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Kızıltunç E, Gökalp S, Biberoğlu G, Yalçın Y, Cihan B, Öktem RM, İnci A, Tümer L, Yalçın MR, Abacı A. Is lysosomal acid lipase activity associated with the presence and severity of coronary artery disease? Herz 2024; 49:75-80. [PMID: 37528297 DOI: 10.1007/s00059-023-05200-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 06/18/2023] [Accepted: 06/19/2023] [Indexed: 08/03/2023]
Abstract
BACKGROUND Lipid metabolism is considerably complex and there can be many critical steps in atherogenesis. The association between lysosomal acid lipase (LAL) activity and coronary artery disease (CAD) has not been elucidated in detail. We aimed to evaluate the association between LAL activity with the presence and severity of CAD in patients who are seen in daily clinical practice. METHODS Patients who underwent coronary angiography were divided into groups according to the angiography results. Syntax scores and Gensini scores were calculated. The LAL activity was measured from dried blood spots. RESULTS Median LAL activity values were similar in all study groups (normal coronary arteries: 0.40 nmol/punch/h; non-obstructive CAD: 0.44 nmol/punch/h; obstructive chronic CAD: 0.40 nmol/punch/h; obstructive acute coronary syndrome: 0.48 nmol/punch/h) and there was no correlation between coronary atherosclerotic burden and LAL activity (correlation coefficients Syntax score and LAL: -0.032; Gensini score and LAL: -0.030). In addition, no relationship between serum lipid levels and LAL activity was detected. CONCLUSION The presence of CAD and its severity is not associated with the LAL activity in patients encountered in daily clinical practice.
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Affiliation(s)
- Emrullah Kızıltunç
- Department of Cardiology. Emniyet, Gazi University School of Medicine, 06560, Ankara, Yenimahalle, Turkey.
| | - Sabire Gökalp
- Department of Pediatric Metabolism and Nutrition, Gazi University School of Medicine, Ankara, Turkey
| | - Gürsel Biberoğlu
- Department of Pediatric Metabolism and Nutrition, Gazi University School of Medicine, Ankara, Turkey
| | - Yakup Yalçın
- Department of Cardiology. Emniyet, Gazi University School of Medicine, 06560, Ankara, Yenimahalle, Turkey
| | - Burcu Cihan
- Department of Cardiology. Emniyet, Gazi University School of Medicine, 06560, Ankara, Yenimahalle, Turkey
| | - Rıdvan M Öktem
- Department of Pediatric Metabolism and Nutrition, Gazi University School of Medicine, Ankara, Turkey
| | - Aslı İnci
- Department of Pediatric Metabolism and Nutrition, Gazi University School of Medicine, Ankara, Turkey
| | - Leyla Tümer
- Department of Pediatric Metabolism and Nutrition, Gazi University School of Medicine, Ankara, Turkey
| | - Mehmet R Yalçın
- Department of Cardiology. Emniyet, Gazi University School of Medicine, 06560, Ankara, Yenimahalle, Turkey
| | - Adnan Abacı
- Department of Cardiology. Emniyet, Gazi University School of Medicine, 06560, Ankara, Yenimahalle, Turkey
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Korbelius M, Kuentzel KB, Bradić I, Vujić N, Kratky D. Recent insights into lysosomal acid lipase deficiency. Trends Mol Med 2023; 29:425-438. [PMID: 37028992 DOI: 10.1016/j.molmed.2023.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/14/2023] [Accepted: 03/14/2023] [Indexed: 04/09/2023]
Abstract
Lysosomal acid lipase (LAL) is the sole enzyme known to degrade neutral lipids in the lysosome. Mutations in the LAL-encoding LIPA gene lead to rare lysosomal lipid storage disorders with complete or partial absence of LAL activity. This review discusses the consequences of defective LAL-mediated lipid hydrolysis on cellular lipid homeostasis, epidemiology, and clinical presentation. Early detection of LAL deficiency (LAL-D) is essential for disease management and survival. LAL-D must be considered in patients with dyslipidemia and elevated aminotransferase concentrations of unknown etiology. Enzyme replacement therapy, sometimes in combination with hematopoietic stem cell transplantation (HSCT), is currently the only therapy for LAL-D. New technologies based on mRNA and viral vector gene transfer are recent efforts to provide other effective therapeutic strategies.
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Affiliation(s)
- Melanie Korbelius
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Katharina B Kuentzel
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Ivan Bradić
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Nemanja Vujić
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria.
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3
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Besler KJ, Blanchard V, Francis GA. Lysosomal acid lipase deficiency: A rare inherited dyslipidemia but potential ubiquitous factor in the development of atherosclerosis and fatty liver disease. Front Genet 2022; 13:1013266. [PMID: 36204319 PMCID: PMC9530988 DOI: 10.3389/fgene.2022.1013266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 09/06/2022] [Indexed: 11/13/2022] Open
Abstract
Lysosomal acid lipase (LAL), encoded by the gene LIPA, is the sole neutral lipid hydrolase in lysosomes, responsible for cleavage of cholesteryl esters and triglycerides into their component parts. Inherited forms of complete (Wolman Disease, WD) or partial LAL deficiency (cholesteryl ester storage disease, CESD) are fortunately rare. Recently, LAL has been identified as a cardiovascular risk gene in genome-wide association studies, though the directionality of risk conferred remains controversial. It has also been proposed that the low expression and activity of LAL in arterial smooth muscle cells (SMCs) that occurs inherently in nature is a likely determinant of the propensity of SMCs to form the majority of foam cells in atherosclerotic plaque. LAL also likely plays a potential role in fatty liver disease. This review highlights the nature of LAL gene mutations in WD and CESD, the association of LAL with prediction of cardiovascular risk from genome-wide association studies, the importance of relative LAL deficiency in SMC foam cells, and the need to further interrogate the pathophysiological impact and cell type-specific role of enhancing LAL activity as a novel treatment strategy to reduce the development and induce the regression of ischemic cardiovascular disease and fatty liver.
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Ozuynuk AS, Erkan AF, Ekici B, Erginel-Unaltuna N, Coban N. Cholesterol-related gene variants are associated with diabetes in coronary artery disease patients. Mol Biol Rep 2021; 48:3945-3954. [PMID: 34021444 DOI: 10.1007/s11033-021-06393-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/29/2021] [Indexed: 11/27/2022]
Abstract
Coronary artery disease (CAD) which is a complex cardiovascular disease is the leading cause of death worldwide. The changing prevalence of the disease in different ethnic groups pointing out the genetic background of CAD. In this study, we aimed to evaluate the contribution of selected cholesterol metabolism-related gene polymorphisms to CAD presence. A total of 493 individuals who underwent coronary angiography were divided into 2 groups: normal coronary arteries (≤ 30% stenosis) and critical disease (≥ 50% stenosis). Individuals were genotyped for APOC1 (rs11568822), APOD (rs1568565), LIPA (rs13500), SORL1 (rs2282649), and LDLR (rs5930) polymorphisms using hydrolysis probes in Real-Time PCR. Blood samples were drawn before coronary angiography and biochemical analyses were done. The results were statistically evaluated. When the study group was stratified according to CAD, the minor allele of APOD polymorphism was found related to decreased risk for T2DM in the non-CAD group. In logistic regression analysis adjusted for several confounders, LDLR rs5930 polymorphism was found associated with T2DM presence in the male CAD group [OR = 0.502, 95%CI (0.259-0.974), p = 0.042]. Besides, APOD and LIPA polymorphisms were shown to affect serum lipid levels in non-CAD T2DM patients (p < 0.05). The minor allele of APOC1 was found associated with triglyceride levels in males independent of CAD status. Besides, LDLR minor allele carrier females had elevated HbA1c and glucose levels independent from CAD status in the whole group. The cholesterol metabolism-related gene polymorphisms were found associated with T2DM and biochemical parameters stratified to sex, CAD, and T2DM status.
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Affiliation(s)
- Aybike Sena Ozuynuk
- Department of Genetics, Istanbul University, Aziz Sancar Institute for Experimental Medicine, Sehremini, Istanbul, 34080, Turkey
- Graduate School of Health Sciences, Istanbul University, Istanbul, Turkey
| | - Aycan Fahri Erkan
- Faculty of Medicine, Department of Cardiology, Ufuk University, Ankara, Turkey
| | - Berkay Ekici
- Faculty of Medicine, Department of Cardiology, Ufuk University, Ankara, Turkey
| | - Nihan Erginel-Unaltuna
- Department of Genetics, Istanbul University, Aziz Sancar Institute for Experimental Medicine, Sehremini, Istanbul, 34080, Turkey
| | - Neslihan Coban
- Department of Genetics, Istanbul University, Aziz Sancar Institute for Experimental Medicine, Sehremini, Istanbul, 34080, Turkey.
