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Yang J, Xu M, Wang Z, He M, Zhang G, Jin L, Zhao R, Pan Y, Tong J, Nie L. Unraveling Estrogen and PCSK9's Roles in Lipid Metabolism Disorders among Ovariectomized Mice. Reprod Sci 2024:10.1007/s43032-024-01614-8. [PMID: 38871967 DOI: 10.1007/s43032-024-01614-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/29/2024] [Indexed: 06/15/2024]
Abstract
We explore the interaction between estrogen and PCSK9 and their collective impact on lipid metabolism, especially concerning the regulation of low-density lipoprotein receptor levels. Utilizing both animal and cellular models, including ovariectomized mice and HepG2 cell lines, we demonstrate that estrogen deficiency leads to a disruption in lipid metabolism, characterized by elevated levels of total cholesterol and LDL-C. The study commences with mice undergoing ovariectomy, followed by a diet regimen comprising either high-fat diet or normal feed for a four-week duration. Key assessments include analyzing lipid metabolism, measuring PCSK9 levels in the bloodstream, and evaluating hepatic low-density lipoprotein receptor expression. We will also conduct correlation analyses to understand the relationship between PCSK9 and various lipid profiles. Further, a subset of ovariectomized mice on high-fat diet will undergo treatment with either estrogen or PCSK9 inhibitor for two weeks, with a subsequent re-evaluation of the earlier mentioned parameters. Our findings reveal that estrogen inhibits PCSK9-mediated degradation of low-density lipoprotein receptor, a process crucial for maintaining lipid homeostasis. Through a series of experiments, including immunohistochemistry and western blot analysis, we establish that PCSK9 is involved in lipid metabolism disorders caused by estrogen deficiency and that estrogen regulates PCSK9 and low-density lipoprotein receptor at post-transcriptional level. The study provides a mechanism for the involvement of PCSK9 in elucidating the disorders of lipid metabolism caused by estrogen deficiency due to perimenopause and ovarian decline.
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Affiliation(s)
- Jie Yang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Miaomiao Xu
- Department of Immunology, West China School of Basic Medical Sciences and Forensic Medicine, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Chengdu, China
| | - Zun Wang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Man He
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Gao Zhang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Lei Jin
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Rongqian Zhao
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Yiran Pan
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Jiyu Tong
- Department of Immunology, West China School of Basic Medical Sciences and Forensic Medicine, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Chengdu, China.
- West China, Second University Hospital, Sichuan University, Chengdu, China.
| | - Li Nie
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China.
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2
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Schmitt J, Poole E, Groves I, Owen DJ, Graham SC, Sinclair J, Kelly BT. Repurposing an endogenous degradation domain for antibody-mediated disposal of cell-surface proteins. EMBO Rep 2024; 25:951-970. [PMID: 38287192 PMCID: PMC10933360 DOI: 10.1038/s44319-024-00063-3] [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: 07/27/2023] [Revised: 12/14/2023] [Accepted: 12/21/2023] [Indexed: 01/31/2024] Open
Abstract
The exquisite specificity of antibodies can be harnessed to effect targeted degradation of membrane proteins. Here, we demonstrate targeted protein removal utilising a protein degradation domain derived from the endogenous human protein Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9). Recombinant antibodies genetically fused to this domain drive the degradation of membrane proteins that undergo constitutive internalisation and recycling, including the transferrin receptor and the human cytomegalovirus latency-associated protein US28. We term this approach PACTAC (PCSK9-Antibody Clearance-Targeting Chimeras).
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Affiliation(s)
- Janika Schmitt
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Hills Road, CB2 0SP, Cambridge, UK
- Faculty of Medicine, Charité Berlin, 10117, Berlin, Germany
- Faculty of Medicine, University of Heidelberg, 69210, Heidelberg, Germany
| | - Emma Poole
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Hills Road, CB2 0SP, Cambridge, UK
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Ian Groves
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Hills Road, CB2 0SP, Cambridge, UK
- Infection Biology, Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - David J Owen
- Cambridge Institute for Medical Research, Keith Peters Building, Hills Road, Cambridge, CB2 0XY, UK.
| | - Stephen C Graham
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
| | - John Sinclair
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Hills Road, CB2 0SP, Cambridge, UK.
| | - Bernard T Kelly
- Cambridge Institute for Medical Research, Keith Peters Building, Hills Road, Cambridge, CB2 0XY, UK.
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3
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Wang Y, Tinsley B, Spolitu S, Zadroga JA, Agarwal H, Sarecha AK, Ozcan L. Geranylgeranyl isoprenoids and hepatic Rap1a regulate basal and statin-induced expression of PCSK9. J Lipid Res 2024; 65:100515. [PMID: 38309417 PMCID: PMC10910342 DOI: 10.1016/j.jlr.2024.100515] [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: 10/26/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/05/2024] Open
Abstract
LDL-C lowering is the main goal of atherosclerotic cardiovascular disease prevention, and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition is now a validated therapeutic strategy that lowers serum LDL-C and reduces coronary events. Ironically, the most widely used medicine to lower cholesterol, statins, has been shown to increase circulating PCSK9 levels, which limits their efficacy. Here, we show that geranylgeranyl isoprenoids and hepatic Rap1a regulate both basal and statin-induced expression of PCSK9 and contribute to LDL-C homeostasis. Rap1a prenylation and activity is inhibited upon statin treatment, and statin-mediated PCSK9 induction is dependent on geranylgeranyl synthesis and hepatic Rap1a. Accordingly, treatment of mice with a small-molecule activator of Rap1a lowered PCSK9 protein and plasma cholesterol and inhibited statin-mediated PCSK9 induction in hepatocytes. The mechanism involves inhibition of the downstream RhoA-ROCK pathway and regulation of PCSK9 at the post-transcriptional level. These data further identify Rap1a as a novel regulator of PCSK9 protein and show that blocking Rap1a prenylation through lowering geranylgeranyl levels contributes to statin-mediated induction of PCSK9.
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Affiliation(s)
- Yating Wang
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA; Department of Cardiology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Brea Tinsley
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Stefano Spolitu
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - John A Zadroga
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Heena Agarwal
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Amesh K Sarecha
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Lale Ozcan
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.
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4
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Liu MH, Lin XL, Xiao LL. SARS-CoV-2 nucleocapsid protein promotes TMAO-induced NLRP3 inflammasome activation by SCAP-SREBP signaling pathway. Tissue Cell 2024; 86:102276. [PMID: 37979395 DOI: 10.1016/j.tice.2023.102276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 11/12/2023] [Accepted: 11/12/2023] [Indexed: 11/20/2023]
Abstract
The sterol regulatory element-binding protein (SREBP) activation and cytokine level were significantly increased in coronavirus disease-19. The NLRP3 inflammasome is an amplifier for cellular inflammation. This study aimed to elucidate the modulatory effect of SARS-CoV-2 nucleocapsid protein (SARS-CoV-2 NP) on trimethylamine N-oxide (TMAO)-induced lipogenesis and NLRP3 inflammasome activation and the underlying mechanisms in vascular smooth muscle cells (VSMCs). Our data indicated that SARS-CoV-2 NP activates the dissociation of the SREBP cleavage activating protein (SCAP) from the endoplasmic reticulum, resulting in SREBP activation, increased lipogenic gene expression, and NLRP3 inflammasome activation. TMAO was applied to VSMC-induced NLRP3 inflammasome by promoting the SCAP-SREBP complex endoplasmic reticulum-to-Golgi translocation, which facilitates directly binding of SARS-CoV-2 NP to the NLRP3 protein for NLRP3 inflammasome assembly. SARS-CoV-2 NP amplified the TMAO-induced lipogenic gene expression and NLRP3 inflammasome. Knockdown of SCAP-SREBP2 can effectively reduce lipogenic gene expression and alleviate NLRP3 inflammasome-mediated systemic inflammation in VSMCs stimulated with TMAO and SARS-CoV-2 NP. These results reveal that SARS-CoV-2 NP amplified TMAO-induced lipogenesis and NLRP3 inflammasome activation via priming the SCAP-SREBP signaling pathway.
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Affiliation(s)
- Mi-Hua Liu
- Department of Clinical Laboratory, The Affiliated Ganzhou Hospital of Nanchang University, Ganzhou, Jiangxi 341000, People's Republic of China.
| | - Xiao-Long Lin
- Department of Pathology, Hui Zhou Third People's Hospital, Guangzhou Medical University, Huizhou City, Guangdong 516002, People's Republic of China
| | - Le-Le Xiao
- Intensive Care Unit, The Affiliated Ganzhou Hospital of Nanchang University, Ganzhou, Jiangxi 341000, People's Republic of China.
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Agnello F, Mauro MS, Rochira C, Landolina D, Finocchiaro S, Greco A, Ammirabile N, Raffo C, Mazzone PM, Spagnolo M, Occhipinti G, Imbesi A, Giacoppo D, Capodanno D. PCSK9 inhibitors: current status and emerging frontiers in lipid control. Expert Rev Cardiovasc Ther 2024; 22:41-58. [PMID: 37996219 DOI: 10.1080/14779072.2023.2288169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 11/22/2023] [Indexed: 11/25/2023]
Abstract
INTRODUCTION Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of global mortality, imposing substantial healthcare economic burdens. Among the modifiable risk factors, hypercholesterolemia, especially elevated low-density lipoprotein cholesterol (LDL-C), plays a pivotal role in ASCVD development. Novel therapies such as PCSK9 (Proprotein Convertase Subtilisin/Kexin type 9) inhibitors are emerging to address this concern. These inhibitors offer the potential to reduce ASCVD risk by directly targeting LDL-C levels. AREAS COVERED The article reviews the structural and functional aspects of PCSK9, highlighting its role in LDL receptor regulation. The pharmacological strategies for PCSK9 inhibition, including monoclonal antibodies, binding peptides, gene silencing, and active immunization, are explored. Clinical evidence from various trials underscores the safety and efficacy of PCSK9 inhibitors in reducing LDL-C levels and potentially improving cardiovascular outcomes. Despite these promising results, challenges such as cost-effectiveness and long-term safety considerations are addressed. EXPERT OPINION Among PCSK9 inhibitors, monoclonal antibodies represent a cornerstone. Many trials have showed their efficacy in reducing LDL-C and the risk for major adverse clinical events, revealing long-lasting effects, with special benefits particularly for statin-intolerant and familial hypercholesterolemia patients. However, long-term impacts, high costs, and patient selection necessitate further research.
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Affiliation(s)
- Federica Agnello
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Maria Sara Mauro
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Carla Rochira
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Davide Landolina
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Simone Finocchiaro
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Antonio Greco
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Nicola Ammirabile
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Carmelo Raffo
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Placido Maria Mazzone
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Marco Spagnolo
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Giovanni Occhipinti
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Antonino Imbesi
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Daniele Giacoppo
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
| | - Davide Capodanno
- Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico "G. Rodolico - San Marco", University of Catania, Catania, Italy
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6
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Srivastava RAK. New opportunities in the management and treatment of refractory hypercholesterolemia using in vivo CRISPR-mediated genome/base editing. Nutr Metab Cardiovasc Dis 2023; 33:2317-2325. [PMID: 37805309 DOI: 10.1016/j.numecd.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/07/2023] [Accepted: 08/10/2023] [Indexed: 10/09/2023]
Abstract
AIMS Refractory hypercholesterolemia (RH), caused primarily by the loss-of-function mutation of LDL receptor (LDLR) gene seen in HoFH and HeFH patients, remains a major risk factor for atherosclerotic cardiovascular disease (ASCVD). Statin and ezetimibe combination therapy lower circulating LDL by 30% in HoFH patients. PCSK9 mAB, being an LDLR-dependent therapy, is not effective in HoFH, but lowers LDL by 25% in HeFH patients. A maximum reduction of 50% was noted in HoFH patients treated with ANGPTL3 mAB, which was not enough to achieve therapeutic goal of LDL. Therefore, new approaches are warranted to offer hopes to individuals intolerant to higher dose statins and not able to achieve recommended LDL level. DATA SYNTHESIS New approaches to lower LDL include gene therapy and gene editing. AAV-based gene therapy has shown encouraging results in animal models. Using CRISPR/Cas9-mediated genome/base editing, gain of function and loss of function have been successfully done in animal models. Recent progress in the refinement of genome/base editing has overcome the issues of off-target mutagenesis with ∼1% mutagenesis in case of PCSK9 and almost no off-target mutagenesis in inactivating ANGPTL3 in animal models showing 50% reduction in cholesterol. Current approaches using CRISPR-Cas9 genome/base editing targeting LDLR-dependent and LDLR-independent pathways are underway. CONCLUSIONS The new information on gain of LDLR function and inactivation of ANGPTL3 together with developments in genome/base editing technology to overcome off-target insertion and deletion mutagenesis offer hope to refractory hypercholesterolemic individuals who are at a higher risk of developing ASCVD.
