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Krauss RM, Lu JT, Higgins JJ, Clary CM, Tabibiazar R. VLDL receptor gene therapy for reducing atherogenic lipoproteins. Mol Metab 2023; 69:101685. [PMID: 36739970 PMCID: PMC9950951 DOI: 10.1016/j.molmet.2023.101685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/16/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Over the past 40 years, there has been considerable research into the management and treatment of atherogenic lipid disorders. Although the majority of treatments and management strategies for cardiovascular disease (CVD) center around targeting low-density lipoprotein cholesterol (LDL-C), there is mounting evidence for the residual CVD risk attributed to high triglyceride (TG) and lipoprotein(a) (Lp(a)) levels despite the presence of lowered LDL-C levels. Among the biological mechanisms for clearing TG-rich lipoproteins, the VLDL receptor (VLDLR) plays a key role in the trafficking and metabolism of lipoprotein particles in multiple tissues, but it is not ordinarily expressed in the liver. Since VLDLR is capable of binding and internalizing apoE-containing TG-rich lipoproteins as well as Lp(a), hepatic VLDLR expression has the potential for promoting clearance of these atherogenic particles from the circulation and managing the residual CVD risk not addressed by current lipid lowering therapies. This review provides an overview of VLDLR function and the potential for developing a genetic medicine based on liver-targeted VLDLR gene expression.
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Affiliation(s)
- Ronald M. Krauss
- University of California, San Francisco, 5700 Martin Luther King, Jr. Way, Oakland CA 94609, USA,Corresponding author.
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Huang JK, Lee HC. Emerging Evidence of Pathological Roles of Very-Low-Density Lipoprotein (VLDL). Int J Mol Sci 2022; 23:ijms23084300. [PMID: 35457118 PMCID: PMC9031540 DOI: 10.3390/ijms23084300] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 12/18/2022] Open
Abstract
Embraced with apolipoproteins (Apo) B and Apo E, triglyceride-enriched very-low-density lipoprotein (VLDL) is secreted by the liver into circulation, mainly during post-meal hours. Here, we present a brief review of the physiological role of VLDL and a systemic review of the emerging evidence supporting its pathological roles. VLDL promotes atherosclerosis in metabolic syndrome (MetS). VLDL isolated from subjects with MetS exhibits cytotoxicity to atrial myocytes, induces atrial myopathy, and promotes vulnerability to atrial fibrillation. VLDL levels are affected by a number of endocrinological disorders and can be increased by therapeutic supplementation with cortisol, growth hormone, progesterone, and estrogen. VLDL promotes aldosterone secretion, which contributes to hypertension. VLDL induces neuroinflammation, leading to cognitive dysfunction. VLDL levels are also correlated with chronic kidney disease, autoimmune disorders, and some dermatological diseases. The extra-hepatic secretion of VLDL derived from intestinal dysbiosis is suggested to be harmful. Emerging evidence suggests disturbed VLDL metabolism in sleep disorders and in cancer development and progression. In addition to VLDL, the VLDL receptor (VLDLR) may affect both VLDL metabolism and carcinogenesis. Overall, emerging evidence supports the pathological roles of VLDL in multi-organ diseases. To better understand the fundamental mechanisms of how VLDL promotes disease development, elucidation of the quality control of VLDL and of the regulation and signaling of VLDLR should be indispensable. With this, successful VLDL-targeted therapies can be discovered in the future.
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Affiliation(s)
- Jih-Kai Huang
- Department of General Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Hsiang-Chun Lee
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Lipid Science and Aging Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80708, Taiwan
- Graduate Institute of Animal Vaccine Technology, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Correspondence: ; Tel.: +886-7-3121101 (ext. 7741)
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Luquero A, Vilahur G, Casani L, Badimon L, Borrell-Pages M. Differential cholesterol uptake in liver cells: A role for PCSK9. FASEB J 2022; 36:e22291. [PMID: 35344222 DOI: 10.1096/fj.202101660rr] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/11/2022] [Accepted: 03/20/2022] [Indexed: 12/21/2022]
Abstract
The clearance of low-density lipoprotein (LDL) particles from the circulation is regulated by the LDL receptor (LDLR) and proprotein convertase subtilisin/kexin 9 (PCSK9) interaction. Its disruption reduces blood cholesterol levels and delays atherosclerosis progression. Whether other members of the LDLR superfamily are in vivo targets of PCSK9 has been poorly explored. The aim of this work was to study the interaction between PCSK9 and members of the LDLR superfamily in the regulation of liver cholesterol homeostasis in an in vivo low-density lipoprotein receptor related protein 5 (LRP5) deficient mice model challenged with high-fat diet. Our results show that Wt and Lrp5-/- mice fed a hypercholesterolemic diet (HC) have increased cholesterol ester accumulation and decreased liver LDLR and LRP5 gene and protein expression. Very low-density lipoprotein receptor (VLDLR), LRP6, LRP2, and LRP1 expression levels were analyzed in liver samples and show that they do not participate in Lrp5-/- liver cholesterol uptake. Immunoprecipitation experiments show that LRP5 forms a complex with PCSK9 in liver-specific fat-storing stellate cells but not in structural HepG2 cells. Hepatic stellate cells silenced for LRP5 and/or PCSK9 expression and challenged with lipids show reduced cholesterol ester accumulation, indicating that both proteins are involved in lipid processing in the liver. Our results indicate that cholesterol esters accumulate in livers of Wt mice in a LDLR-family-members dependent manner as VLDLR, LRP2, and LRP6 show increased expression in HC mice. However, this increase is lost in livers of Lrp5-/- mice, where scavenger receptors are involved in cholesterol uptake. PCSK9 expression is strongly downregulated in mice livers after HC feeding. However PCSK9 and LRP5 bind in the cytoplasm of fat storing liver cells, indicating that this PCSK9-LRP5 interaction is cell-type specific and that both proteins contribute to lipid uptake.
