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Sharma M, Bakshi AK, Mittapelly N, Gautam S, Marwaha D, Rai N, Singh N, Tiwari P, Aggarwal N, Kumar A, Mishra PR. Recent updates on innovative approaches to overcome drug resistance for better outcomes in cancer. J Control Release 2022; 346:43-70. [DOI: 10.1016/j.jconrel.2022.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 02/07/2023]
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2
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Lorey MB, Öörni K, Kovanen PT. Modified Lipoproteins Induce Arterial Wall Inflammation During Atherogenesis. Front Cardiovasc Med 2022; 9:841545. [PMID: 35310965 PMCID: PMC8927694 DOI: 10.3389/fcvm.2022.841545] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/26/2022] [Indexed: 12/15/2022] Open
Abstract
Circulating apolipoprotein B-containing lipoproteins, notably the low-density lipoproteins, enter the inner layer of the arterial wall, the intima, where a fraction of them is retained and modified by proteases, lipases, and oxidizing agents and enzymes. The modified lipoproteins and various modification products, such as fatty acids, ceramides, lysophospholipids, and oxidized lipids induce inflammatory reactions in the macrophages and the covering endothelial cells, initiating an increased leukocyte diapedesis. Lipolysis of the lipoproteins also induces the formation of cholesterol crystals with strong proinflammatory properties. Modified and aggregated lipoproteins, cholesterol crystals, and lipoproteins isolated from human atherosclerotic lesions, all can activate macrophages and thereby induce the secretion of proinflammatory cytokines, chemokines, and enzymes. The extent of lipoprotein retention, modification, and aggregation have been shown to depend largely on differences in the composition of the circulating lipoprotein particles. These properties can be modified by pharmacological means, and thereby provide opportunities for clinical interventions regarding the prevention and treatment of atherosclerotic vascular diseases.
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Affiliation(s)
- Martina B. Lorey
- Atherosclerosis Research Laboratory, Wihuri Research Institute, Helsinki, Finland
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Katariina Öörni
- Atherosclerosis Research Laboratory, Wihuri Research Institute, Helsinki, Finland
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- *Correspondence: Katariina Öörni
| | - Petri T. Kovanen
- Atherosclerosis Research Laboratory, Wihuri Research Institute, Helsinki, Finland
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Wang K, Gan C, Wang H, Ao M, Fan Y, Chen Y. AFM detects the effects of acidic condition on the size and biomechanical properties of native/oxidized low-density lipoprotein. Colloids Surf B Biointerfaces 2021; 208:112053. [PMID: 34438294 DOI: 10.1016/j.colsurfb.2021.112053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 07/06/2021] [Accepted: 08/16/2021] [Indexed: 12/18/2022]
Abstract
Solution acidification exists under some physiological conditions (e.g. lysosomes in cells) and diseases (e.g. atherosclerosis, tumors, etc.). It is poorly understood whether and how acidification influences the size and biomechanical (stiffness and stickiness) properties of native Low-density lipoprotein (LDL) and its oxidized form (oxLDL) which plays a vital role in atherogenesis and tumorigenesis. Atomic force microscopy (AFM) evaluated that gradient acidification from pH 7.4 to pH 4.4 caused an expanding-first-and-then-shrinking decrease in size and a dramatic decrease in stiffness (but no statistically significant changes in stickiness) of LDL/oxLDL particles by influencing secondary/tertiary structures and lipid release detected by infrared spectral analysis and cholesterol detection, respectively. The smaller and softer characteristics of LDL/oxLDL at acidic conditions versus at the neutral pH partially explains the atherogenic role of acidification. The data may provide important information for a better understanding of LDL/oxLDL and some diseases (e.g. atherosclerosis and tumors).
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Affiliation(s)
- Kun Wang
- Jiangxi Key Laboratory for Microscale interdisciplinary Study, Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi, 330031, PR China; School of Materials Science and Engineering, Nanchang University, Nanchang, Jiangxi, PR China
| | - Chaoye Gan
- Jiangxi Key Laboratory for Microscale interdisciplinary Study, Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi, 330031, PR China
| | - Huaying Wang
- Jiangxi Key Laboratory for Microscale interdisciplinary Study, Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi, 330031, PR China
| | - Meiying Ao
- School of Basic Medical Sciences, Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, 330025, PR China
| | - Youlong Fan
- School of Basic Medical Sciences, Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi, 330025, PR China
| | - Yong Chen
- Jiangxi Key Laboratory for Microscale interdisciplinary Study, Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi, 330031, PR China.