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7
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Wang Y, Tinsley B, Spolitu S, Zadroga JA, Agarwal H, Sarecha AK, Ozcan L. Geranylgeranyl Isoprenoids and Hepatic Rap1a Regulate Basal and Statin-Induced Expression of PCSK9. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563509. [PMID: 37961667 PMCID: PMC10634727 DOI: 10.1101/2023.10.23.563509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Low-density lipoprotein cholesterol (LDL-C) lowering is the main goal of atherosclerotic cardiovascular disease prevention, and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition is now a validated therapeutic strategy that lowers serum LDL-C and reduces coronary events. Ironically, the most widely used medicine to lower cholesterol, statins, has been shown to increase circulating PCSK9 levels, which limits their efficacy. Here, we show that geranylgeranyl isoprenoids and hepatic Rap1a regulate both basal and statin induced expression of PCSK9 and contribute to LDL-C homeostasis. Rap1a prenylation and activity is inhibited upon statin treatment, and statin mediated PCSK9 induction is dependent on geranylgeranyl synthesis and hepatic Rap1a. Accordingly, treatment of mice with a small molecule activator of Rap1a lowered PCSK9 protein and plasma cholesterol and inhibited statin mediated PCSK9 induction in hepatocytes. The mechanism involves inhibition of the downstream RhoA-ROCK pathway and regulation of PCSK9 at the post transcriptional level. These data further identify Rap1a as a novel regulator of PCSK9 protein and show that blocking Rap1a prenylation through lowering geranylgeranyl levels contributes to statin-mediated induction of PCSK9.
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8
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Skeby CK, Hummelgaard S, Gustafsen C, Petrillo F, Frederiksen KP, Olsen D, Kristensen T, Ivarsen P, Madsen P, Christensen EI, Nielsen R, Birn H, Glerup S, Weyer K. Proprotein convertase subtilisin/kexin type 9 targets megalin in the kidney proximal tubule and aggravates proteinuria in nephrotic syndrome. Kidney Int 2023; 104:754-768. [PMID: 37406929 DOI: 10.1016/j.kint.2023.06.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 06/04/2023] [Accepted: 06/09/2023] [Indexed: 07/07/2023]
Abstract
Proteinuria is a prominent feature of chronic kidney disease. Interventions that reduce proteinuria slow the progression of chronic kidney disease and the associated risk of cardiovascular disease. Here, we propose a mechanistic coupling between proteinuria and proprotein convertase subtilisin/kexin type 9 (PCSK9), a regulator of cholesterol and a therapeutic target in cardiovascular disease. PCSK9 undergoes glomerular filtration and is captured by megalin, the receptor responsible for driving protein reabsorption in the proximal tubule. Accordingly, megalin-deficient mice and patients carrying megalin pathogenic variants (Donnai Barrow syndrome) were characterized by elevated urinary PCSK9 excretion. Interestingly, PCSK9 knockout mice displayed increased kidney megalin while PCSK9 overexpression resulted in its reduction. Furthermore, PCSK9 promoted trafficking of megalin to lysosomes in cultured proximal tubule cells, suggesting that PCSK9 is a negative regulator of megalin. This effect can be accelerated under disease conditions since either genetic destruction of the glomerular filtration barrier in podocin knockout mice or minimal change disease (a common cause of nephrotic syndrome) in patients resulted in enhanced tubular PCSK9 uptake and urinary PCSK9 excretion. Pharmacological PCSK9 inhibition increased kidney megalin while reducing urinary albumin excretion in nephrotic mice. Thus, glomerular damage increases filtration of PCSK9 and concomitantly megalin degradation, resulting in escalated proteinuria.
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Affiliation(s)
- Cecilie K Skeby
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Camilla Gustafsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Draupnir Bio, INCUBA Skejby, Aarhus, Denmark
| | | | | | - Ditte Olsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Draupnir Bio, INCUBA Skejby, Aarhus, Denmark
| | - Tilde Kristensen
- Department of Internal Medicine, Renal Unit, Regional Hospital Viborg, Viborg, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Per Ivarsen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Peder Madsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Draupnir Bio, INCUBA Skejby, Aarhus, Denmark
| | | | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Henrik Birn
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Simon Glerup
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Draupnir Bio, INCUBA Skejby, Aarhus, Denmark
| | - Kathrin Weyer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
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9
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Morales SV, Mahmood A, Pollard J, Mayne J, Figeys D, Wiseman PW. The LDL receptor is regulated by membrane cholesterol as revealed by fluorescence fluctuation analysis. Biophys J 2023; 122:3783-3797. [PMID: 37559362 PMCID: PMC10541495 DOI: 10.1016/j.bpj.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/17/2023] [Accepted: 08/07/2023] [Indexed: 08/11/2023] Open
Abstract
Membrane cholesterol-rich domains have been shown to be important for regulating a range of membrane protein activities. Low-density lipoprotein receptor (LDLR)-mediated internalization of cholesterol-rich LDL particles is tightly regulated by feedback mechanisms involving intracellular sterol sensors. Since LDLR plays a role in maintaining cellular cholesterol homeostasis, we explore the role that membrane domains may have in regulating LDLR activity. We expressed a fluorescent LDLR-mEGFP construct in HEK293T cells and imaged the unligated receptor or bound to an LDL/DiI fluorescent ligand using total internal reflection fluorescence microscopy. We studied the receptor's spatiotemporal dynamics using fluorescence fluctuation analysis methods. Image cross correlation spectroscopy reveals a lower LDL-to-LDLR binding fraction when membrane cholesterol concentrations are augmented using cholesterol esterase, and a higher binding fraction when the cells are treated with methyl-β-cyclodextrin) to lower membrane cholesterol. This suggests that LDLR's ability to metabolize LDL particles is negatively correlated to membrane cholesterol concentrations. We then tested if a change in activity is accompanied by a change in membrane localization. Image mean-square displacement analysis reveals that unligated LDLR-mEGFP and ligated LDLR-mEGFP/LDL-DiI constructs are transiently confined on the cell membrane, and the size of their confinement domains increases with augmented cholesterol concentrations. Receptor diffusion within the domains and their domain-escape probabilities decrease upon treatment with methyl-β-cyclodextrin, consistent with a change in receptor populations to more confined domains, likely clathrin-coated pits. We propose a feedback model to account for regulation of LDLR within the cell membrane: when membrane cholesterol concentrations are high, LDLR is sequestered in cholesterol-rich domains. These LDLR populations are attenuated in their efficacy to bind and internalize LDL. However, when membrane cholesterol levels drop, LDL has a higher binding affinity to its receptor and the LDLR transits to nascent clathrin-coated domains, where it diffuses at a slower rate while awaiting internalization.
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Affiliation(s)
- Sebastian V Morales
- Department of Chemistry, Faculty of Science, McGill University, Montreal, Canada
| | - Ahmad Mahmood
- Department of Physics, Faculty of Science, McGill University, Montreal, Canada
| | - Jacob Pollard
- Department of Chemistry, Faculty of Science, McGill University, Montreal, Canada
| | - Janice Mayne
- School of Pharmaceutical Sciences, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Daniel Figeys
- School of Pharmaceutical Sciences, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Paul W Wiseman
- Department of Chemistry, Faculty of Science, McGill University, Montreal, Canada; Department of Physics, Faculty of Science, McGill University, Montreal, Canada.
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10
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Hummelgaard S, Vilstrup JP, Gustafsen C, Glerup S, Weyer K. Targeting PCSK9 to tackle cardiovascular disease. Pharmacol Ther 2023; 249:108480. [PMID: 37331523 DOI: 10.1016/j.pharmthera.2023.108480] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/07/2023] [Accepted: 06/14/2023] [Indexed: 06/20/2023]
Abstract
Lowering blood cholesterol levels efficiently reduces the risk of developing atherosclerotic cardiovascular disease (ASCVD), including coronary artery disease (CAD), which is the main cause of death worldwide. CAD is caused by plaque formation, comprising cholesterol deposits in the coronary arteries. Proprotein convertase subtilisin kexin/type 9 (PCSK9) was discovered in the early 2000s and later identified as a key regulator of cholesterol metabolism. PCSK9 induces lysosomal degradation of the low-density lipoprotein (LDL) receptor in the liver, which is responsible for clearing LDL-cholesterol (LDL-C) from the circulation. Accordingly, gain-of-function PCSK9 mutations are causative of familial hypercholesterolemia, a severe condition with extremely high plasma cholesterol levels and increased ASCVD risk, whereas loss-of-function PCSK9 mutations are associated with very low LDL-C levels and protection against CAD. Since the discovery of PCSK9, extensive investigations in developing PCSK9 targeting therapies have been performed. The combined delineation of clear biology, genetic risk variants, and PCSK9 crystal structures have been major drivers in developing antagonistic molecules. Today, two antibody-based PCSK9 inhibitors have successfully progressed to clinical application and shown to be effective in reducing cholesterol levels and mitigating the risk of ASCVD events, including myocardial infarction, stroke, and death, without any major adverse effects. A third siRNA-based inhibitor has been FDA-approved but awaits cardiovascular outcome data. In this review, we outline the PCSK9 biology, focusing on the structure and nonsynonymous mutations reported in the PCSK9 gene and elaborate on PCSK9-lowering strategies under development. Finally, we discuss future perspectives with PCSK9 inhibition in other severe disorders beyond cardiovascular disease.
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Affiliation(s)
| | | | | | - Simon Glerup
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Draupnir Bio, INCUBA Skejby, Aarhus, Denmark
| | - Kathrin Weyer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
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11
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Srivastava RAK. A Review of Progress on Targeting LDL Receptor-Dependent and -Independent Pathways for the Treatment of Hypercholesterolemia, a Major Risk Factor of ASCVD. Cells 2023; 12:1648. [PMID: 37371118 DOI: 10.3390/cells12121648] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
Since the discovery of the LDL receptor in 1973 by Brown and Goldstein as a causative protein in hypercholesterolemia, tremendous amounts of effort have gone into finding ways to manage high LDL cholesterol in familial hypercholesterolemic (HoFH and HeFH) individuals with loss-of-function mutations in the LDL receptor (LDLR) gene. Statins proved to be the first blockbuster drug, helping both HoFH and HeFH individuals by inhibiting the cholesterol synthesis pathway rate-limiting enzyme HMG-CoA reductase and inducing the LDL receptor. However, statins could not achieve the therapeutic goal of LDL. Other therapies targeting LDLR include PCSK9, which lowers LDLR by promoting LDLR degradation. Inducible degrader of LDLR (IDOL) also controls the LDLR protein, but an IDOL-based therapy is yet to be developed. Among the LDLR-independent pathways, such as angiopoietin-like 3 (ANGPTL3), apolipoprotein (apo) B, apoC-III and CETP, only ANGPTL3 offers the advantage of treating both HoFH and HeFH patients and showing relatively better preclinical and clinical efficacy in animal models and hypercholesterolemic individuals, respectively. While loss-of-LDLR-function mutations have been known for decades, gain-of-LDLR-function mutations have recently been identified in some individuals. The new information on gain of LDLR function, together with CRISPR-Cas9 genome/base editing technology to target LDLR and ANGPTL3, offers promise to HoFH and HeFH individuals who are at a higher risk of developing atherosclerotic cardiovascular disease (ASCVD).