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Affiliation(s)
- Aureli Luquero
- Cardiovascular Program ICCC, Hospital de la Santa Creu i Sant Pau Research Institute, IIB-Sant Pau, Barcelona, Spain
| | - Gemma Vilahur
- Cardiovascular Program ICCC, Hospital de la Santa Creu i Sant Pau Research Institute, IIB-Sant Pau, Barcelona, Spain.,CIBER-CV, Instituto de Salud Carlos III, Spain
| | - Laura Casani
- Cardiovascular Program ICCC, Hospital de la Santa Creu i Sant Pau Research Institute, IIB-Sant Pau, Barcelona, Spain
| | - Lina Badimon
- Cardiovascular Program ICCC, Hospital de la Santa Creu i Sant Pau Research Institute, IIB-Sant Pau, Barcelona, Spain.,CIBER-CV, Instituto de Salud Carlos III, Spain.,Cardiovascular Research Chair, UAB, Barcelona, Spain
| | - Maria Borrell-Pages
- Cardiovascular Program ICCC, Hospital de la Santa Creu i Sant Pau Research Institute, IIB-Sant Pau, Barcelona, Spain.,CIBER-CV, Instituto de Salud Carlos III, Spain
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Rodriguez-Calvo R, Masana L. Review of the scientific evolution of gene therapy for the treatment of homozygous familial hypercholesterolaemia: past, present and future perspectives. J Med Genet 2019; 56:711-717. [DOI: 10.1136/jmedgenet-2018-105713] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/12/2019] [Accepted: 02/16/2019] [Indexed: 11/03/2022]
Abstract
Familial hypercholesterolaemia (FH) is a devastating genetic disease that leads to extremely high cholesterol levels and severe cardiovascular disease, mainly caused by mutations in any of the main genes involved in low-density lipoprotein cholesterol (LDL-C) uptake. Among these genes, mutations in the LDL receptor (LDLR) are responsible for 80%–90% of the FH cases. The severe homozygous variety (HoFH) is not successfully treated with standard cholesterol-lowering therapies, and more aggressive strategies must be considered to mitigate the effects of this disease, such as weekly/biweekly LDL apheresis. However, development of new therapeutic approaches is needed to cure HoFH. Because HoFH is mainly due to mutations in theLDLR, this disease has been proposed as an ideal candidate for gene therapy. Several preclinical studies have proposed that the transference of functional copies of theLDLRgene reduces circulating LDL-C levels in several models of HoFH, which has led to the first clinical trials in humans. Additionally, the recent development of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 technology for genome editing has opened the door to therapies aimed at directly correcting the specific mutation in the endogenousLDLRgene. In this article, we review the genetic basis of the FH disease, paying special attention to the severe HoFH as well as the challenges in its diagnosis and clinical management. Additionally, we discuss the current therapies for this disease and the new emerging advances in gene therapy to target a definitive cure for this disease.
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Effects of Pharmacological Thermogenic Adipocyte Activation on Metabolism and Atherosclerotic Plaque Regression. Nutrients 2019; 11:nu11020463. [PMID: 30813320 PMCID: PMC6412269 DOI: 10.3390/nu11020463] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 02/14/2019] [Accepted: 02/18/2019] [Indexed: 11/16/2022] Open
Abstract
Thermogenic adipocytes burn nutrients in order to produce heat. Upon activation, brown adipose tissue (BAT) clears vast amounts of lipids and glucose from the circulation and thus substantially lowers plasma lipid levels. As a consequence, BAT activation protects from the development of atherosclerosis. However, it is unclear if pharmacologic activation of BAT can be exploited therapeutically to reduce plaque burden in established atherosclerotic disease. Here we study the impact of thermogenic adipose tissues on plaque regression in a mouse model of atherosclerosis. Thermogenic adipocytes in atherosclerotic low-density lipoprotein (LDL) receptor (LDLR)-deficient mice were pharmacologically activated by dietary CL316,243 (CL) treatment for 4 weeks and the outcomes on metabolically active tissues, plasma lipids and atherosclerosis were analyzed. While the chronic activation of thermogenic adipocytes reduced adiposity, increased browning of white adipose tissue (WAT), altered liver gene expression, and reduced plasma triglyceride levels, atherosclerotic plaque burden remained unchanged. Our findings suggest that despite improving adiposity and plasma triglycerides, pharmacologic activation of thermogenic adipocytes is not able to reverse atherosclerosis in LDLR-deficient mice.