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Dubland JA, Allahverdian S, Besler KJ, Ortega C, Wang Y, Pryma CS, Boukais K, Chan T, Seidman MA, Francis GA. Low LAL (Lysosomal Acid Lipase) Expression by Smooth Muscle Cells Relative to Macrophages as a Mechanism for Arterial Foam Cell Formation. Arterioscler Thromb Vasc Biol 2021; 41:e354-e368. [PMID: 33792344 DOI: 10.1161/atvbaha.120.316063] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Joshua A Dubland
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Sima Allahverdian
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Katrina J Besler
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Carleena Ortega
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Ying Wang
- Pathology and Laboratory Medicine (Y.W.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Collin S Pryma
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Kamel Boukais
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Teddy Chan
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Michael A Seidman
- Laboratory Medicine and Pathobiology, University of Toronto, Canada (M.A.S.)
| | - Gordon A Francis
- Departments of Medicine (J.A.D., S.A., K.J.B., C.O., C.S.P., K.B., T.C., G.A.F.), Centre for Heart Lung Innovation, Providence Healthcare Research Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
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Marques ARA, Ramos C, Machado-Oliveira G, Vieira OV. Lysosome (Dys)function in Atherosclerosis-A Big Weight on the Shoulders of a Small Organelle. Front Cell Dev Biol 2021; 9:658995. [PMID: 33855029 PMCID: PMC8039146 DOI: 10.3389/fcell.2021.658995] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/11/2021] [Indexed: 12/15/2022] Open
Abstract
Atherosclerosis is a progressive insidious chronic disease that underlies most of the cardiovascular pathologies, including myocardial infarction and ischemic stroke. The malfunctioning of the lysosomal compartment has a central role in the etiology and pathogenesis of atherosclerosis. Lysosomes are the degradative organelles of mammalian cells and process endogenous and exogenous substrates in a very efficient manner. Dysfunction of these organelles and consequent inefficient degradation of modified low-density lipoproteins (LDL) and apoptotic cells in atherosclerotic lesions have, therefore, numerous deleterious consequences for cellular homeostasis and disease progression. Lysosome dysfunction has been mostly studied in the context of the inherited lysosomal storage disorders (LSDs). However, over the last years it has become increasingly evident that the consequences of this phenomenon are more far-reaching, also influencing the progression of multiple acquired human pathologies, such as neurodegenerative diseases, cancer, and cardiovascular diseases (CVDs). During the formation of atherosclerotic plaques, the lysosomal compartment of the various cells constituting the arterial wall is under severe stress, due to the tremendous amounts of lipoproteins being processed by these cells. The uncontrolled uptake of modified lipoproteins by arterial phagocytic cells, namely macrophages and vascular smooth muscle cells (VSMCs), is the initial step that triggers the pathogenic cascade culminating in the formation of atheroma. These cells become pathogenic "foam cells," which are characterized by dysfunctional lipid-laden lysosomes. Here, we summarize the current knowledge regarding the origin and impact of the malfunctioning of the lysosomal compartment in plaque cells. We further analyze how the field of LSD research may contribute with some insights to the study of CVDs, particularly how therapeutic approaches that target the lysosomes in LSDs could be applied to hamper atherosclerosis progression and associated mortality.
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Affiliation(s)
- André R A Marques
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Cristiano Ramos
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Gisela Machado-Oliveira
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Otília V Vieira
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
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Trivedi PC, Bartlett JJ, Pulinilkunnil T. Lysosomal Biology and Function: Modern View of Cellular Debris Bin. Cells 2020; 9:cells9051131. [PMID: 32375321 PMCID: PMC7290337 DOI: 10.3390/cells9051131] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 02/07/2023] Open
Abstract
Lysosomes are the main proteolytic compartments of mammalian cells comprising of a battery of hydrolases. Lysosomes dispose and recycle extracellular or intracellular macromolecules by fusing with endosomes or autophagosomes through specific waste clearance processes such as chaperone-mediated autophagy or microautophagy. The proteolytic end product is transported out of lysosomes via transporters or vesicular membrane trafficking. Recent studies have demonstrated lysosomes as a signaling node which sense, adapt and respond to changes in substrate metabolism to maintain cellular function. Lysosomal dysfunction not only influence pathways mediating membrane trafficking that culminate in the lysosome but also govern metabolic and signaling processes regulating protein sorting and targeting. In this review, we describe the current knowledge of lysosome in influencing sorting and nutrient signaling. We further present a mechanistic overview of intra-lysosomal processes, along with extra-lysosomal processes, governing lysosomal fusion and fission, exocytosis, positioning and membrane contact site formation. This review compiles existing knowledge in the field of lysosomal biology by describing various lysosomal events necessary to maintain cellular homeostasis facilitating development of therapies maintaining lysosomal function.
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Affiliation(s)
- Purvi C. Trivedi
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4H7, Canada; (P.C.T.); (J.J.B.)
- Dalhousie Medicine New Brunswick, Saint John, NB E2L 4L5, Canada
| | - Jordan J. Bartlett
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4H7, Canada; (P.C.T.); (J.J.B.)
- Dalhousie Medicine New Brunswick, Saint John, NB E2L 4L5, Canada
| | - Thomas Pulinilkunnil
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4H7, Canada; (P.C.T.); (J.J.B.)
- Dalhousie Medicine New Brunswick, Saint John, NB E2L 4L5, Canada
- Correspondence: ; Tel.: +1-(506)-636-6973
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Abstract
Lysosomal acid lipase (LAL), encoded by the lipase A ( LIPA) gene, hydrolyzes cholesteryl esters and triglycerides to generate free fatty acids and cholesterol in the cell. The essential role of LAL in lipid metabolism has been confirmed in mice and human with LAL deficiency. In humans, loss-of-function mutations of LIPA cause rare lysosomal disorders, Wolman disease and cholesteryl ester storage disease, in which LAL enzyme-replacement therapy has shown significant benefits in a phase 3 clinical trial. Recent studies have revealed the regulatory role of lipolytic products of lysosomal lipid hydrolysis in catabolic, anabolic, and signaling pathways. In vivo studies in mice with knockout of Lipa highlight the systemic impact of Lipa deficiency on metabolic homeostasis and immune cell function. Genome-wide association studies and functional genomic studies have identified LIPA as a risk locus for coronary heart disease, but the causal variants and mechanisms remain to be determined. Future studies will continue to focus on the role of LAL in the crosstalk between lipid metabolism and cellular function in health and diseases including coronary heart disease.
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Affiliation(s)
- Fang Li
- From the Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York
| | - Hanrui Zhang
- From the Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York
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Wang D, Yang Y, Lei Y, Tzvetkov NT, Liu X, Yeung AWK, Xu S, Atanasov AG. Targeting Foam Cell Formation in Atherosclerosis: Therapeutic Potential of Natural Products. Pharmacol Rev 2019; 71:596-670. [PMID: 31554644 DOI: 10.1124/pr.118.017178] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Foam cell formation and further accumulation in the subendothelial space of the vascular wall is a hallmark of atherosclerotic lesions. Targeting foam cell formation in the atherosclerotic lesions can be a promising approach to treat and prevent atherosclerosis. The formation of foam cells is determined by the balanced effects of three major interrelated biologic processes, including lipid uptake, cholesterol esterification, and cholesterol efflux. Natural products are a promising source for new lead structures. Multiple natural products and pharmaceutical agents can inhibit foam cell formation and thus exhibit antiatherosclerotic capacity by suppressing lipid uptake, cholesterol esterification, and/or promoting cholesterol ester hydrolysis and cholesterol efflux. This review summarizes recent findings on these three biologic processes and natural products with demonstrated potential to target such processes. Discussed also are potential future directions for studying the mechanisms of foam cell formation and the development of foam cell-targeted therapeutic strategies.
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Affiliation(s)
- Dongdong Wang
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Yang Yang
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Yingnan Lei
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Nikolay T Tzvetkov
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Xingde Liu
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Andy Wai Kan Yeung
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Suowen Xu
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Atanas G Atanasov
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
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Baratta F, Pastori D, Tozzi G, D'Erasmo L, Di Costanzo A, Arca M, Ettorre E, Ginanni Corradini S, Violi F, Angelico F, Del Ben M. Lysosomal acid lipase activity and liver fibrosis in the clinical continuum of non-alcoholic fatty liver disease. Liver Int 2019; 39:2301-2308. [PMID: 31392821 DOI: 10.1111/liv.14206] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/15/2019] [Accepted: 07/26/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND AIMS Recent evidence showed a reduced activity of the lysosomal acid lipase (LAL) in patients with non-alcoholic fatty liver disease (NAFLD) and cryptogenic cirrhosis (CC). However, the relationship between LAL activity and liver fibrosis has never been investigated. METHODS Cross-sectional study including 575 outpatients referred for the management of cardio-metabolic and liver disease. The absence of liver fibrosis was defined by a FIB-4 < 1.30 and NAFLD fibrosis score (NFS) <-1.455. LAL activity was measured with dried blood spot technique. RESULTS Overall, 515 patients had a diagnosis of NAFLD (454 NAFL and 61 biopsy-proven NASH) and 60 of CC. The value of LAL activity progressively decreased from healthy subjects to NAFL/NASH patients to CC (P < .001). LAL activity was reduced by 10% in patients with NAFL, by 20% in NASH and by 50% in CC. The prevalence of CC decreased across the tertiles of LAL activity: 22.2% in the lowest, 4.6% in the intermediate and 0.5% in the highest tertile. In NAFLD patients, 69.9% had a FIB4 < 1.30, and 43.1% a NFS <-1.455. Multivariate logistic regression analysis showed that Log (LAL activity) was associated with FIB-4 < 1.30 (Odds ratio [OR] 2.19 95% confidence interval [CI] 1.33-3.62, P = .002) and NFS < -1.455 (OR 2.43, 95% CI 1.51-3.91, P < .001) after adjustment for confounding factors. CONCLUSIONS We found a progressive reduction of LAL activity according to liver disease severity. LAL activity was inversely associated with markers of liver fibrosis in patients with NAFLD.