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Lysophosphatidylcholine in phospholipase A 2-modified LDL triggers secretion of angiopoietin 2. Atherosclerosis 2021; 327:87-99. [PMID: 34020784 DOI: 10.1016/j.atherosclerosis.2021.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/09/2021] [Accepted: 04/13/2021] [Indexed: 01/30/2023]
Abstract
BACKGROUND AND AIMS Secretory phospholipase A2 (PLA2) hydrolyzes LDL phospholipids generating modified LDL particles (PLA2-LDL) with increased atherogenic properties. Exocytosis of Weibel-Palade bodies (WPB) releases angiopoietin 2 (Ang2) and externalizes P-selectin, which both play important roles in vascular inflammation. Here, we investigated the effects of PLA2-LDL on exocytosis of WPBs. METHODS Human coronary artery endothelial cells (HCAECs) were stimulated with PLA2- LDL, and its uptake and effect on Ang2 release, leukocyte adhesion, and intracellular calcium levels were measured. The effects of PLA2-LDL on Ang2 release and WPB exocytosis were measured in and ex vivo in mice. RESULTS Exposure of HCAECs to PLA2-LDL triggered Ang2 secretion and promoted leukocyte-HCAEC interaction. Lysophosphatidylcholine was identified as a critical component of PLA2-LDL regulating the WPB exocytosis, which was mediated by cell-surface proteoglycans, phospholipase C, intracellular calcium, and cytoskeletal remodeling. PLA2-LDL also induced murine endothelial WPB exocytosis in blood vessels in and ex vivo, as evidenced by secretion of Ang2 in vivo, P-selectin translocation to plasma membrane in intact endothelial cells in thoracic artery and tracheal vessels, and reduced Ang2 staining in tracheal endothelial cells. Finally, in contrast to normal human coronary arteries, in which Ang2 was present only in the endothelial layer, at sites of advanced atherosclerotic lesions, Ang2 was detected also in the intima, media, and adventitia. CONCLUSIONS Our studies reveal PLA2-LDL as a potent agonist of endothelial WPB exocytosis, resulting in increased secretion of Ang2 and translocation of P-selectin. The results provide mechanistic insight into PLA2-LDL-dependent promotion of vascular inflammation and atherosclerosis.
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Jayaraman S, Fändrich M, Gursky O. Synergy between serum amyloid A and secretory phospholipase A 2. eLife 2019; 8:46630. [PMID: 31111824 PMCID: PMC6557629 DOI: 10.7554/elife.46630] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/14/2019] [Indexed: 12/30/2022] Open
Abstract
Serum amyloid A (SAA) is an evolutionally conserved enigmatic biomarker of inflammation. In acute inflammation, SAA plasma levels increase ~1,000 fold, suggesting that this protein family has a vital beneficial role. SAA increases simultaneously with secretory phospholipase A2 (sPLA2), compelling us to determine how SAA influences sPLA2 hydrolysis of lipoproteins. SAA solubilized phospholipid bilayers to form lipoproteins that provided substrates for sPLA2. Moreover, SAA sequestered free fatty acids and lysophospholipids to form stable proteolysis-resistant complexes. Unlike albumin, SAA effectively removed free fatty acids under acidic conditions, which characterize inflammation sites. Therefore, SAA solubilized lipid bilayers to generate substrates for sPLA2 and removed its bioactive products. Consequently, SAA and sPLA2 can act synergistically to remove cellular membrane debris from injured sites, which is a prerequisite for tissue healing. We postulate that the removal of lipids and their degradation products constitutes a vital primordial role of SAA in innate immunity; this role remains to be tested in vivo. Cell boundaries are made up of fatty substances known as lipids. When cells get severely damaged, their lipid membranes break apart. These broken fragments of membrane become highly toxic, and must be removed as soon as possible to allow the tissue to heal. A small protein called serum amyloid A, SAA for short, was recently proposed to play a pivotal role in this process. In humans, SAA levels in the blood rapidly spike to over a thousand times their normal level following inflammation, injury or infection. Combined with the fact SAA has been conserved for over 500 million years, this suggests that SAA must be important for survival. But, it is not entirely clear how this protein works. One clue for how SAA works is its relationship to another ancient protein called secretory phospholipase A2. This protein, also known as sPLA2, is part of a big family of enzymes that break down lipids in the cell membrane. Notably, sPLA2 levels rise at the same time and place as SAA during inflammation. This led Jayaraman et al. to ask whether SAA and sPLA2 might be working together to clean up the cell membrane debris. To find out, Jayaraman et al. mixed mouse SAA with vesicles of membrane lipids, and then added sPLA2. This revealed that SAA reshapes the lipid membrane into smaller ‘nanoparticles’ with tightly curved surfaces that are easier for sPLA2 to break down. As the sPLA2 breaks up these particles, SAA then gathers up and gets rid of the leftover toxic fragments. This suggests that SAA has two roles: helping sPLA2 break down the membrane, and removing any toxic debris. Clearing debris after injury is essential for proper healing. So, understanding how it works is crucial to find new ways to treat inflammation. Further work to understand SAA and sPLA2 could improve our understanding of how to treat acute and chronic inflammation and its life-threatening complications.