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Canet-Pons J, Schubert R, Duecker RP, Schrewe R, Wölke S, Kieslich M, Schnölzer M, Chiocchetti A, Auburger G, Zielen S, Warnken U. Ataxia telangiectasia alters the ApoB and reelin pathway. Neurogenetics 2018; 19:237-255. [DOI: 10.1007/s10048-018-0557-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023]
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The Reelin Receptors Apolipoprotein E receptor 2 (ApoER2) and VLDL Receptor. Int J Mol Sci 2018; 19:ijms19103090. [PMID: 30304853 PMCID: PMC6213145 DOI: 10.3390/ijms19103090] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/03/2018] [Accepted: 10/03/2018] [Indexed: 01/28/2023] Open
Abstract
Apolipoprotein E receptor 2 (ApoER2) and VLDL receptor belong to the low density lipoprotein receptor family and bind apolipoprotein E. These receptors interact with the clathrin machinery to mediate endocytosis of macromolecules but also interact with other adapter proteins to perform as signal transduction receptors. The best characterized signaling pathway in which ApoER2 and VLDL receptor (VLDLR) are involved is the Reelin pathway. This pathway plays a pivotal role in the development of laminated structures of the brain and in synaptic plasticity of the adult brain. Since Reelin and apolipoprotein E, are ligands of ApoER2 and VLDLR, these receptors are of interest with respect to Alzheimer’s disease. We will focus this review on the complex structure of ApoER2 and VLDLR and a recently characterized ligand, namely clusterin.
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Rahman K, Fisher EA. Insights From Pre-Clinical and Clinical Studies on the Role of Innate Inflammation in Atherosclerosis Regression. Front Cardiovasc Med 2018; 5:32. [PMID: 29868610 PMCID: PMC5958627 DOI: 10.3389/fcvm.2018.00032] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 03/20/2018] [Indexed: 12/11/2022] Open
Abstract
Atherosclerosis, the underlying cause of coronary artery (CAD) and other cardiovascular diseases, is initiated by macrophage-mediated immune responses to lipoprotein and cholesterol accumulation in artery walls, which result in the formation of plaques. Unlike at other sites of inflammation, the immune response becomes maladaptive and inflammation fails to resolve. The most common treatment for reducing the risk from atherosclerosis is low density lipoprotein cholesterol (LDL-C) lowering. Studies have shown, however, that while significant lowering of LDL-C reduces the risk of heart attacks to some degree, there is still residual risk for the majority of the population. We and others have observed “residual inflammatory risk” of atherosclerosis after plasma cholesterol lowering in pre-clinical studies, and that this phenomenon is clinically relevant has been dramatically reinforced by the recent Canakinumab Anti-inflammatory Thrombosis Outcomes Study (CANTOS) trial. This review will summarize the role of the innate immune system, specifically macrophages, in atherosclerosis progression and regression, as well as the pre-clinical and clinical models that have provided significant insights into molecular pathways involved in the resolution of plaque inflammation and plaque regression. Partnered with clinical studies that can be envisioned in the post-CANTOS period, including progress in developing targeted plaque therapies, we expect that pre-clinical studies advancing on the path summarized in this review, already revealing key mechanisms, will continue to be essential contributors to achieve the goals of dampening plaque inflammation and inducing its resolution in order to maximize the therapeutic benefits of conventional risk factor modifications, such as LDL-C lowering.
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Affiliation(s)
- Karishma Rahman
- Department of Medicine, Division of Cardiology, New York University School of Medicine, New York, NY, United States
| | - Edward A Fisher
- Department of Medicine, Division of Cardiology, New York University School of Medicine, New York, NY, United States
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Yang JH, Cho SS, Kim KM, Kim JY, Kim EJ, Park EY, Lee JH, Ki SH. Neoagarooligosaccharides enhance the level and efficiency of LDL receptor and improve cholesterol homeostasis. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.09.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Ponziani FR, Pecere S, Gasbarrini A, Ojetti V. Physiology and pathophysiology of liver lipid metabolism. Expert Rev Gastroenterol Hepatol 2016; 9:1055-67. [PMID: 26070860 DOI: 10.1586/17474124.2015.1056156] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Liver lipid metabolism and its modulation are involved in many pathologic conditions, such as obesity, non-alcoholic fatty liver disease, diabetes mellitus, atherosclerosis and cardiovascular disease. Metabolic disorders seem to share a similar background of low-grade chronic inflammation, even if the pathophysiological mechanisms leading to tissue and organ damage have not been completely clarified yet. The accumulation of neutral lipids in the liver is now recognized as a beneficial and protective mechanism; on the other hand, lipoperoxidation is involved in the development and progression of non-alcoholic steatohepatitis. The role of the gut microbiota in liver lipid metabolism has been the object of recent scientific investigations. It is likely that the gut microbiota is involved in a complex metabolic modulation and the translocation of gut microflora may also contribute to maintaining the low-grade inflammatory status of metabolic syndrome. Therefore, lipid metabolism pathology has vague limits and complex mechanisms, and the knowledge of these is essential to guide diagnostic and therapeutic decisions.
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Sleeping Beauty Transposon Vectors in Liver-directed Gene Delivery of LDLR and VLDLR for Gene Therapy of Familial Hypercholesterolemia. Mol Ther 2015; 24:620-35. [PMID: 26670130 DOI: 10.1038/mt.2015.221] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/04/2015] [Indexed: 01/12/2023] Open
Abstract
Plasmid-based Sleeping Beauty (SB) transposon vectors were developed and used to deliver genes for low-density lipoprotein and very-low-density lipoprotein receptors (LDLR and VLDLR, respectively) or lacZ reporter into liver of an LDLR-deficient mouse model of familial hypercholesterolemia (FH). SB transposase, SB100x, was used to integrate the therapeutic transposons into mice livers for evaluating the feasibility of the vectors in reducing high blood cholesterol and the progression of atherosclerosis. Hydrodynamic gene delivery of transposon-VLDLR into the livers of the mice resulted in initial 17-19% reductions in plasma cholesterol, and at the later time points, in a significant stabilization of the cholesterol level for the 6.5-month duration of the study compared to the control mice. Transposon-LDLR-treated animals also demonstrated a trend of stabilization in the cholesterol levels in the long term. Vector-treated mice had slightly less lipid accumulation in the liver and reduced aortic atherosclerosis. Clinical chemistry and histological analyses revealed normal liver function and morphology comparable to that of the controls during the follow-up with no safety issues regarding the vector type, transgenes, or the gene transfer method. The study demonstrates the safety and potential benefits of the SB transposon vectors in the treatment of FH.