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Affiliation(s)
- Francesco Baratta
- I Clinica Medica, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy.,Department of Anatomical Sciences, Histological, Legal Medical and Locomotor, Sapienza University of Rome, Rome, Italy
| | - Daniele Pastori
- I Clinica Medica, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Giulia Tozzi
- Hepatology, Gastroenterology and Nutrition Unit, IRCCS "Bambino Gesù" Children's Hospital, Rome, Italy
| | - Laura D'Erasmo
- I Clinica Medica, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Alessia Di Costanzo
- I Clinica Medica, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Marcello Arca
- I Clinica Medica, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Evaristo Ettorre
- Division of Gerontology, Department of Cardiovascular, Respiratory, Nephrologic, Anesthesiologic and Geriatric Sciences, Sapienza University, Rome, Italy
| | | | - Francesco Violi
- I Clinica Medica, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy.,Mediterranea Cardiocentro, Naples, Italy
| | - Francesco Angelico
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Maria Del Ben
- I Clinica Medica, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
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11
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Gomaraschi M, Bonacina F, Norata GD. Lysosomal Acid Lipase: From Cellular Lipid Handler to Immunometabolic Target. Trends Pharmacol Sci 2019; 40:104-115. [PMID: 30665623 DOI: 10.1016/j.tips.2018.12.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 01/28/2023]
Abstract
Lysosomal acid lipase (LAL) hydrolyzes cholesteryl esters (CEs) and triglycerides (TGs) to free cholesterol (FC) and free fatty acids (FFAs), which are then used for metabolic purposes in the cell. The process also occurs in immune cells that adapt their metabolic machinery to cope with the different energetic requirements associated with cell activation, proliferation, and polarization. LAL deficiency (LALD) causes severe lipid accumulation and affects the immunometabolic signature in animal models. In humans, LAL deficiency is associated with a peculiar clinical immune phenotype, secondary hemophagocytic lymphohistiocytosis. These observations suggest that LAL might play an important role in cellular immunometabolic modulation, and availability of an effective enzyme replacement strategy makes LAL an attractive target to rewire the metabolic machinery of immune cells beyond its role in controlling cellular lipid metabolism.
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Affiliation(s)
- M Gomaraschi
- Center E. Grossi Paoletti, Department of Excellence of Pharmacological and Biomolecular Sciences (DisFeB), Università Degli Studi di Milano, Milan 20133, Italy
| | - F Bonacina
- Department of Excellence of Pharmacological and Biomolecular Sciences (DisFeB), Università Degli Studi di Milano, Milan 20133, Italy
| | - G D Norata
- Department of Excellence of Pharmacological and Biomolecular Sciences (DisFeB), Università Degli Studi di Milano, Milan 20133, Italy; SISA Centre, Bassini Hospital, Cinisello Balsamo, 20092, Italy.
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12
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Ruuth M, Soronen J, Kaiharju E, Merikanto K, Perttilä J, Metso J, Lee-Rueckert M, Taskinen MR, Kovanen PT, Öörni K, Olkkonen VM, Jauhiainen MS, Laurila PP. USF1 deficiency alleviates inflammation, enhances cholesterol efflux and prevents cholesterol accumulation in macrophages. Lipids Health Dis 2018; 17:285. [PMID: 30545366 PMCID: PMC6293625 DOI: 10.1186/s12944-018-0930-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/26/2018] [Indexed: 12/23/2022] Open
Abstract
Background The focus of studies on high-density lipoproteins (HDL) has shifted from HDL-cholesterol (HDL-C) to HDL function. We recently demonstrated that low USF1 expression in mice and humans associates with high plasma HDL-C and low triglyceride levels, as well as protection against obesity, insulin resistance, and atherosclerosis. Here, we studied the impact of USF1 deficiency on HDL functional capacity and macrophage atherogenic functions, including inflammation, cholesterol efflux, and cholesterol accumulation. Methods We used a congenic Usf1 deficient mice in C57Bl/6JRccHsd background and blood samples were collected to isolate HDL for structural and functional studies. Lentiviral preparations containing the USF1 silencing shRNA expression vector were used to silence USF1 in human THP-1 and Huh-7 cells. Cholesterol efflux from acetyl-LDL loaded THP-1 macrophages was measured using HDL and plasma as acceptors. Gene expression analysis from USF1 silenced peritoneal macrophages was carried out using Affymetrix protocols. Results We show that Usf1 deficiency not only increases HDL-C levels in vivo, consistent with elevated ABCA1 protein expression in hepatic cell lines, but also improves the functional capacity of HDL particles. HDL particles derived from Usf1 deficient mice remove cholesterol more efficiently from macrophages, attributed to their higher contents of phospholipids. Furthermore, silencing of USF1 in macrophages enhanced the cholesterol efflux capacity of these cells. These findings are consistent with reduced inflammatory burden of USF1 deficient macrophages, manifested by reduced secretion of pro-inflammatory cytokines MCP-1 and IL-1β and protection against inflammation-induced macrophage cholesterol accumulation in a cell-autonomous manner. Conclusions Our findings identify USF1 as a novel factor regulating HDL functionality, showing that USF1 inactivation boosts cholesterol efflux, reduces macrophage inflammation and attenuates macrophage cholesterol accumulation, linking improved macrophage cholesterol metabolism and inflammatory pathways to the antiatherogenic function of USF1 deficiency.
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Affiliation(s)
- Maija Ruuth
- Wihuri Research Institute, FI-00290, Helsinki, Finland.,Research Program Unit, University of Helsinki, FI-00014, Helsinki, Finland
| | - Jarkko Soronen
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, FI-00251, Helsinki, Finland.,Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Essi Kaiharju
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, FI-00251, Helsinki, Finland
| | - Krista Merikanto
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, FI-00251, Helsinki, Finland
| | - Julia Perttilä
- Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Jari Metso
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, FI-00251, Helsinki, Finland
| | | | - Marja-Riitta Taskinen
- Diabetes and Obesity Research Program, University of Helsinki, FI-00014, Helsinki, Finland
| | | | | | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290, Helsinki, Finland.,Department of Anatomy, Faculty of Medicine, University of Helsinki, FI-00014, Helsinki, Finland
| | - Matti S Jauhiainen
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, FI-00251, Helsinki, Finland. .,Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290, Helsinki, Finland.
| | - Pirkka-Pekka Laurila
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, FI-00251, Helsinki, Finland.,Department of Medical and Clinical Genetics, University of Helsinki, FI-00014, Helsinki, Finland.,Institute for Molecular Medicine Finland, FIMM, FI-00251, Helsinki, Finland
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13
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Yu XH, Zhang DW, Zheng XL, Tang CK. Cholesterol transport system: An integrated cholesterol transport model involved in atherosclerosis. Prog Lipid Res 2018; 73:65-91. [PMID: 30528667 DOI: 10.1016/j.plipres.2018.12.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/30/2018] [Accepted: 12/01/2018] [Indexed: 02/07/2023]
Abstract
Atherosclerosis, the pathological basis of most cardiovascular disease (CVD), is closely associated with cholesterol accumulation in the arterial intima. Excessive cholesterol is removed by the reverse cholesterol transport (RCT) pathway, representing a major antiatherogenic mechanism. In addition to the RCT, other pathways are required for maintaining the whole-body cholesterol homeostasis. Thus, we propose a working model of integrated cholesterol transport, termed the cholesterol transport system (CTS), to describe body cholesterol metabolism. The novel model not only involves the classical view of RCT but also contains other steps, such as cholesterol absorption in the small intestine, low-density lipoprotein uptake by the liver, and transintestinal cholesterol excretion. Extensive studies have shown that dysfunctional CTS is one of the major causes for hypercholesterolemia and atherosclerosis. Currently, several drugs are available to improve the CTS efficiently. There are also several therapeutic approaches that have entered into clinical trials and shown considerable promise for decreasing the risk of CVD. In recent years, a variety of novel findings reveal the molecular mechanisms for the CTS and its role in the development of atherosclerosis, thereby providing novel insights into the understanding of whole-body cholesterol transport and metabolism. In this review, we summarize the latest advances in this area with an emphasis on the therapeutic potential of targeting the CTS in CVD patients.
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Affiliation(s)
- Xiao-Hua Yu
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical Research Experiment Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China
| | - Da-Wei Zhang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada
| | - Xi-Long Zheng
- Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Health Sciences Center, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Chao-Ke Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical Research Experiment Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China.
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14
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Abstract
PURPOSE OF REVIEW Lysosomal acid lipase (LAL), encoded by the LIPA gene, is an essential lysosomal enzyme that hydrolyzes cholesteryl ester and triglyceride delivered to the lysosome. This review highlights the novel pathophysiological role of LAL, the functional genomic discoveries of LIPA as a risk locus for coronary heart diseases (CHD), and the clinical advance in therapies for LAL deficiency. RECENT FINDINGS The essential role of LAL in lipid metabolism has been confirmed in human and mice with LAL deficiency. In humans, loss-of-function mutations of LIPA cause rare lysosomal disorders, Wolman disease, and cholesteryl ester storage disease, in which LAL enzyme replacement therapy has shown significant benefits in a phase 3 clinical trial. Recent studies have revealed the role of LAL-mediated lysosomal lipolysis in regulating macrophage M2 polarization, lipid mediator production, VLDL secretion, lysosomal function and autophagy, extracellular degradation of aggregated-LDL, and adipose tissue lipolysis. Genome-wide association studies and functional genomic studies have identified LIPA as a risk locus for CHD, but the causal variants and mechanisms remain to be determined. SUMMARY Despite years of research, our understanding of LAL is incomplete. Future studies will continue to focus on the key pathophysiological functions of LAL in health and diseases including CHD.