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Affiliation(s)
- Rai Ajit K Srivastava
- Integrated Pharma Solutions LLC, Boston, MA 02101-02117, USA
- College of Professional Studies, Northeastern University, Boston, MA 02101-02117, USA
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12
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Zhou YX, Wei J, Deng G, Hu A, Sun PY, Zhao X, Song BL, Luo J. Delivery of low-density lipoprotein from endocytic carriers to mitochondria supports steroidogenesis. Nat Cell Biol 2023:10.1038/s41556-023-01160-6. [PMID: 37277481 DOI: 10.1038/s41556-023-01160-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 05/01/2023] [Indexed: 06/07/2023]
Abstract
The low-density lipoprotein (LDL) is a major cholesterol carrier in circulation and is internalized into cells through LDL receptor (LDLR)-mediated endocytosis. The LDLR protein is highly expressed in the steroidogenic organs and LDL cholesterol is an important source for steroidogenesis. Cholesterol must be transported into the mitochondria, where steroid hormone biosynthesis initiates. However, how LDL cholesterol is conveyed to the mitochondria is poorly defined. Here, through genome-wide small hairpin RNA screening, we find that the outer mitochondrial membrane protein phospholipase D6 (PLD6), which hydrolyses cardiolipin to phosphatidic acid, accelerates LDLR degradation. PLD6 promotes the entrance of LDL and LDLR into the mitochondria, where LDLR is degraded by mitochondrial proteases and LDL-carried cholesterol is used for steroid hormone biosynthesis. Mechanistically, the outer mitochondrial membrane protein CISD2 binds to the cytosolic tail of LDLR and tethers LDLR+ vesicles to the mitochondria. The fusogenic lipid phosphatidic acid generated by PLD6 facilitates the membrane fusion of LDLR+ vesicles with the mitochondria. This intracellular transport pathway of LDL-LDLR bypasses the lysosomes and delivers cholesterol to the mitochondria for steroidogenesis.
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Affiliation(s)
- Yu-Xia Zhou
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Jian Wei
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Gang Deng
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Ao Hu
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Pu-Yu Sun
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Xiaolu Zhao
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Bao-Liang Song
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China.
| | - Jie Luo
- College of Life Sciences, Hubei Key Laboratory of Cell Homeostasis, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China.
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13
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Clifford BL, Jarrett KE, Cheng J, Cheng A, Seldin M, Morand P, Lee R, Chen M, Baldan A, de Aguiar Vallim TQ, Tarling EJ. RNF130 Regulates LDLR Availability and Plasma LDL Cholesterol Levels. Circ Res 2023; 132:849-863. [PMID: 36876496 PMCID: PMC10065965 DOI: 10.1161/circresaha.122.321938] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 02/23/2023] [Indexed: 03/07/2023]
Abstract
BACKGROUND Removal of circulating plasma low-density lipoprotein cholesterol (LDL-C) by the liver relies on efficient endocytosis and intracellular vesicle trafficking. Increasing the availability of hepatic LDL receptors (LDLRs) remains a major clinical target for reducing LDL-C levels. Here, we describe a novel role for RNF130 (ring finger containing protein 130) in regulating plasma membrane availability of LDLR. METHODS We performed a combination of gain-of-function and loss-of-function experiments to determine the effect of RNF130 on LDL-C and LDLR recycling. We overexpressed RNF130 and a nonfunctional mutant RNF130 in vivo and measured plasma LDL-C and hepatic LDLR protein levels. We performed in vitro ubiquitination assays and immunohistochemical staining to measure levels and cellular distribution of LDLR. We supplement these experiments with 3 separate in vivo models of RNF130 loss-of-function where we disrupted Rnf130 using either ASO (antisense oligonucleotides), germline deletion, or AAV CRISPR (adeno-associated virus clustered regularly interspaced short palindromic repeats) and measured hepatic LDLR and plasma LDL-C. RESULTS We demonstrate that RNF130 is an E3 ubiquitin ligase that ubiquitinates LDLR resulting in redistribution of the receptor away from the plasma membrane. Overexpression of RNF130 decreases hepatic LDLR and increases plasma LDL-C levels. Further, in vitro ubiquitination assays demonstrate RNF130-dependent regulation of LDLR abundance at the plasma membrane. Finally, in vivo disruption of Rnf130 using ASO, germline deletion, or AAV CRISPR results in increased hepatic LDLR abundance and availability and decreased plasma LDL-C levels. CONCLUSIONS Our studies identify RNF130 as a novel posttranslational regulator of LDL-C levels via modulation of LDLR availability, thus providing important insight into the complex regulation of hepatic LDLR protein levels.
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Affiliation(s)
- Bethan L. Clifford
- Department of Medicine, Division of Cardiology, University of California Los Angeles, CA, USA
| | - Kelsey E. Jarrett
- Department of Medicine, Division of Cardiology, University of California Los Angeles, CA, USA
| | - Joan Cheng
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
| | - Angela Cheng
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
| | - Marcus Seldin
- Department of Biological Chemistry, University of California Irvine, CA, USA
| | - Pauline Morand
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
| | | | - Mary Chen
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, MO, USA
| | - Angel Baldan
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, MO, USA
| | - Thomas Q. de Aguiar Vallim
- Department of Medicine, Division of Cardiology, University of California Los Angeles, CA, USA
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
| | - Elizabeth J. Tarling
- Department of Medicine, Division of Cardiology, University of California Los Angeles, CA, USA
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA, USA
- Lead contact
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14
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Bansal N, Kumar S, Brar PC. Update on management of paediatric dyslipidaemia. Curr Opin Endocrinol Diabetes Obes 2023; 30:52-64. [PMID: 36541082 DOI: 10.1097/med.0000000000000794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW Atherosclerosis and associated cardiovascular risk factors originate in childhood; hence, early management of dyslipidaemia is vital. However, hypercholesterolemia remains untreated or undertreated in many youths. We review current therapies, drugs under investigation and consider potential future directions for the management of paediatric dyslipidaemia to highlight the recent evidence and new therapeutic options for future use. RECENT FINDINGS Cardiovascular disease (CVD) risk factors in childhood, including dyslipidaemia, are associated with CVD risk and clinical CVD events in adulthood. Recent data show that initiation of statin therapy in childhood in children with familial hypercholesterolemia reduces the risk of CVD in adulthood. Several well tolerated and efficacious treatment options have become available in recent times for the management of dyslipidaemia in youth. Many new lipid-lowering drugs are under investigation to widen the available choices. Some of these drugs are now available for use in paediatrics, while some remain targets for future use. SUMMARY We review available treatment options for paediatric dyslipidaemia management, discuss potential limitations and propose future directions. We also acknowledge the need for continued research in paediatrics for optimal paediatric dyslipidaemia management.
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Affiliation(s)
- Nidhi Bansal
- Division of Pediatric Endocrinology, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas
| | - Seema Kumar
- Division of Pediatric Endocrinology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | - Preneet Cheema Brar
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, New York University Grossman School of Medicine, New York, New York, USA
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15
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Lebeau PF, Byun JH, Platko K, Saliba P, Sguazzin M, MacDonald ME, Paré G, Steinberg GR, Janssen LJ, Igdoura SA, Tarnopolsky MA, Wayne Chen SR, Seidah NG, Magolan J, Austin RC. Caffeine blocks SREBP2-induced hepatic PCSK9 expression to enhance LDLR-mediated cholesterol clearance. Nat Commun 2022; 13:770. [PMID: 35140212 PMCID: PMC8828868 DOI: 10.1038/s41467-022-28240-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 01/05/2022] [Indexed: 01/06/2023] Open
Abstract
Evidence suggests that caffeine (CF) reduces cardiovascular disease (CVD) risk. However, the mechanism by which this occurs has not yet been uncovered. Here, we investigated the effect of CF on the expression of two bona fide regulators of circulating low-density lipoprotein cholesterol (LDLc) levels; the proprotein convertase subtilisin/kexin type 9 (PCSK9) and the low-density lipoprotein receptor (LDLR). Following the observation that CF reduced circulating PCSK9 levels and increased hepatic LDLR expression, additional CF-derived analogs with increased potency for PCSK9 inhibition compared to CF itself were developed. The PCSK9-lowering effect of CF was subsequently confirmed in a cohort of healthy volunteers. Mechanistically, we demonstrate that CF increases hepatic endoplasmic reticulum (ER) Ca2+ levels to block transcriptional activation of the sterol regulatory element-binding protein 2 (SREBP2) responsible for the regulation of PCSK9, thereby increasing the expression of the LDLR and clearance of LDLc. Our findings highlight ER Ca2+ as a master regulator of cholesterol metabolism and identify a mechanism by which CF may protect against CVD.
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Affiliation(s)
- Paul F Lebeau
- Department of Medicine, Division of Nephrology, McMaster University, The Research Institute of St. Joe's Hamilton and the Hamilton Center for Kidney Research, Hamilton, ON, L8N 4A6, Canada
| | - Jae Hyun Byun
- Department of Medicine, Division of Nephrology, McMaster University, The Research Institute of St. Joe's Hamilton and the Hamilton Center for Kidney Research, Hamilton, ON, L8N 4A6, Canada
| | - Khrystyna Platko
- Department of Medicine, Division of Nephrology, McMaster University, The Research Institute of St. Joe's Hamilton and the Hamilton Center for Kidney Research, Hamilton, ON, L8N 4A6, Canada
| | - Paul Saliba
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Matthew Sguazzin
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Melissa E MacDonald
- Department of Medicine, Division of Nephrology, McMaster University, The Research Institute of St. Joe's Hamilton and the Hamilton Center for Kidney Research, Hamilton, ON, L8N 4A6, Canada
| | - Guillaume Paré
- Population Health Research Institute, McMaster University, Hamilton, ON, L8L 2X2, Canada.,The Departments of Medicine, Epidemiology and Pathology, McMaster University, Hamilton, ON, L8L 2X2, Canada.,The Thrombosis and Atherosclerosis Research Institute (TaARI), Department of Medicine, David Braley Research Institute, McMaster University, Hamilton, L8L 2X2, Canada
| | - Gregory R Steinberg
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8S 4L8, Canada.,Centre for Metabolism, Obesity and Diabetes Research, Department of Medicine, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Luke J Janssen
- Firestone Institute for Respiratory Health, St. Joseph's Hospital, Hamilton, ON, L8S 4K1, Canada
| | - Suleiman A Igdoura
- Department of Biology and Pathology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Mark A Tarnopolsky
- Department of Medicine/Neurology, McMaster University, Hamilton, ON, L8N 3Z5, Canada.,Department of Pediatrics, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - S R Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 2T9, Canada
| | - Nabil G Seidah
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, affiliated to the University of Montreal, Montreal, QC, H2W 1R7, Canada
| | - Jakob Magolan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Richard C Austin
- Department of Medicine, Division of Nephrology, McMaster University, The Research Institute of St. Joe's Hamilton and the Hamilton Center for Kidney Research, Hamilton, ON, L8N 4A6, Canada. .,The Thrombosis and Atherosclerosis Research Institute (TaARI), Department of Medicine, David Braley Research Institute, McMaster University, Hamilton, L8L 2X2, Canada.
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16
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Xia XD, Peng ZS, Gu HM, Wang M, Wang GQ, Zhang DW. Regulation of PCSK9 Expression and Function: Mechanisms and Therapeutic Implications. Front Cardiovasc Med 2021; 8:764038. [PMID: 34782856 PMCID: PMC8589637 DOI: 10.3389/fcvm.2021.764038] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/16/2021] [Indexed: 12/25/2022] Open
Abstract
Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes degradation of low-density lipoprotein receptor (LDLR) and plays a central role in regulating plasma levels of LDL cholesterol levels, lipoprotein(a) and triglyceride-rich lipoproteins, increasing the risk of cardiovascular disease. Additionally, PCSK9 promotes degradation of major histocompatibility protein class I and reduces intratumoral infiltration of cytotoxic T cells. Inhibition of PCSK9 increases expression of LDLR, thereby reducing plasma levels of lipoproteins and the risk of cardiovascular disease. PCSK9 inhibition also increases cell surface levels of major histocompatibility protein class I in cancer cells and suppresses tumor growth. Therefore, PCSK9 plays a vital role in the pathogenesis of cardiovascular disease and cancer, the top two causes of morbidity and mortality worldwide. Monoclonal anti-PCSK9 antibody-based therapy is currently the only available treatment that can effectively reduce plasma LDL-C levels and suppress tumor growth. However, high expenses limit their widespread use. PCSK9 promotes lysosomal degradation of its substrates, but the detailed molecular mechanism by which PCSK9 promotes degradation of its substrates is not completely understood, impeding the development of more cost-effective alternative strategies to inhibit PCSK9. Here, we review our current understanding of PCSK9 and focus on the regulation of its expression and functions.