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Borrell‐Pages M, Carolina Romero J, Badimon L. LRP5 and plasma cholesterol levels modulate the canonical Wnt pathway in peripheral blood leukocytes. Immunol Cell Biol 2015; 93:653-61. [DOI: 10.1038/icb.2015.41] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 01/05/2015] [Accepted: 01/28/2015] [Indexed: 02/02/2023]
Affiliation(s)
- Maria Borrell‐Pages
- Cardiovascular Research Center, CSIC‐ICCC, Hospital de la Santa Creu i Sant Pau, IIB‐Sant Pau Barcelona Spain
- Cardiovascular Research Chair, UAB Barcelona Spain
| | - July Carolina Romero
- Cardiovascular Research Center, CSIC‐ICCC, Hospital de la Santa Creu i Sant Pau, IIB‐Sant Pau Barcelona Spain
- Cardiovascular Research Chair, UAB Barcelona Spain
| | - Lina Badimon
- Cardiovascular Research Center, CSIC‐ICCC, Hospital de la Santa Creu i Sant Pau, IIB‐Sant Pau Barcelona Spain
- Cardiovascular Research Chair, UAB Barcelona Spain
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Kolovou G, Vasiliadis I, Gontoras N, Kolovou V, Hatzigeorgiou G. Microsomal Transfer Protein Inhibitors, New Approach for Treatment of Familial Hypercholesterolemia, Review of the Literature, Original Findings, and Clinical Significance. Cardiovasc Ther 2015; 33:71-8. [DOI: 10.1111/1755-5922.12105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Genovefa Kolovou
- Cardiology Department; Onassis Cardiac Surgery Center; Athens Greece
| | - Ioannis Vasiliadis
- Cardiology Department; Onassis Cardiac Surgery Center; Athens Greece
- Cardiology Department; Royal Free Hospital; London UK
| | - Nikos Gontoras
- Cardiology Department; Onassis Cardiac Surgery Center; Athens Greece
| | - Vana Kolovou
- Cardiology Department; Onassis Cardiac Surgery Center; Athens Greece
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Kim SK, Sun B, Yoon H, Lee JH, Lee G, Sohn SH, Kim H, Quan FS, Shim I, Ha J, Min BI, Bae H. Expression levels of the hypothalamic AMPK gene determines the responsiveness of the rats to electroacupuncture-induced analgesia. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 14:211. [PMID: 24980520 PMCID: PMC4096532 DOI: 10.1186/1472-6882-14-211] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/25/2014] [Indexed: 01/10/2023]
Abstract
BACKGROUND Although electroacupuncture (EA) relieves various types of pain, individual differences in the sensitivity to EA analgesia have been reported, causing experimental and clinical difficulties. Our functional genomic study using cDNA microarray identified that 5'-AMP-activated protein kinase (AMPK), a well-known factor in the regulation of energy homeostasis, is the most highly expressed gene in the hypothalamus of the rats that were sensitive to EA analgesia ("responder"), as compared to the rats that were insensitive to EA analgesia ("non-responder"). In this study, we investigated the causal relationship between the hypothalamic AMPK and the individual variation in EA analgesia. METHODS Sprague-Dawley (SD) rats were divided into the responder and the non-responder groups, based on EA-induced analgesic effects in the tail flick latency (TFL) test, which measures the latency of the tail flick response elicited by radiant heat applied to the tail. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was performed to quantify the expression levels of AMPK mRNA in the hypothalamus of the responder and non-responder rats. Further, we examined whether viral manipulation of the AMPK expression in the hypothalamus modulates EA analgesia in rats. RESULTS The real-time RT-PCR analysis showed that mRNA expression levels of AMPK in the hypothalamus of the responder rats are significantly higher than those of the non-responder rats, validating the previous microarray results. Microinjection of dominant negative (DN) AMPK adenovirus, which inhibits AMPK activity, into the rat hypothalamus significantly attenuates EA analgesia (p < 0.05), whereas wild type (WT) AMPK virus did not affect EA analgesia (p > 0.05). CONCLUSIONS The present results demonstrated that levels of AMPK gene expression in the rat hypothalamus determine the individual differences in the sensitivity to EA analgesia. Thus, our findings provide a clinically useful evidence for the application of acupuncture or EA for analgesia.