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Affiliation(s)
- Hanrui Zhang
- Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, New York, USA
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15
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Bowden KL, Dubland JA, Chan T, Xu YH, Grabowski GA, Du H, Francis GA. LAL (Lysosomal Acid Lipase) Promotes Reverse Cholesterol Transport In Vitro and In Vivo. Arterioscler Thromb Vasc Biol 2018; 38:1191-1201. [PMID: 29599133 DOI: 10.1161/atvbaha.117.310507] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 03/13/2018] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To explore the role of LAL (lysosomal acid lipase) in macrophage cholesterol efflux and whole-body reverse cholesterol transport. APPROACH AND RESULTS Immortalized peritoneal macrophages from lal-/- mice showed reduced expression of ABCA1 (ATP-binding cassette transporter A1) and ABCG1 (ATP-binding cassette transporter G1), reduced production of the regulatory oxysterol 27-hydroxycholesterol, and impaired suppression of cholesterol synthesis on exposure to acetylated low-density lipoprotein when compared with lal+/+ macrophages. LAL-deficient mice also showed reduced hepatic ABCG5 (ATP-binding cassette transporter G5) and ABCG8 (ATP-binding cassette transporter G8) expression compared with lal+/+ mice. LAL-deficient macrophages loaded with [3H]-cholesteryl oleate-labeled acetylated low-density lipoprotein showed impaired efflux of released [3H]-cholesterol to apoA-I (apolipoprotein A-I), with normalization of [3H]-cholesteryl ester levels and partial correction of ABCA1 expression and cholesterol efflux to apoA-I when treated with exogenous rhLAL (recombinant human LAL protein). LAL-deficient mice injected intraperitoneally with lal-/- macrophages cholesterol loaded and labeled in the same way exhibited only 1.55±0.35% total injected [3H]-cholesterol counts appearing in the feces for 48 h (n=30), compared with 5.38±0.92% in lal+/+ mice injected with labeled lal+/+ macrophages (n=27), P<0.001. To mimic the therapeutic condition of delivery of supplemental LAL in vivo, injection of labeled lal-/- macrophages into lal+/+ mice resulted in a significant increase in reverse cholesterol transport (2.60±0.46% of 3H-cholesterol counts in feces at 48 hours [n=19]; P<0.001 when compared with injection into lal-/- mice). CONCLUSIONS These results indicate a critical role for LAL in promoting both macrophage and whole-body reverse cholesterol transport and the ability of supplemental LAL to be taken up and correct reverse cholesterol transport in vivo.
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Affiliation(s)
- Kristin L Bowden
- From the Department of Medicine, Centre for Heart Lung Innovation, Institute for Heart + Lung Health, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia, Vancouver, Canada (K.L.B., J.A.D., T.C., G.A.F.)
| | - Joshua A Dubland
- From the Department of Medicine, Centre for Heart Lung Innovation, Institute for Heart + Lung Health, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia, Vancouver, Canada (K.L.B., J.A.D., T.C., G.A.F.)
| | - Teddy Chan
- From the Department of Medicine, Centre for Heart Lung Innovation, Institute for Heart + Lung Health, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia, Vancouver, Canada (K.L.B., J.A.D., T.C., G.A.F.)
| | - You-Hai Xu
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, OH (Y.-H.X., G.A.G.).,Division of Human Genetics, Cincinnati Children's Hospital Medical Center, OH (Y.-H.X., G.A.G.)
| | - Gregory A Grabowski
- From the Department of Medicine, Centre for Heart Lung Innovation, Institute for Heart + Lung Health, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia, Vancouver, Canada (K.L.B., J.A.D., T.C., G.A.F.).,Division of Human Genetics, Cincinnati Children's Hospital Medical Center, OH (Y.-H.X., G.A.G.).,Department of Pediatrics, University of Cincinnati College of Medicine, OH (Y.-H.X., G.A.G.)
| | - Hong Du
- Department of Pathology and Laboratory Medicine, Indiana University, Indianapolis (H.D.)
| | - Gordon A Francis
- From the Department of Medicine, Centre for Heart Lung Innovation, Institute for Heart + Lung Health, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia, Vancouver, Canada (K.L.B., J.A.D., T.C., G.A.F.)
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16
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Abstract
Lysosomal acid lipase deficiency (LAL-D) is a rare, life-threatening, autosomal recessive, lysosomal storage disease caused by mutations in the LIPA gene, which encodes for lysosomal acid lipase (LAL). This enzyme is necessary for the hydrolysis of cholesteryl ester and triglyceride in lysosomes. Deficient LAL activity causes accumulation of these lipids in lysosomes and a marked decrease in the cytoplasmic free cholesterol concentration, leading to dysfunctional cholesterol homeostasis. The accumulation of neutral lipid occurs predominantly in liver, spleen, and macrophages throughout the body, and the aberrant cholesterol homeostasis causes a marked dyslipidemia. LAL-D is characterized by accelerated atherosclerotic cardiovascular disease (ASCVD) and hepatic microvesicular or mixed steatosis, leading to inflammation, fibrosis, cirrhosis and liver failure. LAL-D presents as a clinical continuum with two phenotypes: the infantile-onset phenotype, formally referred to as Wolman disease, and the later-onset phenotype, formerly referred to as cholesteryl ester storage disease. Infants with LAL-D present within the first few weeks of life with vomiting, diarrhea, hepatosplenomegaly, failure to thrive and rapid progression to liver failure and death by 6-12 months of age. Children and young adults with LAL-D generally present with marked dyslipidemia, hepatic enzyme elevation, hepatomegaly and mixed steatosis by liver biopsy. The average age of the initial signs and symptoms of the later-onset phenotype is about 5 years old. The typical dyslipidemia is a significantly elevated low-density lipoprotein cholesterol (LDL-C) concentration and a low high-density lipoprotein cholesterol (HDL-C) concentration, placing these individuals at heightened risk for premature ASCVD. Diagnosis of the later-onset phenotype of LAL-D requires a heightened awareness of the disease because the dyslipidemia and hepatic transaminase elevation combination are common and overlap with other metabolic disorders. LAL-D should be considered in the differential diagnosis of healthy weight children and young adults with unexplained hepatic transaminase elevation accompanied by an elevated LDL-C level (>160 mg/dL) and low HDL-C level (<35 mg/dL) that is not caused by monogenic and polygenic lipid disorders or secondary factors. Treatment of LAL-D with sebelipase alfa (LAL replacement enzyme) should be considered as the standard of treatment in all individuals diagnosed with LAL-D. Other ASCVD risk factors that may be present (hypertension, tobacco use, diabetes mellitus, etc.) should be managed appropriately, consistent with secondary prevention goals.
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Affiliation(s)
- James J Maciejko
- Division of Cardiology, St. John Hospital and Medical Center, 22101 Moross Road, Detroit, MI, 48236, USA.
- Department of Internal Medicine, Wayne State University School of Medicine, 540 East Canfield, Detroit, MI, 48201, USA.
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17
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Morris GE, Braund PS, Moore JS, Samani NJ, Codd V, Webb TR. Coronary Artery Disease-Associated LIPA Coding Variant rs1051338 Reduces Lysosomal Acid Lipase Levels and Activity in Lysosomes. Arterioscler Thromb Vasc Biol 2017; 37:1050-1057. [PMID: 28279971 PMCID: PMC5444428 DOI: 10.1161/atvbaha.116.308734] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/27/2017] [Indexed: 12/20/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— Genome-wide association studies have linked variants at chromosome 10q23 with increased coronary artery disease risk. The disease-associated variants fall in LIPA, which encodes lysosomal acid lipase (LAL), the enzyme responsible for lysosomal cholesteryl ester hydrolysis. Loss-of-function mutations in LIPA result in accelerated atherosclerosis. Surprisingly, the coronary artery disease variants are associated with increased LIPA expression in some cell types. In this study, we address this apparent contradiction. Approach and Results— We investigated a coding variant rs1051338, which is in high linkage disequilibrium (r2=0.89) with the genome-wide association study lead–associated variant rs2246833 and causes a nonsynonymous threonine to proline change within the signal peptide of LAL. Transfection of allele-specific expression constructs showed that the risk allele results in reduced lysosomal LAL protein (P=0.004) and activity (P=0.005). Investigation of LAL localization and turnover showed the risk LAL protein is degraded more quickly. This mechanism was confirmed in disease-relevant macrophages from individuals homozygous for either the nonrisk or risk allele. There was no difference in LAL protein or activity in whole macrophage extracts; however, we found reduced LAL protein (P=0.02) and activity (P=0.026) with the risk genotype in lysosomal extracts, suggesting that the risk genotype affects lysosomal LAL activity. Inhibition of the proteasome resulted in equal amounts of lysosomal LAL protein in risk and nonrisk macrophages. Conclusions— Our findings show that the coronary artery disease–associated coding variant rs1051338 causes reduced lysosomal LAL protein and activity because of increased LAL degradation, providing a plausible causal mechanism of increased coronary artery disease risk.
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Affiliation(s)
- Gavin E Morris
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Peter S Braund
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Jasbir S Moore
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Nilesh J Samani
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Veryan Codd
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom
| | - Tom R Webb
- From the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, United Kingdom.