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Affiliation(s)
- Xiao-Dan Xia
- Department of Orthopedics, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Zhong-Sheng Peng
- School of Economics, Management and Law, University of South China, Hengyang, China
| | - Hong-Mei Gu
- Group on the Molecular and Cell Biology of Lipids, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Maggie Wang
- Group on the Molecular and Cell Biology of Lipids, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Gui-Qing Wang
- Department of Orthopedics, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Da-Wei Zhang
- Group on the Molecular and Cell Biology of Lipids, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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17
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Evaluating Targeted Therapies in Ovarian Cancer Metabolism: Novel Role for PCSK9 and Second Generation mTOR Inhibitors. Cancers (Basel) 2021; 13:cancers13153727. [PMID: 34359627 PMCID: PMC8345177 DOI: 10.3390/cancers13153727] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/15/2021] [Accepted: 07/20/2021] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Dysregulated lipid metabolism is emerging as a hallmark in several malignancies, including ovarian cancer (OC). Specifically, metastatic OC is highly dependent on lipid-rich omentum. We aimed to investigate the therapeutic value of targeting lipid metabolism in OC. For this purpose, we studied the role of PCSK9, a cholesterol-regulating enzyme, in OC cell survival and its downstream signaling. We also investigated the cytotoxic efficacy of a small library of metabolic (n = 11) and mTOR (n = 10) inhibitors using OC cell lines (n = 8) and ex vivo patient-derived cell cultures (PDCs, n = 5) to identify clinically suitable drug vulnerabilities. Targeting PCSK9 expression with siRNA or PCSK9 specific inhibitor (PF-06446846) impaired OC cell survival. In addition, overexpression of PCSK9 induced robust AKT phosphorylation along with increased expression of ERK1/2 and MEK1/2, suggesting a pro-survival role of PCSK9 in OC cells. Moreover, our drug testing revealed marked differences in cytotoxic responses to drugs targeting metabolic pathways of high-grade serous ovarian cancer (HGSOC) and low-grade serous ovarian cancer (LGSOC) PDCs. Our results show that targeting PCSK9 expression could impair OC cell survival, which warrants further investigation to address the dependency of this cancer on lipogenesis and omental metastasis. Moreover, the differences in metabolic gene expression and drug responses of OC PDCs indicate the existence of a metabolic heterogeneity within OC subtypes, which should be further explored for therapeutic improvements.
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18
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He B, Kang S, Chen Z, Liu X, Wang J, Li X, Liu X, Zheng L, Luo M, Wang Y. Hypercholesterolemia risk associated Abca6 does not regulate lipoprotein metabolism in mice or hamster. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159006. [PMID: 34274505 DOI: 10.1016/j.bbalip.2021.159006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 12/14/2022]
Abstract
Hypercholesterolemia has strong heritability and about 40-60% of hypercholesterolemia is caused by genetic risk factors. A number of monogenic genes have been identified so far for familial hypercholesterolemia (FH). However, in the general population, more than 90% of individuals with LDL cholesterol over 190 mg/dL do not carry known FH mutations. Large scale whole-exome sequencing has identified thousands of variants that are predicted to be loss-of-function (LoF) and each individual has a median of about twenty rare LoF variants and several hundreds more common LoF variants. However, majority of those variants have not been characterized and their functional consequence remains largely unknown. Rs77542162 is a common missense variant in ABCA6 and is strongly associated with hypercholesterolemia in different populations. ABCA6 is a cholesterol responsive gene and has been suggested to play a role in lipid metabolism. However, whether and how rs77542162 and ABCA6 regulate lipoprotein metabolism remain unknown. In current study, we systemically characterized the function of rs77542162 and ABCA6 in cultured cells and in vivo of rodents. We found that Abca6 is specifically expressed on the basolateral surface of hepatocytes in mouse liver. The rs77542162 variant disrupts ABCA6 protein stability and results in loss of functional protein. However, we found no evidence that Abca6 plays a role in lipoprotein metabolism in either normal mice or hypercholesterolemia mice or hamsters. Thus, our results suggest that Abca6 does not regulate lipoprotein metabolism in rodents and highlight the challenge and importance of functional characterization of disease-associated variants in animal models.
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Affiliation(s)
- Baoshen He
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
| | - Shijia Kang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
| | - Zhen Chen
- Hubei Key Laboratory of Developmentally Originated Disease, School of Basic Medical Sciences Wuhan University, Wuhan 430072, People's Republic of China.
| | - Xiao Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
| | - Jinkai Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
| | - Xuedan Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
| | - Xiaomin Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
| | - Ling Zheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
| | - Mengcheng Luo
- Hubei Key Laboratory of Developmentally Originated Disease, School of Basic Medical Sciences Wuhan University, Wuhan 430072, People's Republic of China.
| | - Yan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
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19
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Tam J, Thankam F, Agrawal DK, Radwan MM. Critical Role of LOX-1-PCSK9 Axis in the Pathogenesis of Atheroma Formation and Its Instability. Heart Lung Circ 2021; 30:1456-1466. [PMID: 34092505 DOI: 10.1016/j.hlc.2021.05.085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/15/2021] [Accepted: 05/03/2021] [Indexed: 12/12/2022]
Abstract
Cardiovascular disease (CVD) is a major contributor to annual deaths globally. Atherosclerosis is a prominent risk factor for CVD. Although significant developments have been recently made in the prevention and treatment, the molecular pathology of atherosclerosis remains unknown. Interestingly, the recent discovery of proprotein convertase subtilisin/kexin type 9 (PCSK9) introduced a new avenue to explore the molecular pathogenesis and novel management strategies for atherosclerosis. Initial research focussed on the PCSK9-mediated degradation of low density lipoprotein receptor (LDLR) and subsequent activation of pro-inflammatory pathways by oxidised low density lipoprotein (ox-LDL). Recently, PCSK9 and lectin-like oxidised low-density lipoprotein receptor-1 (LOX-1) were shown to positively amplify each other pro-inflammatory activity and gene expression in endothelial cells, macrophages and vascular smooth muscle cells. In this literature review, we provide insight into the reciprocal relationship between PCSK9 and LOX-1 in the pathogenesis of atheroma formation and plaque instability in atherosclerosis. Further understanding of the LOX-1-PCSK9 axis possesses tremendous translational potential to design novel management approaches for atherosclerosis.
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Affiliation(s)
- Jonathan Tam
- Department of Translational Research, Western University of Health Sciences, Pomona, CA, USA
| | - Finosh Thankam
- Department of Translational Research, Western University of Health Sciences, Pomona, CA, USA
| | - Devendra K Agrawal
- Department of Translational Research, Western University of Health Sciences, Pomona, CA, USA
| | - Mohamed M Radwan
- Department of Translational Research, Western University of Health Sciences, Pomona, CA, USA.
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20
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Development of a novel, fully human, anti-PCSK9 antibody with potent hypolipidemic activity by utilizing phage display-based strategy. EBioMedicine 2021; 65:103250. [PMID: 33647772 PMCID: PMC7921758 DOI: 10.1016/j.ebiom.2021.103250] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/27/2021] [Accepted: 02/03/2021] [Indexed: 12/19/2022] Open
Abstract
Background Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates serum LDL cholesterol (LDL-C) levels by facilitating the degradation of the LDL receptor (LDLR) and is an attractive therapeutic target for hypercholesterolemia intervention. Herein, we generated a novel fully human antibody with favourable druggability by utilizing phage display-based strategy. Methods A potent single-chain variable fragment (scFv) named AP2M21 was obtained by screening a fully human scFv phage display library with hPCSK9, and performing two in vitro affinity maturation processes including CDR-targeted tailored mutagenesis and cross-cloning. Thereafter, it was transformed to a full-length Fc-silenced anti-PCSK9 antibody FAP2M21 by fusing to a modified human IgG1 Fc fragment with L234A/L235A/N297G mutations and C-terminal lysine deletion, thus eliminating its immune effector functions and mitigating mAb heterogeneity. Findings Our data showed that the generated full-length anti-PCSK9 antibody FAP2M21 binds to hPCSK9 with a KD as low as 1.42 nM, and a dramatically slow dissociation rate (koff, 4.68 × 10−6 s−1), which could be attributed to its lower binding energy (-47.51 kcal/mol) than its parent counterpart FAP2 (-30.39 kcal/mol). We verified that FAP2M21 potently inhibited PCSK9-induced reduction of LDL-C uptake in HepG2 cells, with an EC50 of 43.56 nM. Further, in hPCSK9 overexpressed C57BL/6 mice, a single tail i.v. injection of FAP2M21 at 1, 3 and 10 mg/kg, dose-dependently up-regulated hepatic LDLR levels, and concomitantly reduced serum LDL-C by 3.3% (P = 0.658, unpaired Student's t-test), 30.2% (P = 0.002, Mann-Whitney U-test) and 37.2% (P = 0.002, Mann-Whitney U-test), respectively. Interpretation FAP2M21 with potent inhibitory effect on PCSK9 may serve as a promising therapeutic agent for treating hypercholesterolemia and associated cardiovascular diseases.
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21
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The Cholesterol-Lowering Effect of Capsella Bursa-Pastoris Is Mediated via SREBP2 and HNF-1α-Regulated PCSK9 Inhibition in Obese Mice and HepG2 Cells. Foods 2021; 10:foods10020408. [PMID: 33673187 PMCID: PMC7918551 DOI: 10.3390/foods10020408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/06/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022] Open
Abstract
The objective of the present study was to investigate the mechanism by which capsella bursa-pastoris ethanol extract (CBE), containing 17.5 milligrams of icaritin per kilogram of the extract, and icaritin, mediate hypocholesterolemic activity via the low-density lipoprotein receptor (LDLR) and pro-protein convertase subtilisin/kexin type 9 (PCSK9) in obese mice and HepG2 cells. CBE significantly attenuated serum total and LDL cholesterol levels in obese mice, which was associated with significantly decreased PCSK9 gene expression. HepG2 cells were cultured using delipidated serum (DLPS), and CBE significantly reduced PCSK9 and maintained the LDLR level. CBE co-treatment with rosuvastatin attenuated statin-mediated PCSK9 expression, and further increased LDLR. The icaritin contained in CBE decreased intracellular PCSK9 and LDLR levels by suppressing transcription factors SREBP2 and HNF-1α. Icaritin also significantly suppressed the extracellular PCSK9 level, which likely contributed to post-translational stabilization of LDLR in the HepG2 cells. PCSK9 inhibition by CBE is actively attributed to icaritin, and the use of CBE and icaritin could be an alternative therapeutic approach in the treatment of hypercholesterolemia.
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Zou Y, Li S, Xu B, Guo H, Zhang S, Cai Y. Inhibition of Proprotein Convertase Subtilisin/Kexin Type 9 Ameliorates Liver Fibrosis via Mitigation of Intestinal Endotoxemia. Inflammation 2020; 43:251-263. [PMID: 31776890 DOI: 10.1007/s10753-019-01114-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lipopolysaccharide (LPS) is demonstrated to cause "two-hit" injury to liver. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an important role in LPS clearance. Hepatocyte nuclear factor-1 alpha (HNF-1α) and sterol regulatory element-binding protein 2 (SREBP2) were reported to be responsible for PCSK9 gene transcription and regulation. We aim to clarify the expression status of PCSK9 during the process of liver fibrosis and to verify the effect on liver fibrosis via PCSK9 inhibition. In this study, we found that PCSK9 increased significantly in human and BDL mouse injured liver tissues, so did HNF-1α and SREBP2. No significant difference of plasma PCSK9 was observed. Inhibited PCSK9 using CRISPR-PCSK9 adeno-associated virus in BDL mice ameliorated liver inflammation and fibrosis, with LPS decrease in serum, without any change in intestinal wall integrity. PCSK9 expression of L02 hepatocytes can be induced by LPS; however, they lose the ability at high content of LPS. L02 cells increased LPS uptake after PCSK9 knockout. Taken together, these results suggest that, with PCSK9 increasing during liver fibrosis advancement, its inhibition can ameliorate liver injury by enhancing LPS uptake in hepatocytes; however, the enhancement is limited for destruction to hepatocytes by high LPS.
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Affiliation(s)
- Yanting Zou
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Xuhui District, Shanghai, People's Republic of China
| | - Shuyu Li
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Xuhui District, Shanghai, People's Republic of China
| | - Beili Xu
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Xuhui District, Shanghai, People's Republic of China
| | - Hongying Guo
- Department of Severe Hepatitis, Shanghai Public Health Clinical Center, Fudan University, 2901 Caolang Road, Jinshan District, Shanghai, People's Republic of China
| | - Shuncai Zhang
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Xuhui District, Shanghai, People's Republic of China
| | - Yu Cai
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Xuhui District, Shanghai, People's Republic of China.