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Affiliation(s)
- Shobini Jayaraman
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, United States
| | - Marcus Fändrich
- Institute of Protein Biochemistry, Ulm University, Ulm, Germany
| | - Olga Gursky
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, United States.,Amyloidosis Treatment and Research Center, Boston University School of Medicine, Boston, United States
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Öörni K, Lehti S, Sjövall P, Kovanen PT. Triglyceride-Rich Lipoproteins as a Source of Proinflammatory Lipids in the Arterial Wall. Curr Med Chem 2019; 26:1701-1710. [DOI: 10.2174/0929867325666180530094819] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/27/2017] [Accepted: 01/01/2018] [Indexed: 12/11/2022]
Abstract
Apolipoprotein B –containing lipoproteins include triglyceride-rich lipoproteins
(chylomicrons and their remnants, and very low-density lipoproteins and their remnants) and
cholesterol-rich low-density lipoprotein particles. Of these, lipoproteins having sizes below
70-80 nm may enter the arterial wall, where they accumulate and induce the formation of
atherosclerotic lesions. The processes that lead to accumulation of lipoprotein-derived lipids
in the arterial wall have been largely studied with a focus on the low-density lipoprotein particles.
However, recent observational and genetic studies have discovered that the triglyceriderich
lipoproteins and their remnants are linked with cardiovascular disease risk. In this review,
we describe the potential mechanisms by which the triglyceride-rich remnant lipoproteins can
contribute to the development of atherosclerotic lesions, and highlight the differences in the
atherogenicity between low-density lipoproteins and the remnant lipoproteins.
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Affiliation(s)
| | - Satu Lehti
- Wihuri Research Institute, Helsinki, Finland
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Connelly MA, Shimizu C, Winegar DA, Shalaurova I, Pourfarzib R, Otvos JD, Kanegaye JT, Tremoulet AH, Burns JC. Differences in GlycA and lipoprotein particle parameters may help distinguish acute kawasaki disease from other febrile illnesses in children. BMC Pediatr 2016; 16:151. [PMID: 27596163 PMCID: PMC5011873 DOI: 10.1186/s12887-016-0688-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/19/2016] [Indexed: 02/08/2023] Open
Abstract
Background Glycosylation patterns of serum proteins, such as α1-acid glycoprotein, are modified during an acute phase reaction. The response of acute Kawasaki disease (KD) patients to IVIG treatment has been linked to sialic acid levels on native IgG, suggesting that protein glycosylation patterns vary during the immune response in acute KD. Additionally, the distribution and function of lipoprotein particles are altered during inflammation. Therefore, the aim of this study was to explore the potential for GlycA, a marker of protein glycosylation, and the lipoprotein particle profile to distinguish pediatric patients with acute KD from those with other febrile illnesses. Methods Nuclear magnetic resonance was used to quantify GlycA and lipoprotein particle classes and subclasses in pediatric subjects with acute KD (n = 75), post-treatment subacute (n = 36) and convalescent (n = 63) KD, as well as febrile controls (n = 48), and age-similar healthy controls (n = 48). Results GlycA was elevated in acute KD subjects compared to febrile controls with bacterial or viral infections, IVIG-treated subacute and convalescent KD subjects, and healthy children (P <0.0001). Acute KD subjects had increased total and small low density lipoprotein particle numbers (LDL-P) (P <0.0001) and decreased total high density lipoprotein particle number (HDL-P) (P <0.0001) compared to febrile controls. Consequently, the ratio of LDL-P to HDL-P was higher in acute KD subjects than all groups tested (P <0.0001). While GlycA, CRP, erythrocyte sedimentation rate, LDL-P and LDL-P/HDL-P ratio were able to distinguish patients with KD from those with other febrile illnesses (AUC = 0.789–0.884), the combinations of GlycA and LDL-P (AUC = 0.909) or GlycA and the LDL-P/HDL-P ratio (AUC = 0.910) were best at discerning KD in patients 6–10 days after illness onset. Conclusions High levels of GlycA confirm enhanced protein glycosylation as part of the acute phase response in KD patients. When combined with common laboratory tests and clinical characteristics, GlycA and NMR-measured lipoprotein particle parameters may be useful for distinguishing acute KD from bacterial or viral illnesses in pediatric patients. Electronic supplementary material The online version of this article (doi:10.1186/s12887-016-0688-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Margery A Connelly
- LipoScience, Laboratory Corporation of America® Holdings, 2500 Sumner Blvd, Raleigh, NC, 27616, USA.