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Affiliation(s)
- Sun Kwang Kim
- Department of Physiology, College of Korean Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Boram Sun
- Department of East-West Medicine, Graduate School, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Heera Yoon
- Department of Physiology, College of Korean Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Ji Hwan Lee
- Department of Physiology, College of Korean Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
- Department of Microbiology, Pusan National University, 609-735 Busan, Republic of Korea
| | - Giseog Lee
- Department of Physiology, College of Korean Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
- Department of East-West Medicine, Graduate School, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Sung-Hwa Sohn
- Department of Physiology, College of Korean Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
- Department of Physiology, School of Medicine, Ajou University, 443-721 Suwon, Republic of Korea
| | - Hyunseong Kim
- Department of Physiology, College of Korean Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Fu Shi Quan
- Department of Medical Zoology, School of Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Insop Shim
- Acupuncture & Meridian Science Research Center, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Joohun Ha
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Byung-Il Min
- Department of East-West Medicine, Graduate School, Kyung Hee University, 130-701 Seoul, Republic of Korea
- Department of Physiology, School of Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
| | - Hyunsu Bae
- Department of Physiology, College of Korean Medicine, Kyung Hee University, 130-701 Seoul, Republic of Korea
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Znf202 affects high density lipoprotein cholesterol levels and promotes hepatosteatosis in hyperlipidemic mice. PLoS One 2013; 8:e57492. [PMID: 23469003 PMCID: PMC3585336 DOI: 10.1371/journal.pone.0057492] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/22/2013] [Indexed: 11/19/2022] Open
Abstract
Background The zinc finger protein Znf202 is a transcriptional suppressor of lipid related genes and has been linked to hypoalphalipoproteinemia. A functional role of Znf202 in lipid metabolism in vivo still remains to be established. Methodology and Principal Findings We generated mouse Znf202 expression vectors, the functionality of which was established in several in vitro systems. Next, effects of adenoviral znf202 overexpression in vivo were determined in normo- as well as hyperlipidemic mouse models. Znf202 overexpression in mouse hepatoma cells mhAT3F2 resulted in downregulation of members of the Apoe/c1/c2 and Apoa1/c3/a4 gene cluster. The repressive activity of Znf202 was firmly confirmed in an apoE reporter assay and Znf202 responsive elements within the ApoE promoter were identified. Adenoviral Znf202 transfer to Ldlr−/− mice resulted in downregulation of apoe, apoc1, apoa1, and apoc3 within 24 h after gene transfer. Interestingly, key genes in bile flux (abcg5/8 and bsep) and in bile acid synthesis (cyp7a1) were also downregulated. At 5 days post-infection, the expression of the aforementioned genes was normalized, but mice had developed severe hepatosteatosis accompanied by hypercholesterolemia and hypoalphalipoproteinemia. A much milder phenotype was observed in wildtype mice after 5 days of hepatic Znf202 overexpression. Interestingly and similar to Ldl−/− mice, HDL-cholesterol levels in wildtype mice were lowered after hepatic Znf202 overexpression. Conclusion/Significance Znf202 overexpression in vivo reveals an important role of this transcriptional regulator in liver lipid homeostasis, while firmly establishing the proposed key role in the control of HDL levels.
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Johnson LA, Arbones-Mainar JM, Fox RG, Pendse AA, Altenburg MK, Kim HS, Maeda N. Apolipoprotein E4 exaggerates diabetic dyslipidemia and atherosclerosis in mice lacking the LDL receptor. Diabetes 2011; 60:2285-94. [PMID: 21810592 PMCID: PMC3161311 DOI: 10.2337/db11-0466] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 06/29/2011] [Indexed: 11/29/2022]
Abstract
OBJECTIVE We investigated the differential roles of apolipoprotein E (apoE) isoforms in modulating diabetic dyslipidemia-a potential cause of the increased cardiovascular disease risk of patients with diabetes. RESEARCH DESIGN AND METHODS Diabetes was induced using streptozotocin (STZ) in human apoE3 (E3) or human apoE4 (E4) mice deficient in the LDL receptor (LDLR(-/-)). RESULTS Diabetic E3LDLR(-/-) and E4LDLR(-/-) mice have indistinguishable levels of plasma glucose and insulin. Despite this, diabetes increased VLDL triglycerides and LDL cholesterol in E4LDLR(-/-) mice twice as much as in E3LDLR(-/-) mice. Diabetic E4LDLR(-/-) mice had similar lipoprotein fractional catabolic rates compared with diabetic E3LDLR(-/-) mice but had larger hepatic fat stores and increased VLDL secretion. Diabetic E4LDLR(-/-) mice demonstrated a decreased reliance on lipid as an energy source based on indirect calorimetry. Lower phosphorylated acetyl-CoA carboxylase content and higher gene expression of fatty acid synthase in the liver indicated reduced fatty acid oxidation and increased fatty acid synthesis. E4LDLR(-/-) primary hepatocytes cultured in high glucose accumulated more intracellular lipid than E3LDLR(-/-) hepatocytes concomitant with a 60% reduction in fatty acid oxidation. Finally, the exaggerated dyslipidemia in diabetic E4LDLR(-/-) mice was accompanied by a dramatic increase in atherosclerosis. CONCLUSIONS ApoE4 causes severe dyslipidemia and atherosclerosis independent of its interaction with LDLR in a model of STZ-induced diabetes. ApoE4-expressing livers have reduced fatty acid oxidation, which contributes to the accumulation of tissue and plasma lipids.