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Roger C, Buch C, Muller T, Leemput J, Demizieux L, Passilly-Degrace P, Cinar R, Iyer MR, Kunos G, Vergès B, Degrace P, Jourdan T. Simultaneous Inhibition of Peripheral CB1R and iNOS Mitigates Obesity-Related Dyslipidemia Through Distinct Mechanisms. Diabetes 2020; 69:2120-2132. [PMID: 32680936 PMCID: PMC7506827 DOI: 10.2337/db20-0078] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 07/05/2020] [Indexed: 12/17/2022]
Abstract
Diabetic dyslipidemia, characterized by increased plasma triglycerides and decreased HDL cholesterol levels, is a major factor contributing to nonalcoholic steatohepatitis and cardiovascular risk in type 2 diabetes. Activation of the cannabinoid-1 receptor (CB1R) and activation of inducible nitric oxide synthase (iNOS) are associated with nonalcoholic steatohepatitis progression. Here, we tested whether dual-targeting inhibition of hepatic CB1R and iNOS improves diabetic dyslipidemia in mice with diet-induced obesity (DIO mice). DIO mice were treated for 14 days with (S)-MRI-1867, a peripherally restricted hybrid inhibitor of CB1R and iNOS. (R)-MRI-1867, the CB1R-inactive stereoisomer that retains iNOS inhibitory activity, and JD-5037, a peripherally restricted CB1R antagonist, were used to assess the relative contribution of the two targets to the effects of (S)-MRI-1867. (S)-MRI-1867 reduced hepatic steatosis and the rate of hepatic VLDL secretion, upregulated hepatic LDLR expression, and reduced the circulating levels of proprotein convertase subtilisin/kexin type 9 (PCSK9). The decrease in VLDL secretion could be attributed to CB1R blockade, while the reduction of PCSK9 levels and the related increase in LDLR resulted from iNOS inhibition via an mTOR complex 1-dependent mechanism. In conclusion, this approach based on the concomitant inhibition of CB1R and iNOS represents a promising therapeutic strategy for the treatment of dyslipidemia.
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Affiliation(s)
- Célia Roger
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Chloé Buch
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Tania Muller
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Julia Leemput
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Laurent Demizieux
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Patricia Passilly-Degrace
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Malliga R Iyer
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Bruno Vergès
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Pascal Degrace
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Tony Jourdan
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
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Martinelli L, Adamopoulos A, Johansson P, Wan PT, Gunnarsson J, Guo H, Boyd H, Zelcer N, Sixma TK. Structural analysis of the LDL receptor-interacting FERM domain in the E3 ubiquitin ligase IDOL reveals an obscured substrate-binding site. J Biol Chem 2020; 295:13570-13583. [PMID: 32727844 PMCID: PMC7521653 DOI: 10.1074/jbc.ra120.014349] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/21/2020] [Indexed: 12/31/2022] Open
Abstract
Hepatic abundance of the low-density lipoprotein receptor (LDLR) is a critical determinant of circulating plasma LDL cholesterol levels and hence development of coronary artery disease. The sterol-responsive E3 ubiquitin ligase inducible degrader of the LDLR (IDOL) specifically promotes ubiquitination and subsequent lysosomal degradation of the LDLR and thus controls cellular LDL uptake. IDOL contains an extended N-terminal FERM (4.1 protein, ezrin, radixin, and moesin) domain, responsible for substrate recognition and plasma membrane association, and a second C-terminal RING domain, responsible for the E3 ligase activity and homodimerization. As IDOL is a putative lipid-lowering drug target, we investigated the molecular details of its substrate recognition. We produced and isolated full-length IDOL protein, which displayed high autoubiquitination activity. However, in vitro ubiquitination of its substrate, the intracellular tail of the LDLR, was low. To investigate the structural basis for this, we determined crystal structures of the extended FERM domain of IDOL and multiple conformations of its F3ab subdomain. These reveal the archetypal F1-F2-F3 trilobed FERM domain structure but show that the F3c subdomain orientation obscures the target-binding site. To substantiate this finding, we analyzed the full-length FERM domain and a series of truncated FERM constructs by small-angle X-ray scattering (SAXS). The scattering data support a compact and globular core FERM domain with a more flexible and extended C-terminal region. This flexibility may explain the low activity in vitro and suggests that IDOL may require activation for recognition of the LDLR.
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Affiliation(s)
- Luca Martinelli
- Division of Biochemistry, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Amsterdam, the Netherlands
| | | | - Patrik Johansson
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Paul T Wan
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Jenny Gunnarsson
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Hongwei Guo
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Helen Boyd
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Noam Zelcer
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Amsterdam, the Netherlands.
| | - Titia K Sixma
- Division of Biochemistry, Netherlands Cancer Institute, Amsterdam, The Netherlands; Oncode Institute, Utrecht, The Netherlands.
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Deng SJ, Shen Y, Gu HM, Guo S, Wu SR, Zhang DW. The role of the C-terminal domain of PCSK9 and SEC24 isoforms in PCSK9 secretion. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158660. [DOI: 10.1016/j.bbalip.2020.158660] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/16/2022]
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Guo S, Xia XD, Gu HM, Zhang DW. Proprotein Convertase Subtilisin/Kexin-Type 9 and Lipid Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:137-156. [DOI: 10.1007/978-981-15-6082-8_9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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27
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Mechanisms and regulation of cholesterol homeostasis. Nat Rev Mol Cell Biol 2019; 21:225-245. [DOI: 10.1038/s41580-019-0190-7] [Citation(s) in RCA: 450] [Impact Index Per Article: 90.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2019] [Indexed: 12/14/2022]
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Spolitu S, Okamoto H, Dai W, Zadroga JA, Wittchen ES, Gromada J, Ozcan L. Hepatic Glucagon Signaling Regulates PCSK9 and Low-Density Lipoprotein Cholesterol. Circ Res 2019; 124:38-51. [PMID: 30582457 DOI: 10.1161/circresaha.118.313648] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
RATIONALE Glucagon is a key hormone that regulates the adaptive metabolic responses to fasting. In addition to maintaining glucose homeostasis, glucagon participates in the regulation of cholesterol metabolism; however, the molecular pathways underlying this effect are incompletely understood. OBJECTIVE We sought to determine the role of hepatic Gcgr (glucagon receptor) signaling in plasma cholesterol regulation and identify its underlying molecular mechanisms. METHODS AND RESULTS We show that Gcgr signaling plays an essential role in LDL-C (low-density lipoprotein cholesterol) homeostasis through regulating the PCSK9 (proprotein convertase subtilisin/kexin type 9) levels. Silencing of hepatic Gcgr or inhibition of glucagon action increased hepatic and plasma PCSK9 and resulted in lower LDLR (LDL receptor) protein and increased plasma LDL-C. Conversely, treatment of wild-type (WT) mice with glucagon lowered LDL-C levels, whereas this response was abrogated in Pcsk9-/- and Ldlr-/- mice. Our gain- and loss-of-function studies identified Epac2 (exchange protein activated by cAMP-2) and Rap1 (Ras-related protein-1) as the downstream mediators of glucagon's action on PCSK9 homeostasis. Moreover, mechanistic studies revealed that glucagon affected the half-life of PCSK9 protein without changing the level of its mRNA, indicating that Gcgr signaling regulates PCSK9 degradation. CONCLUSIONS These findings provide novel insights into the molecular interplay between hepatic glucagon signaling and lipid metabolism and describe a new posttranscriptional mechanism of PCSK9 regulation.
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Affiliation(s)
- Stefano Spolitu
- From the Department of Medicine, Columbia University, New York (S.S., W.D., J.A.Z., L.O.)
| | - Haruka Okamoto
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY (H.O., J.G.)
| | - Wen Dai
- From the Department of Medicine, Columbia University, New York (S.S., W.D., J.A.Z., L.O.)
| | - John A Zadroga
- From the Department of Medicine, Columbia University, New York (S.S., W.D., J.A.Z., L.O.)
| | - Erika S Wittchen
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill (E.S.W.)
| | - Jesper Gromada
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY (H.O., J.G.)
| | - Lale Ozcan
- From the Department of Medicine, Columbia University, New York (S.S., W.D., J.A.Z., L.O.)
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Miyazaki T, Miyazaki A. Impact of Dysfunctional Protein Catabolism on Macrophage Cholesterol Handling. Curr Med Chem 2019; 26:1631-1643. [PMID: 29589525 DOI: 10.2174/0929867325666180326165234] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/24/2017] [Accepted: 12/26/2017] [Indexed: 12/18/2022]
Abstract
Protein catabolism in macrophages, which is accomplished mainly through autophagy- lysosomal degradation, ubiquitin-proteasome system, and calpains, is disturbed in atheroprone vessels. Moreover, growing evidence suggests that defects in protein catabolism interfere with cholesterol handling in macrophages. Indeed, decreases in autophagy facilitate the deposition of cholesterol in atheroprone macrophages and the subsequent development of vulnerable atherosclerotic plaques due to impaired catabolism of lipid droplets and limited efferocytic clearance of dead cells. The proteasome is responsible for the degradation of ATP-binding cassette transporters, which leads to impaired cholesterol efflux from macrophages. Overactivation of conventional calpains contributes to excessive processing of functional proteins, thereby accelerating receptor-mediated uptake of oxidized low-density lipoproteins (LDLs) and slowing cholesterol efflux. Furthermore, calpain-6, an unconventional nonproteolytic calpain in macrophages, potentiates pinocytotic uptake of native LDL and attenuates the efferocytic clearance of dead cells. Herein, we focus on recent progress in understanding how defective protein catabolism is associated with macrophage cholesterol handling and subsequent atherogenesis.
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Affiliation(s)
- Takuro Miyazaki
- Department of Biochemistry, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Akira Miyazaki
- Department of Biochemistry, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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Ginkgolide B Mediated Alleviation of Inflammatory Cascades and Altered Lipid Metabolism in HUVECs via Targeting PCSK-9 Expression and Functionality. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7284767. [PMID: 31281844 PMCID: PMC6590504 DOI: 10.1155/2019/7284767] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 05/13/2019] [Accepted: 05/26/2019] [Indexed: 01/06/2023]
Abstract
The potential of oxidized-LDL (Ox-LDL) to elicit inflammatory responses in macrophages leading to the atherosclerosis (AS) progression is well known. Since proprotein convertase subtilisin/Kexin-9 (PCSK-9), the posttranslational regulator of LDL-receptor, is associated with elevated LDL in the circulation, the present report was aimed to uncover the ameliorative effects of Ginkgolide B, a terpenic lactone from Ginkgo biloba, against Ox-LDL-induced alterations in cholesterol metabolism in HUVECs. Consequently, our results demonstrated that incubation with Ox-LDL significantly upregulated the PCSK-9 expression in HUVECs, which was significantly downregulated, both at mRNA and protein level, after Ginkgolide B treatment via subsequent suppression of sterol element binding protein (SREBP-2) expression. Moreover, Ginkgolide B-mediated inhibition of PCSK-9 activity was also validated by in silico methods which revealed that it interferes the PSCK-9 interaction with LDL-receptor (LDL-R). Interestingly, Ox-LDL-induced LDL-R expression was further enhanced by Ginkgolide B treatment in HUVECs. Moreover, Ginkgolide B treatment lead to downregulation of lectin-like Ox-LDL receptor (LOX-1) and NADPH oxidase (NOX-4) expression which was upregulated in Ox-LDL-treated HUVECs, along with the attenuation of mitochondrial ROS generation. Furthermore, Ginkgolide B significantly inhibited the augmented expression of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) in Ox-LDL-activated HUVECs. Ginkgolide B also significantly ameliorated the inflammatory response in Ox-LDL-activated HUVECs by suppressing the expression of IL-1α, IL-1β, IL-6, CXCL-1, CXCL-2, and monocyte chemotactic protein (MCP-1), at mRNA and protein level. Our in vitro and in silico study established that Ginkgolide B alleviated the Ox-LDL-induced inflammatory cascades and altered lipid metabolism in HUVECs by suppressing the PCSK-9 and, thus, could be established as a treasured alternative therapeutic candidate in the atherosclerosis management.