| | - Chisato Shimizu
- Department of Pediatrics, University of California, San Diego, CA, USA
| | - Deborah A Winegar
- LipoScience, Laboratory Corporation of America® Holdings, 2500 Sumner Blvd, Raleigh, NC, 27616, USA
| | - Irina Shalaurova
- LipoScience, Laboratory Corporation of America® Holdings, 2500 Sumner Blvd, Raleigh, NC, 27616, USA
| | - Ray Pourfarzib
- LipoScience, Laboratory Corporation of America® Holdings, 2500 Sumner Blvd, Raleigh, NC, 27616, USA
| | - James D Otvos
- LipoScience, Laboratory Corporation of America® Holdings, 2500 Sumner Blvd, Raleigh, NC, 27616, USA
| | - John T Kanegaye
- Department of Pediatrics, University of California, San Diego, CA, USA.,Rady Children's Hospital, San Diego, CA, USA
| | - Adriana H Tremoulet
- Department of Pediatrics, University of California, San Diego, CA, USA.,Rady Children's Hospital, San Diego, CA, USA
| | - Jane C Burns
- Department of Pediatrics, University of California, San Diego, CA, USA.,Rady Children's Hospital, San Diego, CA, USA
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Thermal stability of human plasma electronegative low-density lipoprotein: A paradoxical behavior of low-density lipoprotein aggregation. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1015-1024. [PMID: 27233433 DOI: 10.1016/j.bbalip.2016.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/08/2016] [Accepted: 05/21/2016] [Indexed: 12/20/2022]
Abstract
Low-density lipoprotein (LDL) aggregation is central in triggering atherogenesis. A minor fraction of electronegative plasma LDL, termed LDL(-), plays a special role in atherogenesis. To better understand this role, we analyzed the kinetics of aggregation, fusion and disintegration of human LDL and its fractions, LDL(+) and LDL(-). Thermal denaturation of LDL was monitored by spectroscopy and electron microscopy. Initially, LDL(-) aggregated and fused faster than LDL(+), but later the order reversed. Most LDL(+) disintegrated and precipitated upon prolonged heating. In contrast, LDL(-) partially retained lipoprotein morphology and formed soluble aggregates. Biochemical analysis of all fractions showed no significant degradation of major lipids, mild phospholipid oxidation, and an increase in non-esterified fatty acid (NEFA) upon thermal denaturation. The main baseline difference between LDL subfractions was higher content of NEFA in LDL(-). Since NEFA promote lipoprotein fusion, increased NEFA content can explain rapid initial aggregation and fusion of LDL(-) but not its resistance to extensive disintegration. Partial hydrolysis of apoB upon heating was similar in LDL subfractions, suggesting that minor proteins importantly modulate LDL disintegration. Unlike LDL(+), LDL(-) contains small amounts of apoA-I and apoJ. Addition of exogenous apoA-I to LDL(+) hampered lipoprotein aggregation, fusion and precipitation, while depletion of endogenous apoJ had an opposite effect. Therefore, the initial rapid aggregation of LDL(-) is apparently counterbalanced by the stabilizing effects of minor proteins such as apoA-I and apoJ. These results help identify key determinants for LDL aggregation, fusion and coalescence into lipid droplets in vivo.
