- Email: [email protected]
A loss-of-function variant in OSBPL1A predisposes to low plasma HDL cholesterol levels and impaired cholesterol efflux capacity
Abstracts / Atherosclerosis 252 (2016) e236ee264
EAS16-0030, INTRACELLULAR LIPID METABOLISM. CONVERGENT SIGNALING PATHWAYS CONTROLLED BY LRP1 CYTOPLASMIC AND EXTRACELLULAR DOMAINS LIMIT CELLULAR CHOLESTEROL ACCUMULATION P. Boucher 1, Z. El Asmar 1, J. Terrand 1, M. Jenty 1, L. Host 1, M. Mlih 1, A. Zerr 1, H. Justiniano 1, L. R. Matz 1, C. Boudier 1, E. Scholler 1, J.M. 3, C. Schaeffer 3, V.D. Alain 3, J. Garnier 2, D. Bertaccini 3, D. Thierse 4 1 Herz . UMR CNRS 7213, Physiology, Strasbourg Cedex, France; 2 Institut de G en etique et de Biologie Mol eculaire et Cellulaire, Stem Cell Department, etrie Strasbourg Cedex, France; 3 CNRS- UMR 7178, Laboratoire de Spectrom de Masse BioOrganique LSMBO, Strasbourg, France; 4 UT Southwestern Medical Center, Department of Molecular Genetics and Center for Translational Neurodegeneration Research, Dallas, TX, USA Objectives: The Low Density Lipoprotein (LDL) receptor-related protein 1 (LRP1) is a ubiquitously expressed cell surface receptor. We previously demonstrated that a LRP1/Wnt5a pathway limits cholesterol intracellular accumulation. However, the underlying mechanisms are unknown. Methods: We used cells and mice over expressing Wnt5a in adipose tissue to determine how LRP1 regulates Wnt5a, and how Wnt5a prevents intracellular cholesterol accumulation Results: Our data show that the extracellular (a) chain of LRP1 mediates TGFb-induced enhancement of Wnt5a which limits intracellular cholesterol accumulation by inhibiting cholesterol biosynthesis and by promoting cholesterol export. We moreover demonstrate that the cytoplasmic (b) chain of LRP1 suffices to limit cholesterol accumulation in LRP1-/- cells. Through binding of Erk2 to the second of its carboylterminal NPxY motifs, LRP1 b-chain positively regulates the expression of ABCA1 and of neutral cholesterol ester hydrolase (NCEH1). Conclusions: These results highlight unexpected functions of LRP1 and the canonical Wnt5a pathway, and new therapeutic potential in cholesterol-associated disorders, including cardiovascular diseases.
EAS16-0283, INTRACELLULAR LIPID METABOLISM. MONOGLYCERIDE LIPASE REGULATES ENDOCANNABINOID TONE AND ATHEROSCLEROTIC PLAQUE STRUCTURE IN APOLIPOPROTEIN EDEFICIENT MICE N. Vujic 1, S. Schlager 1, T.O. Eichmann 2, M. Goeritzer 1, C.T. MadreiterSokolowski 1, S. Schauer 3, A. Lass 2, R. Zimmermann 2, G. Hoefler 3, W.F. Graier 1, B. Radovic 1, D. Kratky 1. 1 Medical University of Graz, Institute of Molecular Biology and Biochemistry, Graz, Austria; 2 University of Graz, Institute of Molecular Biosciences, Graz, Austria; 3 Medical University of Graz, Institute of Pathology, Graz, Austria Objectives: Monoglyceride lipase (MGL) mediates the last step of lipolysis by hydrolyzing monoglyceride to glycerol and fatty acid. Among substrates for MGL activity is 2-arachidonoylglycerol (2-AG), the most abundant endocannabinoid in mammals. 2-AG acts as full agonist on cannabinoid receptors (CBR) 1 and 2, which are biphasically distributed in brain and immune cells, respectively. Based on the direct involvement of MGL in lipolysis and its indirect effects on endocannabinoid homeostasis and thus immune response, we hypothesized that MGL deficiency modulates CB2Rmediated signaling and atherogenesis. Methods: We generated apolipoprotein E/MGL double-knockout (DKO) mice, challenged them with western-type diet, and assessed atherogenesis. Results: We found systemically elevated 2-AG concentrations in DKO mice. Fasting plasma lipids were comparable between genotypes, however, DKO mice had reduced hepatic steatosis and delayed chylomicron secretion. DKO macrophages were able to fully respond to 2-AG stimulation, arguing against CB2R desensitization, and were resistant to foam cell formation. Although atherosclerotic plaque was enlarged in DKO mice, plaque composition showed reduced relative abundance of necrotic core and macrophages and elevated collagen content and