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Wijers M, Zanoni P, Liv N, Vos DY, Jäckstein MY, Smit M, Wilbrink S, Wolters JC, van der Veen YT, Huijkman N, Dekker D, Kloosterhuis N, van Dijk TH, Billadeau DD, Kuipers F, Klumperman J, von Eckardstein A, Kuivenhoven JA, van de Sluis B. The hepatic WASH complex is required for efficient plasma LDL and HDL cholesterol clearance. JCI Insight 2019; 4:126462. [PMID: 31167970 DOI: 10.1172/jci.insight.126462] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 04/17/2019] [Indexed: 12/21/2022] Open
Abstract
The evolutionary conserved Wiskott-Aldrich syndrome protein and SCAR homolog (WASH) complex is one of the crucial multiprotein complexes that facilitates endosomal recycling of transmembrane proteins. Defects in WASH components have been associated with inherited developmental and neurological disorders in humans. Here, we show that hepatic ablation of the WASH component Washc1 in chow-fed mice increases plasma concentrations of cholesterol in both LDLs and HDLs, without affecting hepatic cholesterol content, hepatic cholesterol synthesis, biliary cholesterol excretion, or hepatic bile acid metabolism. Elevated plasma LDL cholesterol was related to reduced hepatocytic surface levels of the LDL receptor (LDLR) and the LDLR-related protein LRP1. Hepatic WASH ablation also reduced the surface levels of scavenger receptor class B type I and, concomitantly, selective uptake of HDL cholesterol into the liver. Furthermore, we found that WASHC1 deficiency increases LDLR proteolysis by the inducible degrader of LDLR, but does not affect proprotein convertase subtilisin/kexin type 9-mediated LDLR degradation. Remarkably, however, loss of hepatic WASHC1 may sensitize LDLR for proprotein convertase subtilisin/kexin type 9-induced degradation. Altogether, these findings identify the WASH complex as a regulator of LDL as well as HDL metabolism and provide in vivo evidence for endosomal trafficking of scavenger receptor class B type I in hepatocytes.
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Affiliation(s)
- Melinde Wijers
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Paolo Zanoni
- Institute for Clinical Chemistry, University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Nalan Liv
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Dyonne Y Vos
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Michelle Y Jäckstein
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Marieke Smit
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Sanne Wilbrink
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Justina C Wolters
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Ydwine T van der Veen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Nicolette Huijkman
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Daphne Dekker
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Niels Kloosterhuis
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Theo H van Dijk
- Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Daniel D Billadeau
- Department of Immunology and Biochemistry, Division of Oncology Research, Mayo Clinic, Rochester, New York, USA
| | - Folkert Kuipers
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands.,Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Arnold von Eckardstein
- Institute for Clinical Chemistry, University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Jan Albert Kuivenhoven
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Bart van de Sluis
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
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Rawther T, Tabet F. Biology, pathophysiology and current therapies that affect lipoprotein (a) levels. J Mol Cell Cardiol 2019; 131:1-11. [DOI: 10.1016/j.yjmcc.2019.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 03/22/2019] [Accepted: 04/09/2019] [Indexed: 12/11/2022]
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Abstract
PURPOSE OF REVIEW The purpose of this review is to highlight the recent findings of one of the most promising therapeutic targets in LDL cholesterol (LDL-C) management, proprotein convertase subtilisin/kexin type 9 (PCSK9). RECENT FINDINGS Endoplasmic reticulum cargo receptor, surfeit locus protein 4 interacts with PCSK9 and regulates its exit from endoplasmic reticulum and its secretion. Once secreted, PCSK9 binds to heparin sulfate proteoglycans on the hepatocyte surface and this binding is required for PCSK9-LDL receptor (LDLR) complex formation and LDLR degradation. Posttranscriptionally, recent work has shown that PCSK9 gets degraded in lysosomes by activation of the glucagon receptor signaling, providing more data on the hormonal regulation of PCSK9. Finally, human studies with PCSK9 inhibitors offered more evidence on their benefits and safe use. SUMMARY Recent work on the regulation of PCSK9 has enhanced our understanding of its biology, which may provide important information for future PCSK9-based therapies.
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Affiliation(s)
- Stefano Spolitu
- Department of Medicine, Columbia University, New York, New York, USA
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34
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Xiao J, Deng YM, Liu XR, Cao JP, Zhou M, Tang YL, Xiong WH, Jiang ZS, Tang ZH, Liu LS. PCSK9: A new participant in lipophagy in regulating atherosclerosis? Clin Chim Acta 2019; 495:358-364. [PMID: 31075236 DOI: 10.1016/j.cca.2019.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/03/2019] [Accepted: 05/06/2019] [Indexed: 12/12/2022]
Abstract
Proprotein convertase subtilisin kexin 9 (PCSK9) regulates lipid metabolism by degrading low-density lipoprotein receptor on the surface of hepatocytes. PCSK9-mediated lipid degradation is associated with lipophagy. Lipophagy is a process by which autophagosomes selectively sequester lipid-droplet-stored lipids and are delivered to lysosomes for degradation. Lipophagy was first discovered in hepatocytes, and its occurrence provides important fundamental insights into how lipid metabolism regulates cellular physiology and pathophysiology. Furthermore, PCSK9 may regulate lipid levels by affecting lipophagy. This review will discuss recent advances by which PCSK9 mediates lipid degradation via the lipophagy pathway and present lipophagy as a potential therapeutic target for atherosclerosis.
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Affiliation(s)
- Jun Xiao
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China
| | - Yi-Min Deng
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China
| | - Xiang-Rui Liu
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China
| | - Jian-Ping Cao
- Hunan Environmental Biology Vocational and Technical College, Hengyang, Hunan 421001, PR China
| | - Min Zhou
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China
| | - Ya-Ling Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China
| | - Wen-Hao Xiong
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China
| | - Zhi-Sheng Jiang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China
| | - Zhi-Han Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China.
| | - Lu-Shan Liu
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, University of South China, Hengyang, Hunan 421001, PR China.
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Lebeau PF, Byun JH, Platko K, MacDonald ME, Poon SV, Faiyaz M, Seidah NG, Austin RC. Diet-induced hepatic steatosis abrogates cell-surface LDLR by inducing de novo PCSK9 expression in mice. J Biol Chem 2019; 294:9037-9047. [PMID: 31004037 DOI: 10.1074/jbc.ra119.008094] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/09/2019] [Indexed: 12/11/2022] Open
Abstract
The worldwide prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing rapidly. Although this condition is generally benign, accumulating evidence now suggests that patients with NAFLD are also at increased risk of cardiovascular disease (CVD); the leading cause of death in developed nations. Despite the well-established role of the liver as a central regulator of circulating low-density lipoprotein (LDL) cholesterol levels, a known driver of CVD, the mechanism(s) by which hepatic steatosis contributes to CVD remains elusive. Interestingly, a recent study has shown that circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) levels correlate positively with liver steatosis grade. Given that PCSK9 degrades the LDL receptor (LDLR) and prevents the removal of LDL from the blood into the liver, in the present study we examined the effect of hepatic steatosis on LDLR expression and circulating LDL cholesterol levels. We now report that in a manner consistent with findings in patients, diet-induced steatosis increases circulating PCSK9 levels as a result of de novo expression in mice. We also report the finding that steatosis abrogates hepatic LDLR expression and increases circulating LDL levels in a PCSK9-dependent manner. These findings provide important mechanistic insights as to how hepatic steatosis modulates lipid regulatory genes, including PCSK9 and the LDLR, and also highlights a novel mechanism by which liver disease may contribute to CVD.
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Affiliation(s)
- Paul F Lebeau
- From the Department of Medicine, McMaster University, The Research Institute of St. Joe's Hamilton, Hamilton, Ontario L8N 4A6 and
| | - Jae Hyun Byun
- From the Department of Medicine, McMaster University, The Research Institute of St. Joe's Hamilton, Hamilton, Ontario L8N 4A6 and
| | - Khrystyna Platko
- From the Department of Medicine, McMaster University, The Research Institute of St. Joe's Hamilton, Hamilton, Ontario L8N 4A6 and
| | - Melissa E MacDonald
- From the Department of Medicine, McMaster University, The Research Institute of St. Joe's Hamilton, Hamilton, Ontario L8N 4A6 and
| | - Samantha V Poon
- From the Department of Medicine, McMaster University, The Research Institute of St. Joe's Hamilton, Hamilton, Ontario L8N 4A6 and
| | - Mahi Faiyaz
- From the Department of Medicine, McMaster University, The Research Institute of St. Joe's Hamilton, Hamilton, Ontario L8N 4A6 and
| | - Nabil G Seidah
- the Laboratory of Biochemical Neuroendocrinology, Montreal Clinical Research Institute, University of Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Richard C Austin
- From the Department of Medicine, McMaster University, The Research Institute of St. Joe's Hamilton, Hamilton, Ontario L8N 4A6 and
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Fu W, Gao XP, Zhang S, Dai YP, Zou WJ, Yue LM. 17β-Estradiol Inhibits PCSK9-Mediated LDLR Degradation Through GPER/PLC Activation in HepG2 Cells. Front Endocrinol (Lausanne) 2019; 10:930. [PMID: 32082252 PMCID: PMC7002320 DOI: 10.3389/fendo.2019.00930] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 12/20/2019] [Indexed: 12/22/2022] Open
Abstract
Plasma levels of PCSK9 are significantly higher in postmenopausal women. Pharmacologically increased estrogen levels have been shown to lower PCSK9 and LDL-C levels in animals and humans. The action of estrogen suggests that it has the ability to prevent PCSK9-mediated LDLR degradation in liver cells. However, little is known about how estrogen alters PCSK9-mediated LDLR degradation. Here, we report that 17β-estradiol (βE2) reduces PCSK9-mediated LDLR degradation by a mechanism that involves activation of the G protein-coupled estrogen receptor (GPER). In cultured HepG2 cells, βE2 prevented the internalization of PCSK9, which subsequently lead to PCSK9-mediated LDLR degradation. The altered LDLR levels also resulted in an increase in LDL uptake that was not observed in the absence of PCSK9. In addition, we showed that clathrin was rapidly increased in the presence of PCSK9, and this increase was blocked by βE2 incubation, suggesting rapid recruitment of clathrin in HepG2 cells. PLCγ activation and intracellular Ca2+ release were both increased due to the rapid effect of estrogen. By using a GPER antagonist G15, we demonstrated that the GPER mediates the action of estrogen. Together, the data from this in vitro study demonstrate that estrogen can regulate LDLR levels mainly through GPER activation, which prevents PCSK9-dependent LDLR degradation in HepG2 cells.
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Affiliation(s)
- Wei Fu
- Department of Physiology, West China School of Basic Medical and Forensic Medicine, Sichuan University, Chengdu, China
| | - Xiao-Ping Gao
- College of Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Sheng Zhang
- Department of Physiology, West China School of Basic Medical and Forensic Medicine, Sichuan University, Chengdu, China
| | - Yan-Ping Dai
- College of Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Wen-Jun Zou
- College of Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Li-Min Yue
- Department of Physiology, West China School of Basic Medical and Forensic Medicine, Sichuan University, Chengdu, China
- *Correspondence: Li-Min Yue
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Further evidence of novel APOB mutations as a cause of familial hypercholesterolaemia. Atherosclerosis 2018; 277:448-456. [DOI: 10.1016/j.atherosclerosis.2018.06.819] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/06/2018] [Accepted: 06/14/2018] [Indexed: 01/02/2023]
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Fedoseienko A, Wijers M, Wolters JC, Dekker D, Smit M, Huijkman N, Kloosterhuis N, Klug H, Schepers A, Willems van Dijk K, Levels JHM, Billadeau DD, Hofker MH, van Deursen J, Westerterp M, Burstein E, Kuivenhoven JA, van de Sluis B. The COMMD Family Regulates Plasma LDL Levels and Attenuates Atherosclerosis Through Stabilizing the CCC Complex in Endosomal LDLR Trafficking. Circ Res 2018; 122:1648-1660. [PMID: 29545368 DOI: 10.1161/circresaha.117.312004] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 03/03/2018] [Accepted: 03/13/2018] [Indexed: 12/31/2022]
Abstract
RATIONALE COMMD (copper metabolism MURR1 domain)-containing proteins are a part of the CCC (COMMD-CCDC22 [coiled-coil domain containing 22]-CCDC93 [coiled-coil domain containing 93]) complex facilitating endosomal trafficking of cell surface receptors. Hepatic COMMD1 inactivation decreases CCDC22 and CCDC93 protein levels, impairs the recycling of the LDLR (low-density lipoprotein receptor), and increases plasma low-density lipoprotein cholesterol levels in mice. However, whether any of the other COMMD members function similarly as COMMD1 and whether perturbation in the CCC complex promotes atherogenesis remain unclear. OBJECTIVE The main aim of this study is to unravel the contribution of evolutionarily conserved COMMD proteins to plasma lipoprotein levels and atherogenesis. METHODS AND RESULTS Using liver-specific Commd1, Commd6, or Commd9 knockout mice, we investigated the relation between the COMMD proteins in the regulation of plasma cholesterol levels. Combining biochemical and quantitative targeted proteomic approaches, we found that hepatic COMMD1, COMMD6, or COMMD9 deficiency resulted in massive reduction in the protein levels of all 10 COMMDs. This decrease in COMMD protein levels coincided with destabilizing of the core (CCDC22, CCDC93, and chromosome 16 open reading frame 62 [C16orf62]) of the CCC complex, reduced cell surface levels of LDLR and LRP1 (LDLR-related protein 1), followed by increased plasma low-density lipoprotein cholesterol levels. To assess the direct contribution of the CCC core in the regulation of plasma cholesterol levels, Ccdc22 was deleted in mouse livers via CRISPR/Cas9-mediated somatic gene editing. CCDC22 deficiency also destabilized the complete CCC complex and resulted in elevated plasma low-density lipoprotein cholesterol levels. Finally, we found that hepatic disruption of the CCC complex exacerbates dyslipidemia and atherosclerosis in ApoE3*Leiden mice. CONCLUSIONS Collectively, these findings demonstrate a strong interrelationship between COMMD proteins and the core of the CCC complex in endosomal LDLR trafficking. Hepatic disruption of either of these CCC components causes hypercholesterolemia and exacerbates atherosclerosis. Our results indicate that not only COMMD1 but all other COMMDs and CCC components may be potential targets for modulating plasma lipid levels in humans.