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Affiliation(s)
- Lance A. Johnson
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jose M. Arbones-Mainar
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Raymond G. Fox
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Avani A. Pendse
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Michael K. Altenburg
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Hyung-Suk Kim
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Nobuyo Maeda
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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17
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Kwon BS, Jeong JS, Won YS, Lee CH, Yoon KS, Hyung Jung M, Kim IH, Lee SW. Intracellular efficacy of tumor-targeting group I intron-based trans-splicing ribozyme. J Gene Med 2011; 13:89-100. [PMID: 21322101 DOI: 10.1002/jgm.1545] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Group I intron-based trans-splicing ribozyme, which can specifically reprogram human telomerase reverse transcriptase (hTERT) RNA, could be a useful tool for tumor-targeted gene therapy. In the present study, the therapeutic feasibility of this ribozyme was investigated by analyzing trans-splicing efficacy in vivo as well as in cells. METHODS We assessed transgene activation, degree of ribozyme expression, targeted hTERT mRNA level, or the level of trans-splicing products in hTERT(+) cells or in human tumor nodules xenografted in animals after ribozyme administration. RESULTS The activity and efficacy of the trans-splicing ribozyme in cells was dependent on the amount of endogenous hTERT mRNA and/or the accumulation of ribozyme RNA in cells. Intracellular activity of the ribozyme reached a plateau when no more targetable substrate mRNA was available or the ribozyme RNA level was fully saturated. In addition, the efficacy of ribozyme in xenografted tumor tissues was dependent on the dose of the delivered ribozyme-encoding adenoviral vector, indicating the potential of the ribozyme expression level as a determining factor for the in vivo efficacy of the trans-splicing ribozyme. On the basis of these results, we enhanced the intracellular ribozyme activity by increasing the ribozyme expression level transcriptionally and/or post-transcriptionally. CONCLUSIONS We analyzed ribozyme efficacy and determined the most influential factors of its trans-splicing reaction in mammalian cell lines as well as in vivo. The present study could provide insights into the optimization of the trans-splicing ribozyme-based RNA replacement approach to cancer treatment.
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Affiliation(s)
- Byung-Su Kwon
- Department of Molecular Biology, Dankook University, Yongin, Korea
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18
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Rosales C, Tang D, Gillard BK, Courtney HS, Pownall HJ. Apolipoprotein E mediates enhanced plasma high-density lipoprotein cholesterol clearance by low-dose streptococcal serum opacity factor via hepatic low-density lipoprotein receptors in vivo. Arterioscler Thromb Vasc Biol 2011; 31:1834-41. [PMID: 21597008 DOI: 10.1161/atvbaha.111.224360] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Recombinant streptococcal serum opacity factor (rSOF) mediates the in vitro disassembly of human plasma high-density lipoprotein (HDL) into lipid-free apolipoprotein (apo) A-I, a neo-HDL that is cholesterol poor, and a cholesteryl ester-rich microemulsion (CERM) containing apoE. Given the occurrence of apoE on the CERM, we tested the hypothesis that rSOF injection into mice would reduce total plasma cholesterol clearance via apoE-dependent hepatic low-density lipoprotein receptors (LDLR). METHODS AND RESULTS rSOF (4 μg) injection into wild-type C57BL/6J mice formed neo-HDL, CERM, and lipid-free apoA-I, as observed in vitro, and reduced plasma total cholesterol (-43%, t(1/2)=44±18 minutes) whereas control saline injections had a negligible effect. Similar experiments with apoE(-/-) and LDLR(-/-) mice reduced plasma total cholesterol ≈0% and 20%, respectively. rSOF was potent; injection of 0.18 μg of rSOF produced 50% of maximum reduction of plasma cholesterol 3 hours postinjection, corresponding to a ≈0.5-mg human dose. Most cholesterol was cleared hepatically (>99%), with rSOF treatment increasing clearance by 65%. CONCLUSIONS rSOF injection into mice formed a CERM that was cleared via hepatic LDLR that recognize apoE. This reaction could provide an alternative mechanism for reverse cholesterol transport.
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Affiliation(s)
- Corina Rosales
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
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19
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Kolovou GD, Kostakou PM, Anagnostopoulou KK. Familial hypercholesterolemia and triglyceride metabolism. Int J Cardiol 2011; 147:349-58. [DOI: 10.1016/j.ijcard.2010.08.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 06/24/2010] [Accepted: 08/08/2010] [Indexed: 12/14/2022]
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20
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Yuan G, Liu Y, Sun T, Xu Y, Zhang J, Yang Y, Zhang M, Cianflone K, Wang DW. The Therapeutic Role of Very Low-Density Lipoprotein Receptor Gene in Hyperlipidemia in Type 2 Diabetic Rats. Hum Gene Ther 2011; 22:302-12. [PMID: 21087152 DOI: 10.1089/hum.2010.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Gang Yuan
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Yongjian Liu
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
- Department of Endocrinology, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Tingting Sun
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Yongping Xu
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Jianhuan Zhang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Yan Yang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Muxun Zhang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Katherine Cianflone
- Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
| | - Dao Wen Wang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
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21
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Barclay JL, Nelson CN, Ishikawa M, Murray LA, Kerr LM, McPhee TR, Powell EE, Waters MJ. GH-dependent STAT5 signaling plays an important role in hepatic lipid metabolism. Endocrinology 2011; 152:181-92. [PMID: 21084450 DOI: 10.1210/en.2010-0537] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
GH deficiency is known to be clinically associated with a high incidence of nonalcoholic fatty liver disease, and this can be reversed by GH administration. Here we investigated the mechanistic basis for this phenomenon using engineered male mice lacking different signaling elements of the GH receptor, hepatic stat5a/b(-/-) mice and a mouse hepatoma line. We found deficient GH-dependent signal transducer and activator of transcription (STAT)-5 signaling correlates with steatosis, and through microarray analysis, quantitative PCR, and chromatin immunoprecipitation, identified putative targets of STAT5 signaling responsible for the steatosis seen on a normal diet. These targets were verified with liver-specific stat5a/b deletion in vivo, and in vitro we show that dominant-negative (DN) STAT5 increases lipid uptake in a mouse hepatoma line. Because loss of STAT5 signaling results in elevated STAT1 and STAT3 activity and intracellular lipid accumulation, we have used DN-STAT5a/b, DN-STAT1, constitutively active (CA)-STAT3, or addition of oleate/palmitate in the hepatoma line to assign which of these apply to individual targets in STAT5 signaling deficiency. These findings and published mouse models of steatosis enable us to propose elevated cd36, pparγ, and pgc1α/β expression as primary instigators of the steatosis along with elevated fatty acid synthase, lipoprotein lipase, and very low-density lipoprotein receptor expression. Decreased fgf21 and insig2 expression may also contribute. In conclusion, despite normal plasma free fatty acids and minimal obesity, absent GH activation leads to steatosis because activated STAT5 prevents hepatic steatosis. These results raise the possibility of low-dose GH treatment for nonalcoholic fatty liver disease.