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fibrotic cap thickness, leading to the formation of stabilized lesions. Increased plaque collagen may be a consequence of higher relative abundance of smooth muscle cells within the lesions. Pharmacologic CB2R antagonism reversed atherosclerotic plaque structure, suggesting that the observed lesion phenotype is the consequence of potentiated CB2R signaling in DKO mice. Conclusions: Our results demonstrate that MGL deficiency strongly regulates endocannabinoid homeostasis and atherogenesis. Despite increased lesion size, elevated 2-AG concentrations have protective effects on plaque stability.
EAS16-0265, INTRACELLULAR LIPID METABOLISM. LACK OF ADIPOSE TISSUE LIPOLYSIS PROTECTS AGAINST PRESSURE OVERLOAD-INDUCED HEART FAILURE A. Foryst-Ludwig 1, J. Salatzki 1, S. Brix 1, Z. Ban 1, J. Grune 1, R. Klopfleisch 2, M. Rothe 3, E. Kershaw 4, U. Kintscher 1. 1 Institute of €tsmedizin Berlin, Berlin, Germany; Pharmacology, CCR, Charite-Universita 2 Institute of Veterinary Pathology, Freie Universitaet Berlin, Berlin, Germany; 3 Lipidomix, Lipidomix GmbH, Berlin, Germany; 4 Division of Endocrinology- Diabetes- and Metabolism, University of Pittsburgh, Pittsburgh, USA Objectives: Cardiac metabolism undergoes substantial changes in response to pathological hypertrophy (PH), characterized by decreased free fatty acid (FFA) oxidation and a loss of metabolic flexibility. In this study we investigated the impact of AT lipolysis, regulated by Adipose Triglyceride Lipase (ATGL) on the development of PH in a pressure overload-induced cardiac hypertrophy model in mice. Methods: AT-specific ATGL-deficient (atATGL-KO) and wild type mice (WT) underwent aortic constriction (TAC) or sham surgery. Echocardiographic analysis was performed 11 weeks after surgery. Left ventricular mass (LVM) and ejection fraction (EF%) were calculated. Insulin sensitivity was assessed by glucose and insulin tolerance test. FAs were measured in serum and FA serum profiling was performed using HPLC/MS technology. Results: Echocardiographic analysis revealed that LVM in WT were significantly higher compared to atATGL-KO after TAC. Moreover, WT-TAC animals showed significant reduction of EF ([%] WT: 28.81±6.9 atATGL-KO: 42.39±4.5; p<0.01). In line with those findings cardiac fibrosis, cardiac diameter and expression of beta-MyHC, a marker specific for PH, were markedly higher in WT-TAC than in atATGL-KO-TAC. Using serum FAprofiling we identified specific set of FAs, significantly reduced only in the serum of atATGL-KO-TAC mice. Importantly, atATGL-KO-TAC showed overall lower serum FFA-levels and higher insulin sensitivity when compared to WT-TAC. Conclusions: In this study, we demonstrate that atATGL is crucial for the development of pressure overload-induced PH. The lack of ATGL in adipose tissue, the associated reduced lipolysis/ altered serum lipid profile and the subsequent switch in cardiac metabolism from FFA oxidation to glycolysis are potential underlying mechanisms of this process.