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18
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Wasiak S, Gilham D, Tsujikawa LM, Halliday C, Norek K, Patel RG, McLure KG, Young PR, Gordon A, Kulikowski E, Johansson J, Sweeney M, Wong NC. Data on gene and protein expression changes induced by apabetalone (RVX-208) in ex vivo treated human whole blood and primary hepatocytes. Data Brief 2016; 8:1280-8. [PMID: 27570805 PMCID: PMC4990638 DOI: 10.1016/j.dib.2016.07.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 07/05/2016] [Accepted: 07/22/2016] [Indexed: 01/20/2023] Open
Abstract
Apabetalone (RVX-208) inhibits the interaction between epigenetic regulators known as bromodomain and extraterminal (BET) proteins and acetyl-lysine marks on histone tails. Data presented here supports the manuscript published in Atherosclerosis “RVX-208, a BET-inhibitor for Treating Atherosclerotic Cardiovascular Disease, Raises ApoA-I/HDL and Represses Pathways that Contribute to Cardiovascular Disease” (Gilham et al., 2016) [1]. It shows that RVX-208 and a comparator BET inhibitor (BETi) JQ1 increase mRNA expression and production of apolipoprotein A-I (ApoA-I), the main protein component of high density lipoproteins, in primary human and African green monkey hepatocytes. In addition, reported here are gene expression changes from a microarray-based analysis of human whole blood and of primary human hepatocytes treated with RVX-208.
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19
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Nurnberg ST, Zhang H, Hand NJ, Bauer RC, Saleheen D, Reilly MP, Rader DJ. From Loci to Biology: Functional Genomics of Genome-Wide Association for Coronary Disease. Circ Res 2016; 118:586-606. [PMID: 26892960 DOI: 10.1161/circresaha.115.306464] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genome-wide association studies have provided a rich collection of ≈ 58 coronary artery disease (CAD) loci that suggest the existence of previously unsuspected new biology relevant to atherosclerosis. However, these studies only identify genomic loci associated with CAD, and many questions remain even after a genomic locus is definitively implicated, including the nature of the causal variant(s) and the causal gene(s), as well as the directionality of effect. There are several tools that can be used for investigation of the functional genomics of these loci, and progress has been made on a limited number of novel CAD loci. New biology regarding atherosclerosis and CAD will be learned through the functional genomics of these loci, and the hope is that at least some of these new pathways relevant to CAD pathogenesis will yield new therapeutic targets for the prevention and treatment of CAD.
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Affiliation(s)
- Sylvia T Nurnberg
- From the Division of Translational Medicine and Human Genetics, Department of Medicine (S.T.N., R.C.B., D.J.R.), Penn Cardiovascular Institute, Department of Medicine (H.Z., M.P.R., D.J.R.), Department of Genetics (N.J.H., D.J.R.), and Department of Biostatistics and Epidemiology (D.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Hanrui Zhang
- From the Division of Translational Medicine and Human Genetics, Department of Medicine (S.T.N., R.C.B., D.J.R.), Penn Cardiovascular Institute, Department of Medicine (H.Z., M.P.R., D.J.R.), Department of Genetics (N.J.H., D.J.R.), and Department of Biostatistics and Epidemiology (D.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Nicholas J Hand
- From the Division of Translational Medicine and Human Genetics, Department of Medicine (S.T.N., R.C.B., D.J.R.), Penn Cardiovascular Institute, Department of Medicine (H.Z., M.P.R., D.J.R.), Department of Genetics (N.J.H., D.J.R.), and Department of Biostatistics and Epidemiology (D.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Robert C Bauer
- From the Division of Translational Medicine and Human Genetics, Department of Medicine (S.T.N., R.C.B., D.J.R.), Penn Cardiovascular Institute, Department of Medicine (H.Z., M.P.R., D.J.R.), Department of Genetics (N.J.H., D.J.R.), and Department of Biostatistics and Epidemiology (D.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Danish Saleheen
- From the Division of Translational Medicine and Human Genetics, Department of Medicine (S.T.N., R.C.B., D.J.R.), Penn Cardiovascular Institute, Department of Medicine (H.Z., M.P.R., D.J.R.), Department of Genetics (N.J.H., D.J.R.), and Department of Biostatistics and Epidemiology (D.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Muredach P Reilly
- From the Division of Translational Medicine and Human Genetics, Department of Medicine (S.T.N., R.C.B., D.J.R.), Penn Cardiovascular Institute, Department of Medicine (H.Z., M.P.R., D.J.R.), Department of Genetics (N.J.H., D.J.R.), and Department of Biostatistics and Epidemiology (D.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia.
| | - Daniel J Rader
- From the Division of Translational Medicine and Human Genetics, Department of Medicine (S.T.N., R.C.B., D.J.R.), Penn Cardiovascular Institute, Department of Medicine (H.Z., M.P.R., D.J.R.), Department of Genetics (N.J.H., D.J.R.), and Department of Biostatistics and Epidemiology (D.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia.
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Dubland JA, Francis GA. Lysosomal acid lipase: at the crossroads of normal and atherogenic cholesterol metabolism. Front Cell Dev Biol 2015; 3:3. [PMID: 25699256 PMCID: PMC4313778 DOI: 10.3389/fcell.2015.00003] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/07/2015] [Indexed: 01/01/2023] Open
Abstract
Unregulated cellular uptake of apolipoprotein B-containing lipoproteins in the arterial intima leads to the formation of foam cells in atherosclerosis. Lysosomal acid lipase (LAL) plays a crucial role in both lipoprotein lipid catabolism and excess lipid accumulation as it is the primary enzyme that hydrolyzes cholesteryl esters derived from both low density lipoprotein (LDL) and modified forms of LDL. Evidence suggests that as atherosclerosis progresses, accumulation of excess free cholesterol in lysosomes leads to impairment of LAL activity, resulting in accumulation of cholesteryl esters in the lysosome as well as the cytosol in foam cells. Impaired metabolism and release of cholesterol from lysosomes can lead to downstream defects in ATP-binding cassette transporter A1 regulation, needed to offload excess cholesterol from plaque foam cells. This review focuses on the role LAL plays in normal cholesterol metabolism and how the associated changes in its enzymatic activity may ultimately contribute to atherosclerosis progression.
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Affiliation(s)
- Joshua A Dubland
- Department of Medicine, Centre for Heart Lung Innovation, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia Vancouver, BC, Canada
| | - Gordon A Francis
- Department of Medicine, Centre for Heart Lung Innovation, Providence Health Care Research Institute at St. Paul's Hospital, University of British Columbia Vancouver, BC, Canada
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Hendrikx T, Walenbergh SMA, Hofker MH, Shiri-Sverdlov R. Lysosomal cholesterol accumulation: driver on the road to inflammation during atherosclerosis and non-alcoholic steatohepatitis. Obes Rev 2014; 15:424-33. [PMID: 24629059 DOI: 10.1111/obr.12159] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 01/05/2014] [Accepted: 01/05/2014] [Indexed: 12/15/2022]
Abstract
Many studies show an association between the accumulation of cholesterol inside lysosomes and the progression towards inflammatory disease states that are closely related to obesity. While in the past, the knowledge regarding lysosomal cholesterol accumulation was limited to its association with plaque severity during atherosclerosis, recently, a growing body of evidence indicates a causal link between lysosomal cholesterol accumulation and inflammation. These findings make lysosomal cholesterol accumulation an important target for intervention in metabolic diseases that are characterized by the presence of an inflammatory response. In this review, we aim to show the importance of cholesterol trapping inside lysosomes to the development of inflammation by focusing upon cardiovascular disease and non-alcoholic steatohepatitis (NASH) in particular. We summarize current data supporting the hypothesis that lysosomal cholesterol accumulation plays a key role in the development of inflammation during atherosclerosis and NASH. In addition, potential mechanisms by which disturbed lysosomal function can trigger the inflammatory response, the challenges in improving cholesterol trafficking in macrophages and recent successful research directions will be discussed.
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Affiliation(s)
- T Hendrikx
- Department of Molecular Genetics, Maastricht University, Maastricht, The Netherlands
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Abstract
At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.
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Affiliation(s)
- Paul N Hopkins
- Cardiovascular Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.
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Inhibition of endoplasmic reticulum stress and atherosclerosis by 2-aminopurine in apolipoprotein e-deficient mice. ISRN PHARMACOLOGY 2013; 2013:847310. [PMID: 23984090 PMCID: PMC3747385 DOI: 10.1155/2013/847310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/08/2013] [Indexed: 01/07/2023]
Abstract
We previously reported that the apolipoprotein (apo) B48-carrying lipoproteins obtained from apoE knockout (apoE−/−) mice, so called E−/B48 lipoproteins, transformed mouse macrophages into foam cells and enhanced the phosphorylation of eukaryotic translation initiation factor 2α (eIF-2α). Furthermore, the eIF-2α phosphorylation inhibitor, 2-aminopurine (2-AP), attenuated E−/B48 lipoprotein-induced foam cell formation. The present report studied the effect of 2-AP on atherosclerosis in apoE−/− mice. Our results showed that the level of food intake, bodyweight, plasma cholesterol, and triglycerides was comparable in apoE−/− mice treated with or without 2-AP. However, the mean size of atherosclerotic lesions in the aorta sinus as well as the surface area of the entire aorta of 2-AP-treated apoE−/− mice were reduced by about 55% and 39%, respectively, compared to samples from untreated control apoE−/− mice. In addition, the 2-AP-treated apoE−/− mice showed a significant decrease in glucose-regulated protein 78 (GRP78) and phosphorylated eIF-2α in their aortic samples as compared to levels in untreated control apoE−/− mice. These observations suggest that endoplasmic reticulum stress is a causal mechanism for the development of atherosclerosis in apoE−/− mice and that therapeutic strategies can be developed for using eIF-2α phosphorylation inhibitors, such as 2-AP, to prevent or treat atherosclerosis.