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Ahn HY, Kim M, Ahn YT, Sim JH, Choi ID, Lee SH, Lee JH. The triglyceride-lowering effect of supplementation with dual probiotic strains, Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032: Reduction of fasting plasma lysophosphatidylcholines in nondiabetic and hypertriglyceridemic subjects. Nutr Metab Cardiovasc Dis 2015; 25:724-733. [PMID: 26044516 DOI: 10.1016/j.numecd.2015.05.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 04/30/2015] [Accepted: 05/02/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS This study evaluated the triglyceride (TG)-lowering effects of consuming dual probiotic strains of Lactobacillus curvatus (L. curvatus) HY7601 and Lactobacillus plantarum (L. plantarum) KY1032 on the fasting plasma metabolome. METHODS AND RESULTS A randomized, double-blind, placebo-controlled study was conducted on 92 participants with hypertriglyceridemia but without diabetes. Over a 12-week testing period, the probiotic group consumed 2 g of powder containing 5 × 10(9) colony-forming units (cfu) of L. curvatus HY7601 and 5 × 10(9) cfu of L. plantarum KY1032 each day, whereas the placebo group consumed the same product without probiotics. Fasting plasma metabolomes were profiled using UPLC-LTQ-Orbitrap MS. After 12 weeks of treatment, the probiotic group displayed a 20% reduction (p = 0.001) in serum TGs and 25% increases (p=0.001) in apolipoprotein A-V (apoA-V). At the 12-week follow-up assessment, the following 11 plasma metabolites were significantly reduced in the probiotic group than the placebo group: palmitoleamide, palmitic amide, oleamide, and lysophosphatidyl choline (lysoPC) containing C14:0, C16:1, C16:0, C17:0, C18:3, C18:2, C18:1, and C20:3. In the probiotic group, changes (▵) in TG were negatively correlated with ▵ apoA-V, which was positively correlated with ▵ FFA. In addition, ▵ FFA was strongly and positively correlated with ▵ lysoPCs in the probiotic group but not the placebo group. CONCLUSIONS The triglyceride-lowering effects of probiotic supplementation, partly through elevated apoA-V, in borderline to moderate hypertriglyceridemic subjects showed reductions in plasma metabolites, fatty acid primary amides and lysoPCs (NCT02215694; http://www.clinicaltrials.gov). Clinical trials: NCT02215694; http://www.clinicaltrials.gov.
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Affiliation(s)
- H Y Ahn
- Interdisciplinary Course of Science for Aging, Yonsei University, Seoul, South Korea
| | - M Kim
- Research Center for Silver Science, Institute of Symbiotic Life-TECH, Yonsei University, Seoul, South Korea
| | - Y-T Ahn
- Korea Yakult Co., Ltd., Yongin, Gyeonggi, South Korea
| | - J-H Sim
- Korea Yakult Co., Ltd., Yongin, Gyeonggi, South Korea
| | - I-D Choi
- Korea Yakult Co., Ltd., Yongin, Gyeonggi, South Korea
| | - S-H Lee
- Department of Family Practice, National Health Insurance Corporation Ilsan Hospital, Goyang, South Korea
| | - J H Lee
- Research Center for Silver Science, Institute of Symbiotic Life-TECH, Yonsei University, Seoul, South Korea; National Leading Research Laboratory of Clinical Nutrigenetics/Nutrigenomics, Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, South Korea; Department of Food and Nutrition, Brain Korea 21 PLUS Project, College of Human Ecology, Yonsei University, Seoul, South Korea.
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Lu M, Gursky O. Aggregation and fusion of low-density lipoproteins in vivo and in vitro. Biomol Concepts 2015; 4:501-18. [PMID: 25197325 DOI: 10.1515/bmc-2013-0016] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Low-density lipoproteins (LDLs, also known as 'bad cholesterol') are the major carriers of circulating cholesterol and the main causative risk factor of atherosclerosis. Plasma LDLs are 20- to 25-nm nanoparticles containing a core of cholesterol esters surrounded by a phospholipid monolayer and a single copy of apolipoprotein B (550 kDa). An early sign of atherosclerosis is the accumulation of LDL-derived lipid droplets in the arterial wall. According to the widely accepted 'response-to-retention hypothesis', LDL binding to the extracellular matrix proteoglycans in the arterial intima induces hydrolytic and oxidative modifications that promote LDL aggregation and fusion. This enhances LDL uptake by the arterial macrophages and triggers a cascade of pathogenic responses that culminate in the development of atherosclerotic lesions. Hence, LDL aggregation, fusion, and lipid droplet formation are important early steps in atherogenesis. In vitro, a variety of enzymatic and nonenzymatic modifications of LDL can induce these reactions and thereby provide useful models for their detailed analysis. Here, we summarize current knowledge of the in vivo and in vitro modifications of LDLs leading to their aggregation, fusion, and lipid droplet formation; outline the techniques used to study these reactions; and propose a molecular mechanism that underlies these pro-atherogenic processes. Such knowledge is essential in identifying endogenous and exogenous factors that can promote or prevent LDL aggregation and fusion in vivo and to help establish new potential therapeutic targets to decelerate or even block these pathogenic reactions.
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Affiliation(s)
- Mengxiao Lu
- Department of Physiology and Biophysics, Boston University School of Medicine, W321, 700 Albany Street, Boston, MA 02118, USA.