EAS16-0731, INTRACELLULAR LIPID METABOLISM. A LOSS-OF-FUNCTION VARIANT IN OSBPL1A PREDISPOSES TO LOW PLASMA HDL CHOLESTEROL LEVELS AND IMPAIRED CHOLESTEROL EFFLUX CAPACITY J. van Capelleveen 1, J. Pirhonen 2, M.M. Motazacker 1, M. WeberBoyvat 3, M. Jauhiainen 4, G.K. Hovingh 1, G.M. Dallinga-Thie 1, V. Olkkonen 2. 1 Academic Medical Center, Vascular Medicine, Amsterdam, Netherlands; 2 Faculty of Medicine, University of Helsinki, Department of Anatomy, Helsinki, Finland; 3 Minerva foundation Institute for Medical Research, Minerva, Helsinki, Finland; 4 National Institute for Health and Welfare, Genomics and biomarkers unit, Helsinki, Finland Objectives: Oxysterol-binding protein-like (OSBPL) proteins have a function in cellular cholesterol homeostasis, however their specific contribution has not been elucidated in humans
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Abstracts / Atherosclerosis 252 (2016) e236ee264
Methods: In subjects with high-density-lipoprotein cholesterol (HDL-C) <1st percentile in the general population (n¼40) we sequenced the coding region of 195 lipid-related genes including OSBPL1A. Next, we investigated the composition and function of HDL from the carriers and non-carriers, the ability of skin fibroblasts to efflux cholesterol and studied the properties of the mutant protein in cultured HuH-7 cells. Results: We identified a heterozygous variant OSBPL1A p.C39X encoding a short truncated protein fragment, that co-segregated with low plasma HDL-C in a small pedigree. In line plasma apoA-I levels were lower in mutation carriers. Other HDL parameters were not different. Fibroblasts from a p.C39X carrier showed reduced cholesterol efflux potential to HDL and apoA-I, p<0.05, as well as lower OSBPL1A protein expression on western blot. Cholesterol efflux from labelled Raw264.7 macrophages to serum showed lower efflux capacity for serum derived from p.C39X carriers compared to family wildtype controls, p<0.01, but no difference was observed for efflux to isolated HDL. The OSBPL-39X protein did not colocalize to the endosomes confirming impaired functionality
(C57bl/6), APP over-expressing and BACE1 knockout (BACE1KO) mice fed either regular chow or high fat (HF) diet (45% fat) for 20 weeks to drive obesity and insulin resistance. Results: BACE1 protein is detectable in endothelial and smooth muscle cells in human and mouse arteries. HF-fed BACE1KO, compared to dietinduced obese wild-type (DIO), mice were protected from endothelial dysfunction (Ach AUC: BACE1KO 30163 ± 4339, DIO 18670 ± 1445; P< 0.01), and hypertension (P< 0.05). In contrast, APP over-expressing mice with increased tissue b-amyloid, exhibited impaired vascular responses (Ach AUC: APP 24289 ± 3444, WT 39805 ± 3309; P< 0.05), and worsened hypertension (P< 0.05) on regular chow, independent of body weight. Conclusions: We suggest that amyloid processing has a role in normal vascular function with aberrant processing leading to endothelial dysfunction and hypertension. Thus BACE1 inhibitors may be a novel treatment for diabetes-induced vascular disease.