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Affiliation(s)
- Alina Fedoseienko
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Melinde Wijers
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Justina C Wolters
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Daphne Dekker
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Marieke Smit
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Nicolette Huijkman
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Niels Kloosterhuis
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Helene Klug
- University Medical Center Groningen, University of Groningen, The Netherlands; PolyQuant GmbH, Bad Abbach, Germany (H.K.)
| | - Aloys Schepers
- Monoclonal Antibody Core Facility and Research Group, Institute for Diabetes and Obesity, Helmholtz Zentrum, München, Germany (A.S.)
| | - Ko Willems van Dijk
- Department of Human Genetics (K.W.v.D.) and Department of Medicine (K.W.v.D.)
| | - Johannes H M Levels
- Division of Endocrinology, Leiden University Medical Center, The Netherlands; Department of Vascular and Experimental Vascular Medicine, Academic Medical Center, University of Amsterdam, The Netherlands (J.H.M.L.)
| | - Daniel D Billadeau
- Division of Oncology Research, Department of Immunology and Biochemistry (D.D.B.)
| | - Marten H Hofker
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Jan van Deursen
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine (J.v.D.).,Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine (J.v.D.)
| | - Marit Westerterp
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Ezra Burstein
- Mayo Clinic, Rochester, MN; and University of Texas Southwestern Medical Center, Dallas (E.B.)
| | - Jan Albert Kuivenhoven
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S)
| | - Bart van de Sluis
- From the Molecular Genetics Section, Department of Pediatrics (A.F., M. Wijers, J.C.W., D.D., M.S., N.H., N.K., M.H.H., M. Westerterp, J.A.K., B.v.d.S) .,iPSC/CRISPR Center Groningen (B.v.d.S.)
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Wiciński M, Żak J, Malinowski B, Popek G, Grześk G. PCSK9 signaling pathways and their potential importance in clinical practice. EPMA J 2017; 8:391-402. [PMID: 29209441 PMCID: PMC5700013 DOI: 10.1007/s13167-017-0106-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/30/2017] [Indexed: 12/15/2022]
Abstract
In the following review, authors described the structure and biochemical pathways of PCSK9, its involvement in LDL metabolism, as well as significances of proprotein convertase subtilisin/kexin type 9 targeted treatment. PCSK9 is a proprotein convertase, which plays a crucial role in LDL receptor metabolism. Transcription and translation of PCSK9 is controlled by different nuclear factors, such as, SREBP and HNF1α. This review focuses on interactions between PCSK9 and LDL receptor, VLDLR, ApoER2, CD36, CD81, and others. The role of PCSK9 in the inflammatory process is presented and its influence on cytokine profile (IL-1, IL-6, IL-10, TNF) in atherosclerotic plaque. Cholesterol metabolism converges also with diabetes by mTORC1 pathways. PCSK9 can be altered by oncologic pathways with utilization of kinases, such as Akt, JNK, and JAK/STAT. Finally, the article shows that blocking PCSK9 has proapoptotic capabilities. Administration of monoclonal antibodies against PCSK9 reduced mortality rate and cardiovascular events in randomized trials. On the other hand, immunogenicity of new drugs may play a crucial role in their efficiency. Bococizumab ended its career following SPIRE-1,2 outcome. PCSK9 inhibitors have enormous potential, which had been reflected by introducing them (as a new class of drugs reducing LDL concentration cholesterol) into New Lipid Guidelines from Rome 2016. Discoveries in drugs development are focused on blocking PCSK9 on different levels. For example, silencing messenger RNA (mRNA of PCSK9) is a new alternative against hypercholesterolemia. Peptides mimicking EGF-A domain of the LDL receptor are gaining significance and hopefully they will soon join others. The significance of PCSK9 has just been uncovered and further data is still required to understand their activity.
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Affiliation(s)
- Michał Wiciński
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Collegium, Medicum in Bydgoszcz, Nicolaus Copernicus University, 85-090 Bydgoszcz, Poland
| | - Jarosław Żak
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Collegium, Medicum in Bydgoszcz, Nicolaus Copernicus University, 85-090 Bydgoszcz, Poland
| | - Bartosz Malinowski
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Collegium, Medicum in Bydgoszcz, Nicolaus Copernicus University, 85-090 Bydgoszcz, Poland
| | - Gabriela Popek
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Collegium, Medicum in Bydgoszcz, Nicolaus Copernicus University, 85-090 Bydgoszcz, Poland
| | - Grzegorz Grześk
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Collegium, Medicum in Bydgoszcz, Nicolaus Copernicus University, 85-090 Bydgoszcz, Poland
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40
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Hypercholesterolemia: The role of PCSK9. Arch Biochem Biophys 2017; 625-626:39-53. [DOI: 10.1016/j.abb.2017.06.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/29/2017] [Accepted: 06/02/2017] [Indexed: 01/06/2023]
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41
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Li J, Liang X, Wang Y, Xu Z, Li G. Investigation of highly expressed PCSK9 in atherosclerotic plaques and ox-LDL-induced endothelial cell apoptosis. Mol Med Rep 2017; 16:1817-1825. [PMID: 28656218 PMCID: PMC5561783 DOI: 10.3892/mmr.2017.6803] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 02/02/2017] [Indexed: 11/13/2022] Open
Abstract
The present study aimed to explore the direct toxicity of proprotein convertase subtilisin/kexin type 9 (PCSK9) to atherosclerosis (AS) and its association with apoptotic endothelial cells. Apolipoprotein E−/− mice were randomly divided into two groups, control and experimental. The control group was administered a normal diet and the experimental group was administered a high-fat diet. After 20 weeks, the aorta was isolated and dissected. Hematoxylin and eosin staining, and immunohistochemical analysis were performed. Human umbilical vein endothelial cells were incubated with varied concentrations of oxidized low-density lipoprotein (ox-LDL) for different times. The apoptotic rate was detected by flow cytometry. Western blotting and reverse transcription-quantitative polymerase chain reaction analysis were conducted to detect the expression of PCSK9, B-cell lymphoma 2 (Bcl-2), bcl-2-like protein 4 (Bax) and caspase-3. Short hairpin (sh) RNA-PCSK9 was transfected into endothelial cells using lentiviral transfection. The expression levels of PCSK9, Bax, Bcl-2, caspase-3 and the mitogen-activated protein kinase (MAPK) pathway proteins were detected. The high-fat group was successfully established as an AS model and PCSK9 was highly expressed in the AS plaque. Treatment with ox-LDL induced apoptosis and increased mRNA and protein levels of PCSK9. PCSK9 mRNA and proteins levels were downregulated by shRNA-PCSK9. The deficiency of PCSK9 markedly inhibited the expression of pro-apoptotic proteins and promoted anti-apoptotic proteins. In addition, phosphorylation of p38 and c-Jun N-terminal kinases was altered by shRNA-PCSK9. Targeting of PCSK9 by shRNA-PCSK9 may repress endothelial cell apoptosis through MAPK signaling in AS, providing a novel direction for understanding the mechanism and treatment of AS.
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Affiliation(s)
- Jiao Li
- Tianjin Key Laboratory of Ionic‑Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin 300211, P.R. China
| | - Xue Liang
- Tianjin Key Laboratory of Ionic‑Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin 300211, P.R. China
| | - Yuanyuan Wang
- Tianjin Key Laboratory of Ionic‑Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin 300211, P.R. China
| | - Zhao Xu
- Tianjin Key Laboratory of Ionic‑Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin 300211, P.R. China
| | - Guangping Li
- Tianjin Key Laboratory of Ionic‑Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin 300211, P.R. China
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APP, APLP2 and LRP1 interact with PCSK9 but are not required for PCSK9-mediated degradation of the LDLR in vivo. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:883-889. [PMID: 28495363 DOI: 10.1016/j.bbalip.2017.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 05/05/2017] [Accepted: 05/05/2017] [Indexed: 12/21/2022]
Abstract
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that post-transcriptionally regulates the levels of hepatic low-density lipoprotein receptors (LDLRs). PCSK9 binds to the extracellular domain of the LDLR, and the PCSK9-LDLR complex is internalized through canonical clathrin-dependent endocytosis and then delivered to lysosomes for degradation. The mechanism by which PCSK9 blocks recycling of the LDLR has not been fully defined. Previous reports showed that amyloid precursor-like protein 2 (APLP2) interacts with PCSK9, but its role in PCSK9-mediated LDLR degradation remains controversial. Here we found that amyloid precursor protein (APP), APLP2 and LDL receptor-related protein 1 (LRP1) interact with PCSK9. To test whether any of these proteins are required for PCSK9-mediated LDLR degradation, we examined the effects of disrupting these proteins in mice. Infusion of PCSK9 into App-/-, Aplp2-/-, Aplp2-depleted App-/-, or liver-specific Lrp1-/- mice resulted in similar reductions in the levels of hepatic LDLR as seen in wild-type (WT) mice. Infusion of PCSK9 into WT mice also had no effect on the levels of hepatic APP, APLP2 or LRP1. Thus, APP, APLP2 and LRP1 are not required for PCSK9-mediated LDLR degradation and are not regulated by PCSK9 in vivo.
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Physiological and therapeutic regulation of PCSK9 activity in cardiovascular disease. Basic Res Cardiol 2017; 112:32. [PMID: 28439730 PMCID: PMC5403857 DOI: 10.1007/s00395-017-0619-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/07/2017] [Indexed: 12/14/2022]
Abstract
Ischemic heart disease is the main cause of death worldwide and is accelerated by increased levels of low-density lipoprotein cholesterol (LDL-C). Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a potent circulating regulator of LDL-C through its ability to induce degradation of the LDL receptor (LDLR) in the lysosome of hepatocytes. Only in the last few years, a number of breakthroughs in the understanding of PCSK9 biology have been reported illustrating how PCSK9 activity is tightly regulated at several levels by factors influencing its transcription, secretion, or by extracellular inactivation and clearance. Two humanized antibodies directed against the LDLR-binding site in PCSK9 received approval by the European and US authorities and additional PCSK9 directed therapeutics are climbing up the phases of clinical trials. The first outcome data of the PCSK9 inhibitor evolocumab reported a significant reduction in the composite endpoint (cardiovascular death, myocardial infarction, or stroke) and further outcome data are awaited. Meanwhile, it became evident that PCSK9 has (patho)physiological roles in several cardiovascular cells. In this review, we summarize and discuss the recent biological and clinical data on PCSK9, the regulation of PCSK9, its extra-hepatic activities focusing on cardiovascular cells, molecular concepts to target PCSK9, and finally briefly summarize the data of recent clinical studies.