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Affiliation(s)
- Johanna L Barclay
- Institute for Molecular Bioscience, University of Queensland, Woolloongabba 4102, Australia
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22
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Al-Allaf FA, Coutelle C, Waddington SN, David AL, Harbottle R, Themis M. LDLR-Gene therapy for familial hypercholesterolaemia: problems, progress, and perspectives. Int Arch Med 2010; 3:36. [PMID: 21144047 PMCID: PMC3016243 DOI: 10.1186/1755-7682-3-36] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 12/13/2010] [Indexed: 12/03/2022] Open
Abstract
Coronary artery diseases (CAD) inflict a heavy economical and social burden on most populations and contribute significantly to their morbidity and mortality rates. Low-density lipoprotein receptor (LDLR) associated familial hypercholesterolemia (FH) is the most frequent Mendelian disorder and is a major risk factor for the development of CAD. To date there is no cure for FH. The primary goal of clinical management is to control hypercholesterolaemia in order to decrease the risk of atherosclerosis and to prevent CAD. Permanent phenotypic correction with single administration of a gene therapeutic vector is a goal still needing to be achieved. The first ex vivo clinical trial of gene therapy in FH was conducted nearly 18 years ago. Patients who had inherited LDLR gene mutations were subjected to an aggressive surgical intervention involving partial hepatectomy to obtain the patient's own hepatocytes for ex vivo gene transfer with a replication deficient LDLR-retroviral vector. After successful re-infusion of transduced cells through a catheter placed in the inferior mesenteric vein at the time of liver resection, only low-level expression of the transferred LDLR gene was observed in the five patients enrolled in the trial. In contrast, full reversal of hypercholesterolaemia was later demonstrated in in vivo preclinical studies using LDLR-adenovirus mediated gene transfer. However, the high efficiency of cell division independent gene transfer by adenovirus vectors is limited by their short-term persistence due to episomal maintenance and the cytotoxicity of these highly immunogenic viruses. Novel long-term persisting vectors derived from adeno-associated viruses and lentiviruses, are now available and investigations are underway to determine their safety and efficiency in preparation for clinical application for a variety of diseases. Several novel non-viral based therapies have also been developed recently to lower LDL-C serum levels in FH patients. This article reviews the progress made in the 18 years since the first clinical trial for gene therapy of FH, with emphasis on the development, design, performance and limitations of viral based gene transfer vectors used in studies to ameliorate the effects of LDLR deficiency.
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Affiliation(s)
- Faisal A Al-Allaf
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Al-Abedia Campus, P, O, Box 715, Makkah 21955, Saudi Arabia.
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23
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Nemati MH, Astaneh B. Optimal management of familial hypercholesterolemia: treatment and management strategies. Vasc Health Risk Manag 2010; 6:1079-88. [PMID: 21191428 PMCID: PMC3004511 DOI: 10.2147/vhrm.s8283] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Indexed: 01/17/2023] Open
Abstract
Familial hypercholesterolemia is an autosomally dominant disorder caused by various mutations in low-density lipoprotein receptor genes. This will lead to elevated levels of total and low-density lipoprotein cholesterol, which may in turn lead to premature coronary atherosclerosis and cardiac-related death. The symptoms are more severe in the homozygous type of the disease. Different options for the treatment of affected patients are now available. Diet therapy, pharmacologic therapy, lipid apheresis, and liver transplantation are among the various treatments. We clinically review the treatment and management strategies for the disease in order to shed light on the optimal management of familial hypercholesterolemia.
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24
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Asgari S, Pournasr B, Salekdeh GH, Ghodsizadeh A, Ott M, Baharvand H. Induced pluripotent stem cells: a new era for hepatology. J Hepatol 2010; 53:738-51. [PMID: 20621379 DOI: 10.1016/j.jhep.2010.05.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2010] [Revised: 05/09/2010] [Accepted: 05/13/2010] [Indexed: 12/17/2022]
Abstract
Stem cell transplantation has been proposed as an attractive alternative approach to restore liver mass and function. Recent progress has been reported on the generation of induced pluripotent stem (iPS) cells from somatic cells. Human-iPS cells can be differentiated towards the hepatic lineage which presents possibilities for improving research on diseases, drug development, tissue engineering, the development of bio-artificial livers, and a foundation for producing autologous cell therapies that would avoid immune rejection and enable correction of gene defects prior to cell transplantation. This focused review will discuss how human iPS cell advances are likely to have an impact on hepatology.