EAS16-0697, NOVEL PATHWAYS IN ATHEROSCLEROSIS. A LIPID METABOLITE PROFILE IN ATHEROSCLEROTIC PLAQUES ASSOCIATED WITH INCREASED INFLAMMATION AND CARDIOVASCULAR RISK € rkbacka 1, A. Edsfeldt 1, A. Danielsson 2, M. Wigren 1, H. L. Tomas 1, H. Bjo Grufman 1, A. Persson 1, C. Prehn 3, J. Adamski 3, J. Nilsson 1, I. Gonçalves 1. 1 Experimental Cardiovascular Research Unit, Department of €, Sweden; 2 Molecular Metabolism, Department of Clinical Sciences, Malmo €, Sweden; 3 Institute of Experimental Genetics, Clinical Sciences, Malmo Helmholtz Center Munich, Munich, Germany Objectives: Atherosclerosis is characterized by the retention of lipids and chronic inflammation in the vasculature. In the present study we asked whether a certain lipid profile in carotid human atherosclerotic plaques is associated with a more inflammatory plaque phenotype and with future cardiovascular events (CE).
ĂConclusions: This work presents the first report on a human loss-of-
function mutation in OSBPL1A, which affects cholesterol efflux capacity associated with the low HDLc phenotype.
EAS16-0604, NOVEL PATHWAYS IN ATHEROSCLEROSIS. REDUCING AMYLOID PROCESSING PREVENTS DIABETES INDUCED VASCULAR DYSFUNCTION P. Meakin, F. Khan, M. Ashford. University of Dundee, Division of Cardiovascular & Diabetes Medicine, Dundee, United Kingdom Objectives: b-amyloid is produced via the cleavage of amyloid precursor protein (APP) by b-secretase (BACE1), resulting in the formation of amyloid plaques, a hallmark Alzheimer’s disease (AD) pathology. AD, type 2 diabetes and cardiovascular disease appear intimately linked with endothelial dysfunction, inflammation, insulin resistance and elevated b-amyloid levels all common features. Aims: Determine (1) the vascular expression profile of BACE1, (2) whether manipulating the production of b-amyloid in mice alters endothelial function. Methods: BACE1 immuno-histological staining was performed on human temporal and carotid arteries and mouse aortas. Measurements of blood pressure and endothelial function, determined by the vascular response to Acetylcholine using laser Doppler imaging, were made in wild-type
Methods: Carotid plaques (n¼159) from patients with and without cerebrovascular symptoms were analyzed for levels of 148 different lipids by electrospray ionization tandem mass spectrometry and phenotyped by measuring inflammatory mediators in homogenates and by immunhistochemical staining of sections. Results: By using 5 different clustering algorithms the lipid composition of each plaque was classified into two major clusters with different lipid profiles. Symptomatic plaques were significantly overrepresented in cluster 2 (76%, p<2.710-5), whereas cluster 1 contained more asymptomatic plaques (60%, p<2.710-5). In addition, cluster 2 was found to harbor more plaques with a high vulnerability index (CD68/ORO/GlycophorinA/Masson/a-Actin; 68%, p<1.210-9) as well as more inflammatory plaques (MCP-1/IL-6/IL-1b; 73%, p<1.310-10), whereas the opposite was true for cluster 1 regarding vulnerability and inflammatory score. In line with this, the levels of several chemokines, including RANTES and MIP1-a/ b were significantly higher in cluster 2 plaques. A reduced risk for future CE was found for cluster 1 (p<0.032). After adjusting for possible confounders (age, LDL, HDL, smoking, b-blockers, WBC and eGFR) the hazard ratio for future CE was 0.438 (p¼0.039). Adjusting for Framingham risk factors yielded similar results. Conclusions: These results indicate that the lipid composition of human atherosclerotic plaques is associated with a pro-inflammatory plaque phenotype and increased risk of future CE.