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44
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Abstract
Ischemic heart disease is the main cause of death worldwide and it is accelerated by increased low-density lipoprotein (LDL) cholesterol (LDL-C) and/or lipoprotein (a) (Lp(a)) concentrations. Proprotein convertase subtilisin/kexin type 9 (PCSK9) alters both LDL-C and in part Lp(a) concentrations through its ability to induce degradation of the LDL receptor (LDLR). PCSK9, however, has additional targets which are potentially involved in lipid metabolism regulation such as the very low density lipoprotein receptor (VLDL), CD36 (cluster of differentiation 36) and the epithelial cholesterol transporter (NPC1L1) and it affects expression of apolipoprotein B48. The PCSK9 activity is tightly regulated at several levels by factors influencing its transcription, secretion, or by extracellular inactivation and clearance. Many comorbidities (kidney insufficiency, hypothyreoidism, hyperinsulinemia, inflammation) modify PCSK9 expression and release. Two humanized antibodies directed against extracellular PCSK9 received approval by the European and US authorities and additional PCSK9 directed therapeutics (such as silencing RNA) are already in clinical trials. Their results demonstrate a significant reduction in both LDL-C and Lp(a) concentrations – independent of the concomitant medication – and one of them reduced plaque size in high risk cardiovascular patients; results of two ongoing large clinical endpoints studies are awaited. In this review, we summarize and discuss the recent biological data on PCSK9, the regulation of PCSK9, and finally briefly summarize the data of recent clinical studies in the context of lipid metabolism.
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Affiliation(s)
- Rainer Schulz
- Department of Physiology, Justus-Liebig-Universität, Aulweg 129, 35392, Giessen, Germany.
| | - Klaus-Dieter Schlüter
- Department of Physiology, Justus-Liebig-Universität, Aulweg 129, 35392, Giessen, Germany
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45
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Dong H, Zhao Z, LeBrun DG, Michaely P. Identification of roles for H264, H306, H439, and H635 in acid-dependent lipoprotein release by the LDL receptor. J Lipid Res 2016; 58:364-374. [PMID: 27895090 DOI: 10.1194/jlr.m070938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/19/2016] [Indexed: 11/20/2022] Open
Abstract
Lipoproteins internalized by the LDL receptor (LDLR) are released from this receptor in endosomes through a process that involves acid-dependent conformational changes in the receptor ectodomain. How acidic pH promotes this release process is not well understood. Here, we assessed roles for six histidine residues for which either genetic or structural data suggested a possible role in the acid-responsiveness of the LDLR. Using assays that measured conformational change, acid-dependent lipoprotein release, LDLR recycling, and net lipoprotein uptake, we show that H635 plays important roles in acid-dependent conformational change and lipoprotein release, while H264, H306, and H439 play ancillary roles in the response of the LDLR to acidic pH.
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Affiliation(s)
- Hongyun Dong
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Zhenze Zhao
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Drake G LeBrun
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Peter Michaely
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
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46
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Pocoví M. [PCSK9 continues surprising us]. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS 2016; 28:79-81. [PMID: 27040976 DOI: 10.1016/j.arteri.2016.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 03/07/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Miguel Pocoví
- Departamento de Bioquímica, Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Instituto de Investigación Sanitaria de Aragón, Zaragoza, España.
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Ding Y, Xian X, Holland WL, Tsai S, Herz J. Low-Density Lipoprotein Receptor-Related Protein-1 Protects Against Hepatic Insulin Resistance and Hepatic Steatosis. EBioMedicine 2016; 7:135-45. [PMID: 27322467 PMCID: PMC4913705 DOI: 10.1016/j.ebiom.2016.04.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 11/15/2022] Open
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP1) is a multifunctional uptake receptor for chylomicron remnants in the liver. In vascular smooth muscle cells LRP1 controls reverse cholesterol transport through platelet-derived growth factor receptor β (PDGFR-β) trafficking and tyrosine kinase activity. Here we show that LRP1 regulates hepatic energy homeostasis by integrating insulin signaling with lipid uptake and secretion. Somatic inactivation of LRP1 in the liver (hLRP1KO) predisposes to diet-induced insulin resistance with dyslipidemia and non-alcoholic hepatic steatosis. On a high-fat diet, hLRP1KO mice develop a severe Metabolic Syndrome secondary to hepatic insulin resistance, reduced expression of insulin receptors on the hepatocyte surface and decreased glucose transporter 2 (GLUT2) translocation. While LRP1 is also required for efficient cell surface insulin receptor expression in the absence of exogenous lipids, this latent state of insulin resistance is unmasked by exposure to fatty acids. This further impairs insulin receptor trafficking and results in increased hepatic lipogenesis, impaired fatty acid oxidation and reduced very low density lipoprotein (VLDL) triglyceride secretion. Hepatic LRP1 deficiency in a mouse model (hLRP1KO) predisposes to diet-induced insulin resistance, dyslipidemia, and obesity. Insulin resistance in the hLRP1KO mouse results from reduced cell surface expression of insulin receptor (IR) and impaired translocation of glucose transporter 2 (GLUT2). Excess fatty acids in hLRP1KO mice shift hepatic fatty acid metabolism from an oxidative to a synthetic state, resulting in hepatic steatosis.
LRP1 is a multifunctional transmembrane receptor with essential functions in lipoprotein metabolism and subcellular receptor tyrosine kinase trafficking. A mouse model of hepatic LRP1 deficiency integrates the hallmark findings in Metabolic Syndrome - insulin resistance, dyslipidemia, and hepatic steatosis - with impaired glucose metabolism and altered hepatic fatty acid metabolism as a consequence of reduced insulin receptor trafficking and signaling. These findings underscore the central role of LRP1 in overall energy homeostasis, and specifically liver glucose and fatty acid metabolism.
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Affiliation(s)
- Yinyuan Ding
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, TX 75390, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical Center, Dallas, TX 75390, USA; Key Laboratory of Medical Electrophysiology, Ministry of Education of China, China; Institute of Cardiovascular Research, Sichuan Medical University, Luzhou 646000, China
| | - Xunde Xian
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, TX 75390, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| | - William L Holland
- Department of Internal Medicine, Touchstone Diabetes Center, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shirling Tsai
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA; Dallas VA Medical Center, Dallas, TX 75216, USA
| | - Joachim Herz
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, TX 75390, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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48
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A MARCH6 and IDOL E3 Ubiquitin Ligase Circuit Uncouples Cholesterol Synthesis from Lipoprotein Uptake in Hepatocytes. Mol Cell Biol 2015; 36:285-94. [PMID: 26527619 DOI: 10.1128/mcb.00890-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 10/27/2015] [Indexed: 11/20/2022] Open
Abstract
Cholesterol synthesis and lipoprotein uptake are tightly coordinated to ensure that the cellular level of cholesterol is adequately maintained. Hepatic dysregulation of these processes is associated with pathological conditions, most notably cardiovascular disease. Using a genetic approach, we have recently identified the E3 ubiquitin ligase MARCH6 as a regulator of cholesterol biosynthesis, owing to its ability to promote degradation of the rate-limiting enzymes 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR) and squalene epoxidase (SQLE). Here, we present evidence for MARCH6 playing a multifaceted role in the control of cholesterol homeostasis in hepatocytes. We identify MARCH6 as an endogenous inhibitor of the sterol regulatory element binding protein (SREBP) transcriptional program. Accordingly, loss of MARCH6 increases expression of SREBP-regulated genes involved in cholesterol biosynthesis and lipoprotein uptake. Unexpectedly, this is associated with a decrease in cellular lipoprotein uptake, induced by enhanced lysosomal degradation of the low-density lipoprotein receptor (LDLR). Finally, we provide evidence that induction of the E3 ubiquitin ligase IDOL represents the molecular mechanism underlying this MARCH6-induced phenotype. Our study thus highlights a MARCH6-dependent mechanism to direct cellular cholesterol accretion that relies on uncoupling of cholesterol synthesis from lipoprotein uptake.
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Demers A, Samami S, Lauzier B, Des Rosiers C, Ngo Sock ET, Ong H, Mayer G. PCSK9 Induces CD36 Degradation and Affects Long-Chain Fatty Acid Uptake and Triglyceride Metabolism in Adipocytes and in Mouse Liver. Arterioscler Thromb Vasc Biol 2015; 35:2517-25. [PMID: 26494228 DOI: 10.1161/atvbaha.115.306032] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/12/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes the degradation of the low-density lipoprotein receptor thereby elevating plasma low-density lipoprotein cholesterol levels and the risk of coronary heart disease. Thus, the use of PCSK9 inhibitors holds great promise to prevent heart disease. Previous work found that PCSK9 is involved in triglyceride metabolism, independently of its action on low-density lipoprotein receptor, and that other yet unidentified receptors could mediate this effect. Therefore, we assessed whether PCSK9 enhances the degradation of CD36, a major receptor involved in transport of long-chain fatty acids and triglyceride storage. APPROACH AND RESULTS Overexpressed or recombinant PCSK9 induced CD36 degradation in cell lines and primary adipocytes and reduced the uptake of the palmitate analog Bodipy FL C16 and oxidized low-density lipoprotein in 3T3-L1 adipocytes and hepatic HepG2 cells, respectively. Surface plasmon resonance, coimmunoprecipitation, confocal immunofluorescence microscopy, and protein degradation pathway inhibitors revealed that PCSK9 directly interacts with CD36 and targets the receptor to lysosomes through a mechanism involving the proteasome. Importantly, the level of CD36 protein was increased by >3-fold upon small interfering RNA knockdown of endogenous PCSK9 in hepatic cells and similarly increased in the liver and visceral adipose tissue of Pcsk9(-/-) mice. In Pcsk9(-/-) mice, increased hepatic CD36 was correlated with an amplified uptake of fatty acid and accumulation of triglycerides and lipid droplets. CONCLUSIONS Our results demonstrate an important role of PCSK9 in modulating the function of CD36 and triglyceride metabolism. PCSK9-mediated CD36 degradation may serve to limit fatty acid uptake and triglyceride accumulation in tissues, such as the liver.
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Affiliation(s)
- Annie Demers
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Samaneh Samami
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Benjamin Lauzier
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Christine Des Rosiers
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Emilienne Tudor Ngo Sock
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Huy Ong
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Gaetan Mayer
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada.
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Hopkins PN, Defesche J, Fouchier SW, Bruckert E, Luc G, Cariou B, Sjouke B, Leren TP, Harada-Shiba M, Mabuchi H, Rabès JP, Carrié A, van Heyningen C, Carreau V, Farnier M, Teoh YP, Bourbon M, Kawashiri MA, Nohara A, Soran H, Marais AD, Tada H, Abifadel M, Boileau C, Chanu B, Katsuda S, Kishimoto I, Lambert G, Makino H, Miyamoto Y, Pichelin M, Yagi K, Yamagishi M, Zair Y, Mellis S, Yancopoulos GD, Stahl N, Mendoza J, Du Y, Hamon S, Krempf M, Swergold GD. Characterization of Autosomal Dominant Hypercholesterolemia Caused by PCSK9 Gain of Function Mutations and Its Specific Treatment With Alirocumab, a PCSK9 Monoclonal Antibody. ACTA ACUST UNITED AC 2015; 8:823-31. [PMID: 26374825 PMCID: PMC5098466 DOI: 10.1161/circgenetics.115.001129] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 08/25/2015] [Indexed: 01/01/2023]
Abstract
BACKGROUND Patients with PCSK9 gene gain of function (GOF) mutations have a rare form of autosomal dominant hypercholesterolemia. However, data examining their clinical characteristics and geographic distribution are lacking. Furthermore, no randomized treatment study in this population has been reported. METHODS AND RESULTS We compiled clinical characteristics of PCSK9 GOF mutation carriers in a multinational retrospective, cross-sectional, observational study. We then performed a randomized placebo-phase, double-blind study of alirocumab 150 mg administered subcutaneously every 2 weeks to 13 patients representing 4 different PCSK9 GOF mutations with low-density lipoprotein cholesterol (LDL-C) ≥70 mg/dL on their current lipid-lowering therapies at baseline. Observational study: among 164 patients, 16 different PCSK9 GOF mutations distributed throughout the gene were associated with varying severity of untreated LDL-C levels. Coronary artery disease was common (33%; average age of onset, 49.4 years), and untreated LDL-C concentrations were higher compared with matched carriers of mutations in the LDLR (n=2126) or apolipoprotein B (n=470) genes. Intervention study: in PCSK9 GOF mutation patients randomly assigned to receive alirocumab, mean percent reduction in LDL-C at 2 weeks was 62.5% (P<0.0001) from baseline, 53.7% compared with placebo-treated PCSK9 GOF mutation patients (P=0.0009; primary end point). After all subjects received 8 weeks of alirocumab treatment, LDL-C was reduced by 73% from baseline (P<0.0001). CONCLUSIONS PCSK9 GOF mutation carriers have elevated LDL-C levels and are at high risk of premature cardiovascular disease. Alirocumab, a PCSK9 antibody, markedly lowers LDL-C levels and seems to be well tolerated in these patients. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01604824.
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