machinery involved ranging... (Review)
Review
Endocytosis is the process by which molecules are actively transported into cells. It can take on a variety of forms depending on the cellular machinery involved ranging from specific receptor-mediated endocytosis to the less selective and actin-driven macropinocytosis. The plasma lipoproteins, which deliver lipids and other cargo to cells, have been intensely studied with respect to their endocytic uptake. One of the first molecules to be visualised undergoing endocytosis via a receptor-mediated, clathrin-dependent pathway was low-density lipoprotein (LDL). The LDL molecule has subsequently been shown to be internalised through multiple endocytic pathways. Dissecting the pathways of lipoprotein endocytosis has been crucial to understanding the regulation of plasma lipid levels and how lipids enter cells in the arterial wall to promote atherosclerosis. It has also aided understanding of the dysregulation that occurs in plasma lipid levels when molecules involved in uptake are defective, as is the case in familial hypercholesterolemia (FH). The aim of this review is to outline the many endocytic pathways utilised for lipoprotein uptake. It explores the various experimental approaches that have been applied to visualise lipoprotein endocytosis with an emphasis on LDL and its more complex counterpart, lipoprotein(a) [Lp(a)]. Finally, we look at new developments in lipoprotein visualisation that hold promise for scrutinising endocytic pathways to finer detail in the future.
Topics: Clathrin; Endocytosis; Humans; Hyperlipoproteinemia Type II; Lipoproteins; Lipoproteins, LDL
PubMed: 35204658
DOI: 10.3390/biom12020158 -
Journal of the American College of... Jan 2024
Topics: Humans; Lipoprotein(a); Apolipoproteins B; Lipoproteins, LDL
PubMed: 38233013
DOI: 10.1016/j.jacc.2023.11.008 -
Journal of Diabetes Investigation Oct 2023In diabetes, the impairment of insulin secretion and insulin resistance contribute to hypertriglyceridemia, as the enzymatic activity of lipoprotein lipase (LPL) depends... (Review)
Review
In diabetes, the impairment of insulin secretion and insulin resistance contribute to hypertriglyceridemia, as the enzymatic activity of lipoprotein lipase (LPL) depends on insulin action. The transport of LPL to endothelial cells and its enzymatic activity are maintained by the formation of lipolytic complex depending on the multiple positive (glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 [GPIHBP1], apolipoprotein C-II [APOC2], APOA5, heparan sulfate proteoglycan [HSPG], lipase maturation factor 1 [LFM1] and sel-1 suppressor of lin-12-like [SEL1L]) and negative regulators (APOC1, APOC3, angiopoietin-like proteins [ANGPTL]3, ANGPTL4 and ANGPTL8). Among the regulators, GPIHBP1 is a crucial molecule for the translocation of LPL from parenchymal cells to the luminal surface of capillary endothelial cells, and maintenance of lipolytic activity; that is, hydrolyzation of triglyceride into free fatty acids and monoglyceride, and conversion from chylomicron to chylomicron remnant in the exogenous pathway and from very low-density lipoprotein to low-density lipoprotein in the endogenous pathway. The null mutation of GPIHBP1 causes severe hypertriglyceridemia and pancreatitis, and GPIGBP1 autoantibody syndrome also causes severe hypertriglyceridemia and recurrent episodes of acute pancreatitis. In patients with type 2 diabetes, the elevated serum triglyceride levels negatively correlate with circulating LPL levels, and positively with circulating APOC1, APOC3, ANGPTL3, ANGPTL4 and ANGPTL8 levels. In contrast, circulating GPIHBP1 levels are not altered in type 2 diabetes patients with higher serum triglyceride levels, whereas they are elevated in type 2 diabetes patients with diabetic retinopathy and nephropathy. The circulating regulators of lipolytic complex might be new biomarkers for lipid and glucose metabolism, and diabetic vascular complications.