EAS16-1001, NOVEL PATHWAYS IN ATHEROSCLEROSIS. A COMPLEX ATHEROSCLEROTIC PHENOTYPE OF MIF GENE-DEFICIENT MICE IN AN ATHEROGENIC APOE-/- BACKGROUND UNCOVERS A NOVEL CONNECTION BETWEEN MIF AND B CELLS C. Schmitz 1, E. Straußfeld 1, O. El Bounkari 1, H. Noels 2, J. Bernhagen 1. 1 Institute for stroke and dementia ISD, Vascular Biology, €t LMU, Munich, Germany; 2 Institute for Ludwig-Maximilians-Universita Molecular Cardiovascular Research, RWTH-Aachen University, Aachen, Germany
EAS16-0030, INTRACELLULAR LIPID METABOLISM. CONVERGENT SIGNALING PATHWAYS CONTROLLED BY LRP1 CYTOPLASMIC AND EXTRACELLULAR DOMAINS LIMIT CELLULAR CHOLESTEROL ACCUMULATION P. Boucher 1, Z. El Asmar 1, J. Terrand 1, M. Jenty 1, L. Host 1, M. Mlih 1, A. Zerr 1, H. Justiniano 1, L. R. Matz 1, C. Boudier 1, E. Scholler 1, J.M. 3, C. Schaeffer 3, V.D. Alain 3, J. Garnier 2, D. Bertaccini 3, D. Thierse 4 1 Herz . UMR CNRS 7213, Physiology, Strasbourg Cedex, France; 2 Institut de G en etique et de Biologie Mol eculaire et Cellulaire, Stem Cell Department, etrie Strasbourg Cedex, France; 3 CNRS- UMR 7178, Laboratoire de Spectrom de Masse BioOrganique LSMBO, Strasbourg, France; 4 UT Southwestern Medical Center, Department of Molecular Genetics and Center for Translational Neurodegeneration Research, Dallas, TX, USA Objectives: The Low Density Lipoprotein (LDL) receptor-related protein 1 (LRP1) is a ubiquitously expressed cell surface receptor. We previously demonstrated that a LRP1/Wnt5a pathway limits cholesterol intracellular accumulation. However, the underlying mechanisms are unknown. Methods: We used cells and mice over expressing Wnt5a in adipose tissue to determine how LRP1 regulates Wnt5a, and how Wnt5a prevents intracellular cholesterol accumulation Results: Our data show that the extracellular (a) chain of LRP1 mediates TGFb-induced enhancement of Wnt5a which limits intracellular cholesterol accumulation by inhibiting cholesterol biosynthesis and by promoting cholesterol export. We moreover demonstrate that the cytoplasmic (b) chain of LRP1 suffices to limit cholesterol accumulation in LRP1-/- cells. Through binding of Erk2 to the second of its carboylterminal NPxY motifs, LRP1 b-chain positively regulates the expression of ABCA1 and of neutral cholesterol ester hydrolase (NCEH1). Conclusions: These results highlight unexpected functions of LRP1 and the canonical Wnt5a pathway, and new therapeutic potential in cholesterol-associated disorders, including cardiovascular diseases.
EAS16-0283, INTRACELLULAR LIPID METABOLISM. MONOGLYCERIDE LIPASE REGULATES ENDOCANNABINOID TONE AND ATHEROSCLEROTIC PLAQUE STRUCTURE IN APOLIPOPROTEIN EDEFICIENT MICE N. Vujic 1, S. Schlager 1, T.O. Eichmann 2, M. Goeritzer 1, C.T. MadreiterSokolowski 1, S. Schauer 3, A. Lass 2, R. Zimmermann 2, G. Hoefler 3, W.F. Graier 1, B. Radovic 1, D. Kratky 1. 1 Medical University of Graz, Institute of Molecular Biology and Biochemistry, Graz, Austria; 2 University of Graz, Institute of Molecular Biosciences, Graz, Austria; 3 Medical University of Graz, Institute of Pathology, Graz, Austria Objectives: Monoglyceride lipase (MGL) mediates the last step of lipolysis by hydrolyzing monoglyceride to glycerol and fatty acid. Among substrates for MGL activity is 2-arachidonoylglycerol (2-AG), the most abundant endocannabinoid in mammals. 