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Bieghs V, Hendrikx T, van Gorp PJ, Verheyen F, Guichot YD, Walenbergh SMA, Jeurissen MLJ, Gijbels M, Rensen SS, Bast A, Plat J, Kalhan SC, Koek GH, Leitersdorf E, Hofker MH, Lütjohann D, Shiri-Sverdlov R. The cholesterol derivative 27-hydroxycholesterol reduces steatohepatitis in mice. Gastroenterology 2013; 144:167-178.e1. [PMID: 23041327 DOI: 10.1053/j.gastro.2012.09.062] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 08/16/2012] [Accepted: 09/19/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic steatohepatitis is characterized by hepatic steatosis with inflammation. Although steatosis is benign and reversible, inflammation can increase liver damage. Hepatic inflammation has been associated with accumulation of cholesterol in lysosomes of Kupffer cells. 27-Hydroxycholesterol (27HC), a derivative of cholesterol formed by CYP27A1, can mobilize cholesterol from the lysosomes to the cytoplasm. We investigated whether 27HC can change the intracellular distribution cholesterol and reduce hepatic inflammation in mice. METHODS We transplanted bone marrow from irradiated wild-type or Cyp27a1(-/-) mice to mice that do not express the low density lipoprotein receptor (Ldlr(-/-)), which are hyperlipidemic; 9 weeks later, mice were fed either regular chow or a high-fat, high-cholesterol (HFC) diet for 3 months. In a separate experiment, Ldlr(-/-) mice were given subcutaneous injections of 27HC and placed on regular chow or HFC diets for 3 weeks. Blood and liver tissues samples were collected and analyzed for intracellular cholesterol distribution and inflammation. RESULTS In Ldlr(-/-) mice that received bone marrow transplants from Cyp27a1(-/-) mice, lysosomes of Kupfer cells had a greater accumulation of cholesterol than those of mice that received bone marrow from wild-type mice, after the HFC diet. Liver histology and gene expression analyses showed increased inflammation and liver damage in mice given bone marrow transplants from Cyp27a1(-/-) mice and placed on the HFC diet. Administration of 27HC to Ldlr(-/-) mice, following the HFC diet, reduced the accumulation of lysosomal cholesterol and hepatic inflammation, compared with mice that were not given 27HC. CONCLUSIONS Accumulation of cholesterol in lysosomes of Kupfer cells promotes hepatic inflammation in mice. The cholesterol derivative 27HC reduces accumulation of cholesterol in lysosomes and might be used to treat non-alcoholic steatohepatitis.
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Affiliation(s)
- Veerle Bieghs
- Department of Molecular Genetics, Maastricht University, Maastricht, the Netherlands
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Ouimet M, Marcel YL. Regulation of Lipid Droplet Cholesterol Efflux From Macrophage Foam Cells. Arterioscler Thromb Vasc Biol 2012; 32:575-81. [DOI: 10.1161/atvbaha.111.240705] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cholesterol efflux from macrophages is the first and potentially most important step in reverse cholesterol transport, a process especially relevant to atherosclerosis and to the regression of atherosclerotic plaques. Increasingly, lipid droplet (LD) cholesteryl ester (CE) hydrolysis is being recognized as a rate-limiting step in cholesterol efflux. The traditional view on macrophage CE hydrolysis is that this pathway is entirely dependent on the action of neutral hydrolases, and numerous candidate CE hydrolases have been proposed to play a role in lipid hydrolysis in macrophages and atherogenesis. Although the exact identity of macrophage-specific CE hydrolases remains to be clarified, a common point to all of these studies is that enhancing LD-associated CE hydrolysis increases cholesterol efflux and is antiatherogenic. Understanding how cholesterol is mobilized from LDs offers new steps for modulating cholesterol efflux, and recently a role for autophagy and lysosomal acid lipase in macrophage lipolysis has emerged. Autophagy and lysosomal acid lipase thus represent novel therapeutic targets to enhance macrophage reverse cholesterol transport. This review discusses our current understanding of the relationship between macrophage LDs and atherosclerosis and presents recent insights into the mechanisms for LD CE hydrolysis in macrophage foam cells.
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Affiliation(s)
- Mireille Ouimet
- From the Department of Biochemistry, Microbiology, and Immunology (M.O., Y.L.M.), Department of Pathology and Laboratory Medicine (Y.L.M.), University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Yves L. Marcel
- From the Department of Biochemistry, Microbiology, and Immunology (M.O., Y.L.M.), Department of Pathology and Laboratory Medicine (Y.L.M.), University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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Wu G, Huang J, Wei G, Liu L, Pang S, Yan B. LAMP-2 gene expression in peripheral leukocytes is increased in patients with coronary artery disease. Clin Cardiol 2011; 34:239-43. [PMID: 21462217 PMCID: PMC6652621 DOI: 10.1002/clc.20870] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 11/08/2010] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Coronary artery disease (CAD) is a common complex disease that is caused by interaction between genetic and environmental factors. Accumulating evidence indicates that foam cells in the atherosclerotic plaques exhibit the characteristics of lysosomal storage diseases, namely lysosomal accumulation of indigested materials. In patients with lysosomal storage diseases, lysosomal accumulation of lipids and cholesterols in atherosclerotic plaque cells has been observed. However, the roles of lysosomal hydrolases and proteins in the pathogenesis of atherosclerosis and CAD remain unclear. HYPOTHESIS Lysosomal hydrolases and proteins may be involved in the pathogenesis of atherosclerosis and CAD by affecting lipid and cholesterol metabolism. METHODS Expression levels of LAMP-2, a lysosomal membrane marker gene, in the peripheral leukocytes of CAD patients (n = 134) and age- and sex-matched healthy controls (n = 80) were examined at transcription and protein levels with reverse transcriptase-polymerase chain reaction and Western blot analyses, respectively. The results were compared between CAD patients and healthy controls. RESULTS LAMP-2 gene expression and LAMP-2 protein levels were significantly increased in the peripheral leukocytes of CAD patients, compared with healthy controls. Furthermore, multivariate logistic regression analyses revealed that CAD is significantly associated with LAMP-2 gene expression levels (odds ratio [OR] 8.84, 95% confidence interval [CI]: 2.15-36.40, P = 0.003) or LAMP-2 protein levels (OR 2.03, 95% CI: 1.15-3.59, P = 0.015). CONCLUSIONS In CAD patients, LAMP-2 gene expression in the peripheral leukocytes was significantly increased than were controls, which indicates lysosomal accumulation. These data suggest that insufficient lysosomal hydrolases and proteins may lead to abnormal lipid and cholesterol metabolism, which cause initiation and progression of atherosclerosis and CAD.
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Affiliation(s)
- Guanghua Wu
- Shandong Provincial Key Laboratory of Cardiac Disease Diagnosis and Treatment
- Division of Cardiac Surgery
| | - Jian Huang
- Shandong Provincial Key Laboratory of Cardiac Disease Diagnosis and Treatment
| | - Guanghe Wei
- Division of Cardiology, Jining Medical College Affiliated Hospital, Jining Medical College, Jining, Shandong, China
| | - Lixin Liu
- Division of Cardiology, Jining Medical College Affiliated Hospital, Jining Medical College, Jining, Shandong, China
| | - Shuchao Pang
- Shandong Provincial Key Laboratory of Cardiac Disease Diagnosis and Treatment
| | - Bo Yan
- Shandong Provincial Key Laboratory of Cardiac Disease Diagnosis and Treatment
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Rosenbaum AI, Maxfield FR. Niemann-Pick type C disease: molecular mechanisms and potential therapeutic approaches. J Neurochem 2011; 116:789-95. [PMID: 20807315 DOI: 10.1111/j.1471-4159.2010.06976.x] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cholesterol is an important lipid of mammalian cells. Its unique physicochemical properties modulate membrane behavior and it serves as the precursor for steroid hormones, oxysterols and vitamin D. Cholesterol is effluxed from the late endosomes/lysosomes via the concerted action of at least two distinct proteins: Niemann-Pick C (NPC)1 and NPC2. Mutations in these two proteins manifest as NPC disease - a very rare, usually fatal, autosomal, recessive, neurovisceral, lysosomal storage disorder. In this review, we discuss the possible mechanisms of action for NPC1 and NPC2 in mediating cholesterol efflux, as well as the different therapeutic approaches being pursued for the treatment of this lipid storage disorder.
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Affiliation(s)
- Anton I Rosenbaum
- Department of Biochemistry, Weill Cornell Medical College, New York, New York 10065, USA
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29
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Abstract
Cholesterol-engorged macrophage foam cells are a critical component of the atherosclerotic lesion. Reducing the sterol deposits in lesions reduces clinical events. Sterol accumulations within lysosomes have proven to be particularly hard to mobilize out of foam cells. Moreover, excess sterol accumulation in lysosomes has untoward effects, including a complete disruption of lysosome function. Recently, we demonstrated that treatment of sterol-engorged macrophages in culture with triglyceride-containing particles can reverse many of the effects of cholesterol on lysosomes and dramatically reduce the sterol burden in these cells. This article describes what is known about lysosomal sterol engorgement, discusses the possible mechanisms by which triglyceride could produce its effects, and evaluates the possible positive and negative effects of reducing the lysosomal cholesterol levels in foam cells.