Topics: Humans; Glycosylphosphatidylinositols; Diabetes Mellitus, Type 2; Endothelial Cells; Acute Disease; Pancreatitis; Hypertriglyceridemia; Carrier Proteins; Triglycerides; Lipoproteins, LDL; Lipoproteins, HDL; Angiopoietin-Like Protein 3; Proteins
PubMed: 37448184
DOI: 10.1111/jdi.14056 -
Current Opinion in Lipidology Oct 2019The two major challenges in cardiovascular medicine are to refine risk prediction and to improve pharmacological prevention and treatment. The concept of innate immune... (Review)
Review
PURPOSE OF REVIEW
The two major challenges in cardiovascular medicine are to refine risk prediction and to improve pharmacological prevention and treatment. The concept of innate immune memory, which is called trained immunity, has the potential to improve clinical practice in these regards.
RECENT FINDINGS
Monocytes and macrophages have the capability to develop a long-term proinflammatory and proatherogenic phenotype after brief exposure to inflammatory stimuli, such as oxidized low-density lipoprotein particles. This innate immune memory develops because of rewiring of intracellular metabolic pathways and epigenetic reprogramming of histone modifications. The persistence of circulating hyperresponsive monocytes in vivo is explained by the fact that training occurs in myeloid progenitor cells in the bone marrow. Several recent studies reported the presence of monocytes with a trained immune phenotype in patients with established atherosclerosis, and in patients with an increased risk for atherosclerosis because of dyslipoproteinemia.
SUMMARY
In monocytes and their bone marrow progenitors, metabolic and epigenetic reprogramming can induce trained immunity, which might contribute to the persistent nonresolving inflammation that characterizes atherosclerosis. These pathways offer exciting novel drug targets to improve the prevention and treatment of cardiovascular disease.
Topics: Atherosclerosis; Bone Marrow Cells; Cardiovascular Diseases; Epigenesis, Genetic; Humans; Immunity, Innate; Inflammation; Lipoproteins, LDL; Macrophages; Monocytes; Myeloid Progenitor Cells
PubMed: 31335332
DOI: 10.1097/MOL.0000000000000628 -
Immunology Letters Nov 2023Efferocytosis dysfunction contributes to the progression and rupture of atherosclerotic plaques. Efferocytosis is crucially modulated by intracytoplasmic Ca, and...
OBJECTIVE
Efferocytosis dysfunction contributes to the progression and rupture of atherosclerotic plaques. Efferocytosis is crucially modulated by intracytoplasmic Ca, and mitochondrial calcium uniporter (MCU) complex proteins serve as key channels for regulating Ca concentration. Therefore, it was speculated that MCU may affect the development of atherosclerosis (AS) by regulating efferocytosis. In the present study, we aimed to investigate whether MCU could affect foam cell formation by regulating efferocytosis.
METHODS
We stimulated primary macrophages (Møs) using oxidized low-density lipoprotein (ox-LDL) to mimic the atherosclerotic microenvironment and treated them with Ru360, an MCU-specific inhibitor, and UNC1062, an inhibitor of efferocytosis. Additionally, we conducted double staining to determine the Mø efferocytosis rate. We measured the expression of MCU complexes and efferocytosis-associated proteins using western blotting (WB) and real-time quantitative polymerase chain reaction (RT-qPCR), respectively. In addition, we separately detected the Ca level in the cytoplasm and mitochondria (MT) using Fluo-4 AM and Rhod-2 methods. We separately determined the reactive oxygen species (ROS) level in cytoplasm and MT using dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probing method and Mito-SOXTM superoxide indicator staining. Additionally, we conducted the enzyme-linked immunosorbent assay (ELISA) to detect the production of interleukin-6 (IL-6), interleukin-18 (IL-18), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α). Oil Red O staining was performed to measure cytoplasmic lipid levels.
RESULTS
Ru360 attenuated ox-LDL-induced efferocytosis dysfunction, and attenuated the upregulation of MCU and MCUR1 induced by ox-LDL, and meanwhile attenuated the downregulation of MCUb induced by ox-LDL. Ru360 attenuated the decrease of intracytoplasmic Ca concentration induced by ox- LDL, Ru360 also attenuated the ROS production induced by ox- LDL, attenuated the release of IL-6, IL-18, IL-1β, and TNF-α induced by ox- LDL, and attenuated the increase of intracytoplasmic lipid content induced by ox-LDL. UNC1062 attenuated the effects of Ru360 in reducing inflammatory cytokines and intracytoplasmic lipid content.