2-AG acts as full agonist on cannabinoid receptors (CBR) 1 and 2, which are biphasically distributed in brain and immune cells, respectively. Based on the direct involvement of MGL in lipolysis and its indirect effects on endocannabinoid homeostasis and thus immune response, we hypothesized that MGL deficiency modulates CB2Rmediated signaling and atherogenesis. Methods: We generated apolipoprotein E/MGL double-knockout (DKO) mice, challenged them with western-type diet, and assessed atherogenesis. Results: We found systemically elevated 2-AG concentrations in DKO mice. Fasting plasma lipids were comparable between genotypes, however, DKO mice had reduced hepatic steatosis and delayed chylomicron secretion. DKO macrophages were able to fully respond to 2-AG stimulation, arguing against CB2R desensitization, and were resistant to foam cell formation. Although atherosclerotic plaque was enlarged in DKO mice, plaque composition showed reduced relative abundance of necrotic core and macrophages and elevated collagen content and
e259
fibrotic cap thickness, leading to the formation of stabilized lesions. Increased plaque collagen may be a consequence of higher relative abundance of smooth muscle cells within the lesions. Pharmacologic CB2R antagonism reversed atherosclerotic plaque structure, suggesting that the observed lesion phenotype is the consequence of potentiated CB2R signaling in DKO mice. Conclusions: Our results demonstrate that MGL deficiency strongly regulates endocannabinoid homeostasis and atherogenesis. Despite increased lesion size, elevated 2-AG concentrations have protective effects on plaque stability.
EAS16-0265, INTRACELLULAR LIPID METABOLISM. LACK OF ADIPOSE TISSUE LIPOLYSIS PROTECTS AGAINST PRESSURE OVERLOAD-INDUCED HEART FAILURE A. Foryst-Ludwig 1, J. Salatzki 1, S. Brix 1, Z. Ban 1, J. Grune 1, R. Klopfleisch 2, M. Rothe 3, E. Kershaw 4, U. Kintscher 1. 1 Institute of €tsmedizin Berlin, Berlin, Germany; Pharmacology, CCR, Charite-Universita 2 Institute of Veterinary Pathology, Freie Universitaet Berlin, Berlin, Germany; 3 Lipidomix, Lipidomix GmbH, Berlin, Germany; 4 Division of Endocrinology- Diabetes- and Metabolism, University of Pittsburgh, Pittsburgh, USA Objectives: Cardiac metabolism undergoes substantial changes in response to pathological hypertrophy (PH), characterized by decreased free fatty acid (FFA) oxidation and a loss of metabolic flexibility. In this study we investigated the impact of AT lipolysis, regulated by Adipose Triglyceride Lipase (ATGL) on the development of PH in a pressure overload-induced cardiac hypertrophy model in mice. Methods: AT-specific ATGL-deficient (atATGL-KO) and wild type mice (WT) underwent aortic constriction (TAC) or sham surgery. Echocardiographic analysis was performed 11 weeks after surgery. Left ventricular mass (LVM) and ejection fraction (EF%) were calculated. Insulin sensitivity was assessed by glucose and insulin tolerance test. FAs were measured in serum and FA serum profiling was performed using HPLC/MS technology. Results: Echocardiographic analysis revealed that LVM in WT were significantly higher compared to atATGL-KO after TAC. Moreover, WT-TAC animals showed significant reduction of EF ([%] WT: 28.81±6.9 atATGL-KO: 42.39±4.5; p<0.01). In line with those findings cardiac fibrosis, cardiac diameter and expression of beta-MyHC, a marker specific for PH, were markedly higher in WT-TAC than in atATGL-KO-TAC. Using serum FAprofiling we identified specific set of FAs, significantly reduced only in the serum of atATGL-KO-TAC mice. Importantly, atATGL-KO-TAC showed overall lower serum FFA-levels and higher insulin sensitivity when compared to WT-TAC. Conclusions: In this study, we demonstrate that atATGL is crucial for the development of pressure overload-induced PH. The lack of ATGL in adipose tissue, the associated reduced lipolysis/ altered serum lipid profile and the subsequent switch in cardiac metabolism from FFA oxidation to glycolysis are potential underlying mechanisms of this process.