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RETRACTED: Macrophage phenotypic plasticity in atherosclerosis: The associated features and the peculiarities of the expression of inflammatory genes. Int J Cardiol 2015; 184:436-445. [DOI: 10.1016/j.ijcard.2015.03.055] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 01/07/2015] [Accepted: 03/03/2015] [Indexed: 01/28/2023]
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Öörni K, Rajamäki K, Nguyen SD, Lähdesmäki K, Plihtari R, Lee-Rueckert M, Kovanen PT. Acidification of the intimal fluid: the perfect storm for atherogenesis. J Lipid Res 2014; 56:203-14. [PMID: 25424004 DOI: 10.1194/jlr.r050252] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Atherosclerotic lesions are often hypoxic and exhibit elevated lactate concentrations and local acidification of the extracellular fluids. The acidification may be a consequence of the abundant accumulation of lipid-scavenging macrophages in the lesions. Activated macrophages have a very high energy demand and they preferentially use glycolysis for ATP synthesis even under normoxic conditions, resulting in enhanced local generation and secretion of lactate and protons. In this review, we summarize our current understanding of the effects of acidic extracellular pH on three key players in atherogenesis: macrophages, apoB-containing lipoproteins, and HDL particles. Acidic extracellular pH enhances receptor-mediated phagocytosis and antigen presentation by macrophages and, importantly, triggers the secretion of proinflammatory cytokines from macrophages through activation of the inflammasome pathway. Acidity enhances the proteolytic, lipolytic, and oxidative modifications of LDL and other apoB-containing lipoproteins, and strongly increases their affinity for proteoglycans, and may thus have major effects on their retention and the ensuing cellular responses in the arterial intima. Finally, the decrease in the expression of ABCA1 at acidic pH may compromise cholesterol clearance from atherosclerotic lesions. Taken together, acidic extracellular pH amplifies the proatherogenic and proinflammatory processes involved in atherogenesis.
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Umaerus M, Rosengren B, Fagerberg B, Hurt-Camejo E, Camejo G. HDL2 interferes with LDL association with arterial proteoglycans: A possible athero-protective effect. Atherosclerosis 2012; 225:115-20. [DOI: 10.1016/j.atherosclerosis.2012.08.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 08/06/2012] [Accepted: 08/31/2012] [Indexed: 02/06/2023]
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14
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Lu M, Gantz DL, Herscovitz H, Gursky O. Kinetic analysis of thermal stability of human low density lipoproteins: a model for LDL fusion in atherogenesis. J Lipid Res 2012; 53:2175-2185. [PMID: 22855737 DOI: 10.1194/jlr.m029629] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fusion of modified LDL in the arterial wall promotes atherogenesis. Earlier we showed that thermal denaturation mimics LDL remodeling and fusion, and revealed kinetic origin of LDL stability. Here we report the first quantitative analysis of LDL thermal stability. Turbidity data show sigmoidal kinetics of LDL heat denaturation, which is unique among lipoproteins, suggesting that fusion is preceded by other structural changes. High activation energy of denaturation, E(a) = 100 ± 8 kcal/mol, indicates disruption of extensive packing interactions in LDL. Size-exclusion chromatography, nondenaturing gel electrophoresis, and negative-stain electron microscopy suggest that LDL dimerization is an early step in thermally induced fusion. Monoclonal antibody binding suggests possible involvement of apoB N-terminal domain in early stages of LDL fusion. LDL fusion accelerates at pH < 7, which may contribute to LDL retention in acidic atherosclerotic lesions. Fusion also accelerates upon increasing LDL concentration in near-physiologic range, which likely contributes to atherogenesis. Thermal stability of LDL decreases with increasing particle size, indicating that the pro-atherogenic properties of small dense LDL do not result from their enhanced fusion. Our work provides the first kinetic approach to measuring LDL stability and suggests that lipid-lowering therapies that reduce LDL concentration but increase the particle size may have opposite effects on LDL fusion.
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Affiliation(s)
- Mengxiao Lu
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118.
| | - Donald L Gantz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Haya Herscovitz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Olga Gursky
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118.