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Affiliation(s)
- W Gray Jerome
- Department of Pathology, U-2206 Medical Center North Vanderbilt University School of Medicine 1161 21st Avenue, South Nashville, TN 37232-32561, USA, Tel.: +1 615 322 5530
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Hullin-Matsuda F, Luquain-Costaz C, Bouvier J, Delton-Vandenbroucke I. Bis(monoacylglycero)phosphate, a peculiar phospholipid to control the fate of cholesterol: Implications in pathology. Prostaglandins Leukot Essent Fatty Acids 2009; 81:313-24. [PMID: 19857945 DOI: 10.1016/j.plefa.2009.09.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 09/21/2009] [Accepted: 09/21/2009] [Indexed: 12/15/2022]
Abstract
Bis(monoacylglycero)phosphate (BMP) is a structural isomer of phosphatidylglycerol that exhibits an unusual sn1:sn1' stereoconfiguration, based on the position of the phosphate moiety on its two glycerol units. Early works have underlined the high concentration of BMP in the lysosomal compartment, especially during some lysosomal storage disorders and drug-induced phospholipidosis. Despite numerous studies, both biosynthetic and degradative pathways of BMP remained not completely elucidated. More recently, BMP has been localized in the internal membranes of late endosomes where it forms specialized lipid domains. Its involvement in both dynamics and lipid/protein sorting functions of late endosomes has started to be documented, especially in the control of cellular cholesterol distribution. BMP also plays an important role in the late endosomal/lysosomal degradative pathway. Another peculiarity of BMP is to be naturally enriched in docosahexaenoic acid and/or to specifically incorporate this fatty acid compared to other polyunsaturated fatty acids, which may confer specific biophysical and functional properties to this phospholipid. This review summarizes and updates our knowledge on BMP with an emphasis on its possible implication in human health and diseases, especially in relation to cholesterol homeostasis.
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Affiliation(s)
- F Hullin-Matsuda
- Université de Lyon, UMR 870 Inserm, Insa-Lyon, UMR 1135 Inra, Univ Lyon 1, Hospices Civils de Lyon, IMBL, 20 Ave A. Einstein, 69621 Villeurbanne, France
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Mathieu JM, Schloendorn J, Rittmann BE, Alvarez PJJ. Medical bioremediation of age-related diseases. Microb Cell Fact 2009; 8:21. [PMID: 19358742 PMCID: PMC2674406 DOI: 10.1186/1475-2859-8-21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 04/09/2009] [Indexed: 12/12/2022] Open
Abstract
Catabolic insufficiency in humans leads to the gradual accumulation of a number of pathogenic compounds associated with age-related diseases, including atherosclerosis, Alzheimer's disease, and macular degeneration. Removal of these compounds is a widely researched therapeutic option, but the use of antibodies and endogenous human enzymes has failed to produce effective treatments, and may pose risks to cellular homeostasis. Another alternative is "medical bioremediation," the use of microbial enzymes to augment missing catabolic functions. The microbial genetic diversity in most natural environments provides a resource that can be mined for enzymes capable of degrading just about any energy-rich organic compound. This review discusses targets for biodegradation, the identification of candidate microbial enzymes, and enzyme-delivery methods.
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Affiliation(s)
- Jacques M Mathieu
- Dept. of Civil and Environmental Engineering, Rice University, Houston, TX, USA
| | - John Schloendorn
- Dept. of Civil and Environmental Engineering, Arizona State University, Tempe, AZ, USA
| | - Bruce E Rittmann
- Dept. of Civil and Environmental Engineering, Arizona State University, Tempe, AZ, USA
| | - Pedro JJ Alvarez
- Dept. of Civil and Environmental Engineering, Rice University, Houston, TX, USA
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Wu D, Sharan C, Yang H, Goodwin JS, Zhou L, Grabowski GA, Du H, Guo Z. Apolipoprotein E-deficient lipoproteins induce foam cell formation by downregulation of lysosomal hydrolases in macrophages. J Lipid Res 2007; 48:2571-8. [PMID: 17720994 DOI: 10.1194/jlr.m700217-jlr200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Apolipoprotein E (apoE) deficiency has been suggested to induce foam cell formation. Using lipoproteins obtained from wild-type mice and apoE-deficient mice expressing apoB-48 but not apoB-100, we studied apoE-deficient lipoprotein-induced changes in lipoprotein catabolism and protein expression in mouse peritoneal macrophages (MPMs). Our data demonstrate that incubation of MPMs with apoE-deficient lipoproteins induced intracellular lipoprotein, cholesteryl ester, and triglyceride accumulation, which was associated with a time-related decline in apoE-deficient lipoprotein degradation in MPMs. Confocal microscopy analysis indicated that the accumulated lipids were localized in lysosomes. ApoE-deficient lipoproteins reduced the protein levels of lysosomal acid lipase, cathepsin B, and cation-dependent mannose 6 phosphate receptor (MPR46). Exogenous apoE reduced apoE-deficient lipoprotein-induced lipid accumulation and attenuated the suppressive effect of apoE-deficient lipoproteins on lysosomal hydrolase and MPR46 expression. Although oxidized lipoproteins also increased lipid contents in MPMs, exogenous apoE could not attenuate oxidized lipoprotein-induced lipid accumulation. Our in vivo studies also showed that feeding apoE-deficient mice a high-fat diet resulted in cholesteryl ester and triglyceride accumulation and reduced lysosomal hydrolase expression in MPMs. These data suggest that apoE-deficient lipoproteins increase cellular lipid contents through pathways different from those activated by oxidized lipoproteins and that reducing lysosomal hydrolases in macrophages might be a mechanism by which apoE-deficient lipoproteins result in intralysosomal lipoprotein accumulation, thereby inducing foam cell formation.
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Affiliation(s)
- DongFang Wu
- Department of Cardiovascular Biology, Meharry Medical College, Nashville, TN 37208, USA
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Cox BE, Griffin EE, Ullery JC, Jerome WG. Effects of cellular cholesterol loading on macrophage foam cell lysosome acidification. J Lipid Res 2007; 48:1012-21. [PMID: 17308299 DOI: 10.1194/jlr.m600390-jlr200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophages incubated with mildly oxidized low density lipoprotein (OxLDL), aggregated low density lipoprotein (AggLDL), or cholesteryl ester-rich lipid dispersions (DISPs) accumulate cholesterol in lysosomes followed by an inhibition of lysosomal cholesteryl ester (CE) hydrolysis. The variety of cholesterol-containing particles producing inhibition of hydrolysis suggests that inhibition may relate to general changes in lysosomes. Lysosome pH is a key mediator of activity and thus is a potential mechanism for lipid-induced inhibition. We investigated the effects of cholesterol accumulation on THP-1 macrophage lysosome pH. Treatment with OxLDL, AggLDL, and DISPs resulted in inhibition of the lysosome's ability to maintain an active pH and concomitant decreases in CE hydrolysis. Consistent with an overall disruption of lysosome function, exposure to OxLDL or AggLDL reduced lysosomal apolipoprotein B degradation. The lysosomal cholesterol sequestration and inactivation are not observed in cholesterol-equivalent cells loaded using acetylated low density lipoprotein (AcLDL). However, AcLDL-derived cholesterol in the presence of progesterone (to block cholesterol egression from lysosomes) inhibited lysosome acidification. Lysosome inhibition was not attributable to a decrease in the overall levels of vacuolar ATPase. However, augmentation of membrane cholesterol in isolated lysosomes inhibited vacuolar ATPase-dependent pumping of H+ ions into lysosomes. These data indicate that lysosomal cholesterol accumulation alters lysosomes in ways that could exacerbate foam cell formation and influence atherosclerotic lesion development.
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Affiliation(s)
- Brian E Cox
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Zschenker O, Illies T, Ameis D. Overexpression of lysosomal acid lipase and other proteins in atherosclerosis. J Biochem 2006; 140:23-38. [PMID: 16877765 DOI: 10.1093/jb/mvj137] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Atherosclerosis is one of the major causes of morbidity and mortality in the western world. The existing data of elevated expression levels of proteins like DNA damage and DNA repair enzymes in human atherosclerotic plaques are reviewed. From the literature, the effect of overexpression of different proteins using adenoviral vectors or the model of transgenic mice on the development of atherosclerosis will be discussed. Special focus is placed on the lysosomal acid lipase (LAL), because LAL connects extra-cellular with intra-cellular lipid metabolism and is the only hydrolase for cleavage of cholesteryl esters delivered to the lysosomes. Patients with a deficiency of LAL show an accumulation of lipids in the cells and develop pre-mature atherosclerosis. To answer the question of the influence of LAL in atherosclerosis if overexpressed, we show for the first time data of transgenic mice overexpressing LAL and the effect on the lipid level.