EAS16-0731, INTRACELLULAR LIPID METABOLISM. A LOSS-OF-FUNCTION VARIANT IN OSBPL1A PREDISPOSES TO LOW PLASMA HDL CHOLESTEROL LEVELS AND IMPAIRED CHOLESTEROL EFFLUX CAPACITY J. van Capelleveen 1, J. Pirhonen 2, M.M. Motazacker 1, M. WeberBoyvat 3, M. Jauhiainen 4, G.K. Hovingh 1, G.M. Dallinga-Thie 1, V. Olkkonen 2. 1 Academic Medical Center, Vascular Medicine, Amsterdam, Netherlands; 2 Faculty of Medicine, University of Helsinki, Department of Anatomy, Helsinki, Finland; 3 Minerva foundation Institute for Medical Research, Minerva, Helsinki, Finland; 4 National Institute for Health and Welfare, Genomics and biomarkers unit, Helsinki, Finland Objectives: Oxysterol-binding protein-like (OSBPL) proteins have a function in cellular cholesterol homeostasis, however their specific contribution has not been elucidated in humans
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Abstracts / Atherosclerosis 252 (2016) e236ee264
Methods: In subjects with high-density-lipoprotein cholesterol (HDL-C) <1st percentile in the general population (n¼40) we sequenced the coding region of 195 lipid-related genes including OSBPL1A. Next, we investigated the composition and function of HDL from the carriers and non-carriers, the ability of skin fibroblasts to efflux cholesterol and studied the properties of the mutant protein in cultured HuH-7 cells. Results: We identified a heterozygous variant OSBPL1A p.C39X encoding a short truncated protein fragment, that co-segregated with low plasma HDL-C in a small pedigree. In line plasma apoA-I levels were lower in mutation carriers. Other HDL parameters were not different. Fibroblasts from a p.C39X carrier showed reduced cholesterol efflux potential to HDL and apoA-I, p<0.05, as well as lower OSBPL1A protein expression on western blot. Cholesterol efflux from labelled Raw264.7 macrophages to serum showed lower efflux capacity for serum derived from p.C39X carriers compared to family wildtype controls, p<0.01, but no difference was observed for efflux to isolated HDL. The OSBPL-39X protein did not colocalize to the endosomes confirming impaired functionality
(C57bl/6), APP over-expressing and BACE1 knockout (BACE1KO) mice fed either regular chow or high fat (HF) diet (45% fat) for 20 weeks to drive obesity and insulin resistance. Results: BACE1 protein is detectable in endothelial and smooth muscle cells in human and mouse arteries. HF-fed BACE1KO, compared to dietinduced obese wild-type (DIO), mice were protected from endothelial dysfunction (Ach AUC: BACE1KO 30163 ± 4339, DIO 18670 ± 1445; P< 0.01), and hypertension (P< 0.05). In contrast, APP over-expressing mice with increased tissue b-amyloid, exhibited impaired vascular responses (Ach AUC: APP 24289 ± 3444, WT 39805 ± 3309; P< 0.05), and worsened hypertension (P< 0.05) on regular chow, independent of body weight. Conclusions: We suggest that amyloid processing has a role in normal vascular function with aberrant processing leading to endothelial dysfunction and hypertension. Thus BACE1 inhibitors may be a novel treatment for diabetes-induced vascular disease.
EAS16-0697, NOVEL PATHWAYS IN ATHEROSCLEROSIS. A LIPID METABOLITE PROFILE IN ATHEROSCLEROTIC PLAQUES ASSOCIATED WITH INCREASED INFLAMMATION AND CARDIOVASCULAR RISK € rkbacka 1, A. Edsfeldt 1, A. Danielsson 2, M. Wigren 1, H. L. Tomas 1, H. Bjo Grufman 1, A. Persson 1, C. Prehn 3, J. Adamski 3, J. Nilsson 1, I. Gonçalves 1. 1 Experimental Cardiovascular Research Unit, Department of €, Sweden; 2 Molecular Metabolism, Department of Clinical Sciences, Malmo €, Sweden; 3 Institute of Experimental Genetics, Clinical Sciences, Malmo Helmholtz Center Munich, Munich, Germany Objectives: Atherosclerosis is characterized by the retention of lipids and chronic inflammation in the vasculature. In the present study we asked whether a certain lipid profile in carotid human atherosclerotic plaques is associated with a more inflammatory plaque phenotype and with future cardiovascular events (CE).