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Lähdesmäki K, Öörni K, Alanne-Kinnunen M, Jauhiainen M, Hurt-Camejo E, Kovanen PT. Acidity and lipolysis by group V secreted phospholipase A2 strongly increase the binding of apoB-100-containing lipoproteins to human aortic proteoglycans. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:257-67. [DOI: 10.1016/j.bbalip.2011.10.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 10/11/2011] [Accepted: 10/17/2011] [Indexed: 11/16/2022]
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Abstract
PURPOSE OF REVIEW The accumulation of macrophages in the vascular wall is a hallmark of atherosclerosis. The biological properties of atherosclerotic plaque macrophages determine lesion size, composition, and stability. In atherosclerotic plaques, macrophages encounter a microenvironment that comprises a variety of lipid oxidation products, each of which has diverse biological effects. In this review, we summarize recent advances in our understanding of the effects of plaque lipids on macrophage phenotypic polarization. RECENT FINDINGS Atherosclerotic lesions in mice and in humans contain various macrophage phenotypes, which play different roles in mediating inflammation, the clearance of dead cells, and possibly resolution. Macrophages alter their phenotype and biological function in response to plaque lipids through the upregulation of specific sets of genes. Interaction of oxidized lipids with pattern recognition receptors and activation of the inflammasome by cholesterol crystals drive macrophages toward an inflammatory M1 phenotype. A new phenotype, Mox, develops when oxidized phospholipids activate stress response genes via Nrf2. Other lipid mediators such as nitrosylated-fatty acids and omega-3 fatty acid-derived products polarize plaque macrophages toward anti-inflammatory and proresolving phenotypes. SUMMARY A deeper understanding of how lipids that accumulate in atherosclerotic plaques affect macrophage phenotype and function and thus atherosclerotic lesion development and stability will help to devise novel strategies for intervention.
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Affiliation(s)
| | - Norbert Leitinger
- Corresponding author: University of Virginia, Department of Pharmacology; 1340 Jefferson Park Avenue, Jordan Hall, 5th Floor, Rm 5036/5039, P.O. Box 800735, Charlottesville, VA 22908; Tel: 434-243-6363, Fax: 434-924-0149;
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Wang J, Cheng X, Xiang MX, Alanne-Kinnunen M, Wang JA, Chen H, He A, Sun X, Lin Y, Tang TT, Tu X, Sjöberg S, Sukhova GK, Liao YH, Conrad DH, Yu L, Kawakami T, Kovanen PT, Libby P, Shi GP. IgE stimulates human and mouse arterial cell apoptosis and cytokine expression and promotes atherogenesis in Apoe-/- mice. J Clin Invest 2011; 121:3564-77. [PMID: 21821913 DOI: 10.1172/jci46028] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 06/15/2011] [Indexed: 11/17/2022] Open
Abstract
IgE has a key role in the pathogenesis of allergic responses through its ability to activate mast cells via the receptor FcεR1. In addition to mast cells, many cell types implicated in atherogenesis express FcεR1, but whether IgE has a role in this disease has not been determined. Here, we demonstrate that serum IgE levels are elevated in patients with myocardial infarction or unstable angina pectoris. We found that IgE and the FcεR1 subunit FcεR1α were present in human atherosclerotic lesions and that they localized particularly to macrophage-rich areas. In mice, absence of FcεR1α reduced inflammation and apoptosis in atherosclerotic plaques and reduced the burden of disease. In cultured macrophages, the presence of TLR4 was required for FcεR1 activity. IgE stimulated the interaction between FcεR1 and TLR4, thereby inducing macrophage signal transduction, inflammatory molecule expression, and apoptosis. These IgE activities were reduced in the absence of FcεR1 or TLR4. Furthermore, IgE activated macrophages by enhancing Na+/H+ exchanger 1 (NHE1) activity. Inactivation of NHE1 blocked IgE-induced macrophage production of inflammatory molecules and apoptosis. Cultured human aortic SMCs (HuSMCs) and ECs also exhibited IgE-induced signal transduction, cytokine expression, and apoptosis. In human atherosclerotic lesions, SMCs and ECs colocalized with IgE and TUNEL staining. This study reveals what we believe to be several previously unrecognized IgE activities that affect arterial cell biology and likely other IgE-associated pathologies in human diseases.
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Affiliation(s)
- Jing Wang
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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18
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Plihtari R, Kovanen PT, Öörni K. Acidity increases the uptake of native LDL by human monocyte-derived macrophages. Atherosclerosis 2011; 217:401-6. [DOI: 10.1016/j.atherosclerosis.2011.04.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 12/11/2022]
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19
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Jayaraman S, Gantz DL, Gursky O. Effects of phospholipase A(2) and its products on structural stability of human LDL: relevance to formation of LDL-derived lipid droplets. J Lipid Res 2011; 52:549-57. [PMID: 21220788 DOI: 10.1194/jlr.m012567] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hydrolysis and oxidation of LDL stimulate LDL entrapment in the arterial wall and promote inflammation and atherosclerosis via various mechanisms including lipoprotein fusion and lipid droplet formation. To determine the effects of FFA on these transitions, we hydrolyzed LDL by phospholipase A(2) (PLA(2)), removed FFA by albumin, and analyzed structural stability of the modified lipoproteins. Earlier, we showed that heating induces LDL remodeling, rupture, and coalescence into lipid droplets resembling those found in atherosclerotic lesions. Here, we report how FFA affect these transitions. Circular dichroism showed that mild LDL lipolysis induces partial β-sheet unfolding in apolipoprotein B. Electron microscopy, turbidity, and differential scanning calorimetry showed that mild lipolysis promotes LDL coalescence into lipid droplets. FFA removal by albumin restores LDL stability but not the protein conformation. Consequently, FFA enhance LDL coalescence into lipid droplets. Similar effects of FFA were observed in minimally oxidized LDL, in LDL enriched with exogenous FFA, and in HDL and VLDL. Our results imply that FFA promote lipoprotein coalescence into lipid droplets and explain why LDL oxidation enhances such coalescence in vivo but hampers it in vitro. Such lipid droplet formation potentially contributes to the pro-atherogenic effects of FFA.