CONCLUSIONS
In this study, we found that MCU inhibition modulated intracytoplasmic Ca concentration, improved impaired Mø efferocytosis, and reduced ROS generation. Macrophage efferocytosis removed apoptotic cells and prevented the release of inflammatory factor and foam cell formation, and this can be a potential new therapeutic target for alleviating atherosclerosis.
Topics: Animals; Mice; Reactive Oxygen Species; Interleukin-18; Tumor Necrosis Factor-alpha; Interleukin-6; Disease Models, Animal; Macrophages; Lipoproteins, LDL; Atherosclerosis
PubMed: 37689315
DOI: 10.1016/j.imlet.2023.09.003 -
Pharmacological Research Oct 2021Cardiovascular disease is one of the leading causes of mortality globally. Atherosclerosis is an important step towards different types of cardiovascular disease. The... (Review)
Review
Cardiovascular disease is one of the leading causes of mortality globally. Atherosclerosis is an important step towards different types of cardiovascular disease. The role of oxidized low-density lipoprotein (oxLDL) in the initiation and progression of atherosclerosis has been thoroughly investigated in recent years. Moreover, clinical trials have established that diabetic patients are at a greater risk of developing atherosclerotic plaques. Hence, we aimed to review the clinical and experimental impacts of various classes of antidiabetic drugs on the circulating levels of oxLDL. Metformin, pioglitazone, and dipeptidyl peptidase-4 inhibitors were clinically associated with a suppressive effect on oxLDL in patients with impaired glucose tolerance. However, there is an insufficient number of studies that have clinically evaluated the relationship between oxLDL and newer agents such as agonists of glucagon-like peptide 1 receptor or inhibitors of sodium-glucose transport protein 2. Next, we attempted to explore the multitude of mechanisms that antidiabetic agents exert to counter the undesirable effects of oxLDL in macrophages, endothelial cells, and vascular smooth muscle cells. In general, antidiabetic drugs decrease the uptake of oxLDL by vascular cells and reduce subsequent inflammatory signaling, which prevents macrophage adhesion and infiltration. Moreover, these agents suppress the oxLDL-induced transformation of macrophages into foam cells by either inhibiting oxLDL entrance, or by facilitating its efflux. Thus, the anti-inflammatory, anti-oxidant, and anti-apoptotic properties of antidiabetic agents abrogate changes induced by oxLDL, which can be extremely beneficial in controlling atherosclerosis in diabetic patients.
Topics: Animals; Atherosclerosis; Humans; Hypoglycemic Agents; Lipoproteins, LDL
PubMed: 34400317
DOI: 10.1016/j.phrs.2021.105819 -
Arteriosclerosis, Thrombosis, and... Oct 2019Vascular calcification (VC) is strongly associated with all-cause mortality and is an independent predictor of cardiovascular events. Resulting from its complex,... (Review)
Review
Vascular calcification (VC) is strongly associated with all-cause mortality and is an independent predictor of cardiovascular events. Resulting from its complex, multifaceted nature, targeted treatments for VC have not yet been developed. Lipoproteins are well characterized in the pathogenesis of atherosclerotic plaques, leading to the development of plaque regressing therapeutics. Although their roles in plaque progression are well documented, their roles in VC, and calcification of a plaque, are not well understood. In this review, early in vitro data and clinical correlations suggest an inhibitory role for HDL (high-density lipoproteins) in VC, a stimulatory role for LDL (low-density lipoprotein) and VLDL (very low-density lipoprotein) and a potentially causal role for Lp(a) (lipoprotein [a]). Additionally, after treatment with a statin or PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor, plaque calcification is observed to increase. With the notion that differing morphologies of plaque calcification associate with either a more stable or unstable plaque phenotype, uncovering the mechanisms of lipoprotein-artery wall interactions could produce targeted therapeutic options for VC.
Topics: Calcinosis; Cardiovascular Diseases; Disease Progression; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lipoproteins, LDL; Lipoproteins, VLDL; Plaque, Atherosclerotic; Prognosis; Risk Assessment; Role; Survival Analysis
PubMed: 31462089
DOI: 10.1161/ATVBAHA.119.311574