ĂConclusions: This work presents the first report on a human loss-of-
function mutation in OSBPL1A, which affects cholesterol efflux capacity associated with the low HDLc phenotype.
EAS16-0604, NOVEL PATHWAYS IN ATHEROSCLEROSIS. REDUCING AMYLOID PROCESSING PREVENTS DIABETES INDUCED VASCULAR DYSFUNCTION P. Meakin, F. Khan, M. Ashford. University of Dundee, Division of Cardiovascular & Diabetes Medicine, Dundee, United Kingdom Objectives: b-amyloid is produced via the cleavage of amyloid precursor protein (APP) by b-secretase (BACE1), resulting in the formation of amyloid plaques, a hallmark Alzheimer’s disease (AD) pathology. AD, type 2 diabetes and cardiovascular disease appear intimately linked with endothelial dysfunction, inflammation, insulin resistance and elevated b-amyloid levels all common features. Aims: Determine (1) the vascular expression profile of BACE1, (2) whether manipulating the production of b-amyloid in mice alters endothelial function. Methods: BACE1 immuno-histological staining was performed on human temporal and carotid arteries and mouse aortas. Measurements of blood pressure and endothelial function, determined by the vascular response to Acetylcholine using laser Doppler imaging, were made in wild-type
Methods: Carotid plaques (n¼159) from patients with and without cerebrovascular symptoms were analyzed for levels of 148 different lipids by electrospray ionization tandem mass spectrometry and phenotyped by measuring inflammatory mediators in homogenates and by immunhistochemical staining of sections. Results: By using 5 different clustering algorithms the lipid composition of each plaque was classified into two major clusters with different lipid profiles. Symptomatic plaques were significantly overrepresented in cluster 2 (76%, p<2.710-5), whereas cluster 1 contained more asymptomatic plaques (60%, p<2.710-5). In addition, cluster 2 was found to harbor more plaques with a high vulnerability index (CD68/ORO/GlycophorinA/Masson/a-Actin; 68%, p<1.210-9) as well as more inflammatory plaques (MCP-1/IL-6/IL-1b; 73%, p<1.310-10), whereas the opposite was true for cluster 1 regarding vulnerability and inflammatory score. In line with this, the levels of several chemokines, including RANTES and MIP1-a/ b were significantly higher in cluster 2 plaques. A reduced risk for future CE was found for cluster 1 (p<0.032). After adjusting for possible confounders (age, LDL, HDL, smoking, b-blockers, WBC and eGFR) the hazard ratio for future CE was 0.438 (p¼0.039). Adjusting for Framingham risk factors yielded similar results. Conclusions: These results indicate that the lipid composition of human atherosclerotic plaques is associated with a pro-inflammatory plaque phenotype and increased risk of future CE.
EAS16-1001, NOVEL PATHWAYS IN ATHEROSCLEROSIS. A COMPLEX ATHEROSCLEROTIC PHENOTYPE OF MIF GENE-DEFICIENT MICE IN AN ATHEROGENIC APOE-/- BACKGROUND UNCOVERS A NOVEL CONNECTION BETWEEN MIF AND B CELLS C. Schmitz 1, E. Straußfeld 1, O. El Bounkari 1, H. Noels 2, J. Bernhagen 1. 1 Institute for stroke and dementia ISD, Vascular Biology, €t LMU, Munich, Germany; 2 Institute for Ludwig-Maximilians-Universita Molecular Cardiovascular Research, RWTH-Aachen University, Aachen, Germany