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Affiliation(s)
- Shobini Jayaraman
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA.
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20
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Rosenson RS. Phospholipase A2 inhibition and atherosclerotic vascular disease: prospects for targeting secretory and lipoprotein-associated phospholipase A2 enzymes. Curr Opin Lipidol 2010; 21:473-80. [PMID: 20739882 DOI: 10.1097/mol.0b013e32833eb581] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Selective inhibitors of secretory phospholipase A2 and lipoprotein-associated phospholipase A2 are potential candidates for reducing recurrent cardiovascular events in patients with established coronary heart disease (CHD). With the active enrollment of CHD patients into phase III clinical trials with both classes of inhibitors, this article reviews the available experimental animal and human trial evidence that provides the rationale for the development of the phospholipase A2 inhibitors varespladib methyl and darapladib as preventive therapy. RECENT FINDINGS Recently completed experimental animal studies, human biomarker data, and vascular imaging studies provide support for proceeding with clinical outcome trials secretory phospholipase A2 and lipoprotein-associated phospholipase A2 inhibition. SUMMARY Both secretory phospholipase A2 and lipoprotein-associated phospholipase A2 inhibitors hold promise for the reduction of recurrent cardiovascular events in patients treated with current standards of care. The completion of the ongoing clinical event trials has the potential to provide a new dimension to secondary preventive therapy.
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Würtz P, Soininen P, Kangas AJ, Mäkinen VP, Groop PH, Savolainen MJ, Juonala M, Viikari JS, Kähönen M, Lehtimäki T, Raitakari OT, Ala-Korpela M. Characterization of systemic metabolic phenotypes associated with subclinical atherosclerosis. MOLECULAR BIOSYSTEMS 2010; 7:385-93. [PMID: 21057674 DOI: 10.1039/c0mb00066c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Detailed molecular phenotyping gives insight into disease mechanisms and can individualize medical practice for improved risk assessment and treatment. We show in an epidemiological study (n = 4309) that the multi-metabolic profiles obtained by serum NMR metabonomics inherently associate with the extent of atherosclerosis already in preclinical stages. Data-driven analysis of the spectral profiles of healthy, young adults revealed three distinct metabolic phenotypes associated with high carotid intima-media thickness (IMT), a surrogate marker of cardiovascular disease. The phenotypes were characterized by varying combinations of well-known metabolic disturbances like elevated VLDL and LDL and low HDL levels. Low IMT was also associated with distinct metabolic phenotypes with lipoprotein as well as other biochemical characteristics partly opposing those found for the high IMT phenotypes. Profiles of low-molecular-weight metabolites quantified from the experimentation were also characteristic for the metabolic phenotypes and substantiate developments toward the use of multi-metabolic risk phenotypes. The methodology can be taken as a direct extension for the routine analytics used for the risk assessment of atherosclerosis; quantification of metabolites will complement and might even replace conventional lipid measurements. Serum NMR metabonomics is therefore anticipated as a rational option for comprehensive cardiovascular risk assessment.
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Affiliation(s)
- Peter Würtz
- Computational Medicine Research Group, Institute of Clinical Medicine, University of Oulu and Biocenter Oulu, PO Box 5000, FI-90014, Oulu, Finland
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Lähdesmäki K, Ollila OS, Koivuniemi A, Kovanen PT, Hyvönen MT. Membrane simulations mimicking acidic pH reveal increased thickness and negative curvature in a bilayer consisting of lysophosphatidylcholines and free fatty acids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:938-46. [DOI: 10.1016/j.bbamem.2010.01.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 12/18/2009] [Accepted: 01/22/2010] [Indexed: 12/18/2022]
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23
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Karakas M, Koenig W. Phospholipase A2 as a therapeutic target for atherosclerosis. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/clp.09.74] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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