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Affiliation(s)
- Oliver Zschenker
- Medical Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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35
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Jerome WG. Advanced atherosclerotic foam cell formation has features of an acquired lysosomal storage disorder. Rejuvenation Res 2006; 9:245-55. [PMID: 16706652 DOI: 10.1089/rej.2006.9.245] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Atherosclerosis is a disease of large- and medium-sized arteries. Complications from atherosclerosis remain a serious cause of morbidity and mortality in industrialized countries. The disease begins very early in life and effects most people in the West. However, because the progression of the disease is slow, symptoms usually do not occur until after the fifth decade of life. Because atherosclerosis is a ubiquitous occurrence throughout the world, as life expectancy is prolonged most populations will see increasing numbers of deaths from complications of atherosclerosis unless there are dramatic advances in treatment. Because it begins so early in life, current treatment is aimed at slowing or reversing the progression of the disease rather than eliminating the initiating steps. Changes in diet and exercise, cholesterol-lowering drugs, and improvements in surgical treatments have made significant inroads into prolonging life, but much work is still required. To proceed further, a better understanding is needed of the underlying causes of disease progression. In this regard, evidence is mounting that the foam cells of the lesion (a critical cell in atherosclerosis progression) exhibit characteristics of an acquired lysosomal storage disorder. In this review the evidence for this conclusion is reviewed and the ramifications of this conclusion are explored with regard to the understanding of disease progression mechanisms, possible improvements in treatment, and their role in increasing life expectancy.
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Affiliation(s)
- W Gray Jerome
- Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2561, USA.
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36
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Ho GYH, Eikelboom JW, Hankey GJ, Wong CR, Tan SL, Chan JBC, Chen CPLH. Methylenetetrahydrofolate Reductase Polymorphisms and Homocysteine-Lowering Effect of Vitamin Therapy in Singaporean Stroke Patients. Stroke 2006; 37:456-60. [PMID: 16397167 DOI: 10.1161/01.str.0000199845.27512.84] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Increased plasma total homocysteine (tHcy) levels are a risk factor for stroke and can be reduced with vitamin therapy. However, data on the tHcy-lowering effects of vitamins are limited largely to white populations. Thus, we aimed to determine in Singaporean patients with recent stroke: (1) the efficacy of vitamin therapy (folic acid, vitamin B12, and B6) on lowering tHcy, and (2) whether efficacy is modified by Methylenetetrahydrofolate reductase (MTHFR) gene polymorphism(s). METHODS A total of 443 eligible patients were recruited after presenting with ischemic stroke within the past 7 months. Patients were randomized to receive either placebo or vitamins. Fasting blood samples collected at baseline and at 1 year were assayed for levels of plasma tHcy. Patients were genotyped for MTHFR C677T and A1298C polymorphisms. RESULTS Mean baseline tHcy was similar in the 2 groups (placebo 13.7 micromol/L; vitamins 14.0 micromol/L; P=0.70). At 1 year, mean tHcy was 14.5 micromol/L in the placebo group compared with 10.7 micromol/L in the vitamin group (difference 3.8 micromol/L; 95% CI, 2.8 to 4.8 micromol/L; P<0.0001). MTHFR C677T genotype was an independent determinant of tHcy levels at baseline (P=0.005), but A1298C was not (P=0.08). Neither polymorphism significantly influenced the effect of vitamin therapy on tHcy at 1 year. The magnitude of the reduction in tHcy levels at 1 year with vitamin therapy was similar, irrespective of MTHFR genotypes. CONCLUSIONS Vitamin therapy reduces mean tHcy levels by 3.8 micromol/L in the Singaporean stroke population studied. MTHFR C677T but not A1298C is independently associated with tHcy levels at baseline, and neither impacts the tHcy-lowering effect of vitamins used in this study.
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Affiliation(s)
- Grace Y-H Ho
- Department of Neurology, Singapore General Hospital, Singapore
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Tanaka K, Sata M, Fukuda D, Suematsu Y, Motomura N, Takamoto S, Hirata Y, Nagai R. Age-associated aortic stenosis in apolipoprotein E-deficient mice. J Am Coll Cardiol 2005; 46:134-41. [PMID: 15992647 DOI: 10.1016/j.jacc.2005.03.058] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Revised: 03/16/2005] [Accepted: 03/22/2005] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The present study was designed to assess aortic valve morphology and function in mice of advanced age. We also evaluated the potential contribution of bone-marrow-derived cells to the pathogenesis of aortic stenosis. BACKGROUND Age-associated valvular degeneration is characterized by lipid accumulation, collagen deposition, and calcification containing smooth muscle-like cells and osteoblast-like cells. Cellular and molecular factors that mediate these changes remain unknown. METHODS We extensively examined the aortic valves of senile wild-type and apolipoprotein E (ApoE)-/- mice with echocardiography. The aortic valves were analyzed by immunohistochemistry and electron microscopy. The bone marrow of wild-type and ApoE-/- mice was reconstituted with that of green fluorescent protein (GFP) or beta-galactosidase (LacZ) mice, which expressed GFP or LacZ ubiquitously. RESULTS Transaortic flow velocity was correlated with age in wild-type and ApoE-/- mice. The aortic valves of old ApoE-/- mice showed sclerosis that resembled the pathology of human aortic stenosis. A significant number of GFP-positive cells (10.7 +/- 4.1%) in the sclerotic valves of ApoE-/- mice expressed alpha-smooth muscle actin, whereas most of the GFP-positive cells were identified as endothelial cells or macrophages in wild-type mice. There were bone-marrow-derived cells that were positive for osteoblast-related proteins near the sites of ectopic calcification. The sclerotic valves displayed frequent apoptotic cell death and chemokine expression. CONCLUSIONS Senile ApoE-deficient mice display aortic valve sclerosis that is similar to that observed in humans. The sclerotic valves displayed frequent apoptotic cell death and chemokine expression. Smooth muscle-like cells observed in degenerative valves might derive, at least in part, from bone marrow.
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Affiliation(s)
- Kimie Tanaka
- Department of Cardiovascular Medicine, University of Tokyo Graduate School of Medicine, Tokyo, Japan
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38
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Dusitanond P, Eikelboom JW, Hankey GJ, Thom J, Gilmore G, Loh K, Yi Q, Klijn CJM, Langton P, van Bockxmeer FM, Baker R, Jamrozik K. Homocysteine-Lowering Treatment With Folic Acid, Cobalamin, and Pyridoxine Does Not Reduce Blood Markers of Inflammation, Endothelial Dysfunction, or Hypercoagulability in Patients With Previous Transient Ischemic Attack or Stroke. Stroke 2005; 36:144-6. [PMID: 15569860 DOI: 10.1161/01.str.0000150494.91762.70] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Epidemiological and laboratory studies suggest that increasing concentrations of plasma homocysteine (total homocysteine [tHcy]) accelerate cardiovascular disease by promoting vascular inflammation, endothelial dysfunction, and hypercoagulability.
Methods—
We conducted a randomized controlled trial in 285 patients with recent transient ischemic attack or stroke to examine the effect of lowering tHcy with folic acid 2 mg, vitamin B
12
0.5 mg, and vitamin B
6
25 mg compared with placebo on laboratory markers of vascular inflammation, endothelial dysfunction, and hypercoagulability.
Results—
At 6 months after randomization, there was no significant difference in blood concentrations of markers of vascular inflammation (high-sensitivity C-reactive protein [
P
=0.32]; soluble CD40L [
P
=0.33]; IL-6 [
P
=0.77]), endothelial dysfunction (vascular cell adhesion molecule-1 [
P
=0.27]; intercellular adhesion molecule-1 [
P
=0.08]; von Willebrand factor [
P
=0.92]), and hypercoagulability (P-selectin [
P
=0.33]; prothrombin fragment 1 and 2 [
P
=0.81]; D-dimer [
P
=0.88]) among patients assigned vitamin therapy compared with placebo despite a 3.7-μmol/L (95% CI, 2.7 to 4.7) reduction in total homocysteine (tHcy).
Conclusions—
Lowering tHcy by 3.7 μmol/L with folic acid-based multivitamin therapy does not significantly reduce blood concentrations of the biomarkers of inflammation, endothelial dysfunction, or hypercoagulability measured in our study. The possible explanations for our findings are: (1) these biomarkers are not sensitive to the effects of lowering tHcy (eg, multiple risk factor interventions may be required); (2) elevated tHcy causes cardiovascular disease by mechanisms other than the biomarkers measured; or (3) elevated tHcy is a noncausal marker of increased vascular risk.
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Affiliation(s)
- P Dusitanond
- Stroke Unit, Department of Neurology, Royal Perth Hospital, Perth, Australia
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39
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Abstract
PURPOSE OF REVIEW Atherosclerosis remains the leading cause of death in the developed countries. In addition to lipid-lowering drugs - statins, dietary control, and exercise, new approaches are needed for the treatment and prevention of atherosclerosis. This review will focus on the role(s) of lysosomal acid lipase and its use as an enzyme therapy to reduce atherosclerotic lesions in a mouse model and to examine the molecular basis supporting this novel strategy and its mechanism of effect. RECENT FINDINGS Administration of human lysosomal acid lipase via tail vein into mice with atherosclerosis eliminates early aortic and coronary ostial lesions and reduces lesional size in advanced disease. The reduction of advanced lesional area is related to decreases in foamy macrophages, collagen positive areas, and necrotic areas. Compared with sham-treated mice, the human lysosomal acid lipase-treated mice also have reduced levels of plasma cholesteryl esters, and reduced levels of hepatic cholesterol and triglycerides. SUMMARY These studies indicate that administrated lysosomal acid lipase affects the atherogenesis by at least two mechanisms: (1) direct targeting of lesional macrophages with resultant decreases in cholesteryl esters and triglyceride in the lysosomes of macrophages in the lesions; (2) systemic effects that mediate the liver to reduce the hepatic cholesteryl ester and triglyceride release, possibly leading to reduced production of VLDL and LDL.
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Affiliation(s)
- Hong Du
- The Children's Hospital Research Foundation of Cincinnati Children's Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio 45229-3039, USA
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