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Affiliation(s)
- Samira Asgari
- Department of Stem Cells and Developmental Biology, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
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25
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Stapleton PA, Goodwill AG, James ME, D'Audiffret AC, Frisbee JC. Differential impact of familial hypercholesterolemia and combined hyperlipidemia on vascular wall and network remodeling in mice. Microcirculation 2010; 17:47-58. [PMID: 20141600 DOI: 10.1111/j.1549-8719.2009.00003.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Genetic familial hypercholesterolemia (FH) and combined hyperlipidemia (FCH) are characterized by elevated plasma low-density lipoprotein (LDL) (FH) and LDL/triglycerides (FCH), with mouse models represented by LDL receptor (LDLR) and apolipoprotein E (ApoE) gene deletion mice, respectively. Given the impact of FH and FCH on health outcomes, we determined the impact of FH/FCH on vascular structure in LDLR and ApoE mice. LDLR, ApoE and control mice were utilized at 12-13 and 22-23 weeks when gracilis arteries were studied for wall mechanics and gastrocnemius muscles were harvested for microvessel density measurements. Conduit arteries and plasma samples were harvested for biochemical analyses. Arteries from ApoE and LDLR exhibited blunted expansion versus control, reduced distensibility and left-shifted stress versus strain relation (LDLR > ApoE). Microvessel density was reduced in ApoE and LDLR (ApoE > LDLR). Secondary analyses suggested that wall remodeling in LDLR was associated with cholesterol and MCP-1, while rarefaction in ApoE was associated with tumor necrosis factors-alpha, triglycerides and vascular production of TxA(2). Remodeling in ApoE and LDLR appears distinct; as that in LDLR is preferential for vascular walls, while that for ApoE is stronger for rarefaction. Remodeling in LDLR may be associated with cellular adhesion, while that in ApoE may be associated with pro-apoptotsis and constrictor prostanoid generation.
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Affiliation(s)
- Phoebe A Stapleton
- Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, WV 26506, USA
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26
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Jourdan T, Djaouti L, Demizieux L, Gresti J, Vergès B, Degrace P. Liver carbohydrate and lipid metabolism of insulin-deficient mice is altered by trans-10, cis-12 conjugated linoleic acid. J Nutr 2009; 139:1901-7. [PMID: 19692528 DOI: 10.3945/jn.109.111062] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Feeding mice the trans-10, cis-12 (t10c12) conjugated linoleic acid (CLA) isomer is associated with lipodystrophy, insulin resistance, hyperinsulinemia, and liver steatosis. It has been hypothesized that CLA-induced liver steatosis is the result of increased hepatic lipogenesis stimulated by high insulin levels. We studied the effects of a 12-d t10c12CLA treatment (1 g/100 g diet) on liver carbohydrate and lipid metabolism in control and streptozotocin (STZ)-injected mice. STZ mice were characterized by insulin deficiency, hypertriglyceridemia, and depletion of liver triglyceride and glycogen. Remarkably, feeding t10c12CLA to diabetic mice (STZ-CLA) normalized these variables. Reconstitution of fat stores in the livers of STZ-CLA mice was associated with lower fatty acid (FA) oxidation rates and greater malonyl-CoA concentration than in STZ mice. FA translocase and VLDL receptor mRNA levels were greater in STZ-CLA than in STZ mice, suggesting that t10c12CLA increased liver lipid uptake. Phosphoenolpyruvate carboxykinase mRNA levels and AMP kinase phosphorylation were lower in STZ-CLA than in STZ mice, indicating that t10c12CLA may reduce glucogenic activity and promote glycogenesis in diabetic mice. Because glycemia and glucokinase expression were not modified by t10c12CLA treatment, we postulated that glycogen accumulation is likely not the result of an effect of t10c12CLA on plasma glucose utilization, but rather is due to the contribution of lactate, the concentration of which was higher in muscle of STZ-CLA mice. The results demonstrate that t10c12CLA stimulates liver lipid accumulation in the absence of insulin and, thus, suggest that t10c12CLA can improve liver carbohydrate and lipid metabolism in type I diabetic mice.
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Affiliation(s)
- Tony Jourdan
- Unité Mixte de Recherche 866 INSERM-Université de Bourgogne, Equipe physiopathologie des dyslipidémies, Faculté des Sciences Gabriel, 21000 Dijon, France
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27
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Daniels TF, Killinger KM, Michal JJ, Wright RW, Jiang Z. Lipoproteins, cholesterol homeostasis and cardiac health. Int J Biol Sci 2009; 5:474-88. [PMID: 19584955 PMCID: PMC2706428 DOI: 10.7150/ijbs.5.474] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 06/19/2009] [Indexed: 12/22/2022] Open
Abstract
Cholesterol is an essential substance involved in many functions, such as maintaining cell membranes, manufacturing vitamin D on surface of the skin, producing hormones, and possibly helping cell connections in the brain. When cholesterol levels rise in the blood, they can, however, have dangerous consequences. In particular, cholesterol has generated considerable notoriety for its causative role in atherosclerosis, the leading cause of death in developed countries around the world. Homeostasis of cholesterol is centered on the metabolism of lipoproteins, which mediate transport of the lipid to and from tissues. As a synopsis of the major events and proteins that manage lipoprotein homeostasis, this review contributes to the substantial attention that has recently been directed to this area. Despite intense scrutiny, the majority of phenotypic variation in total cholesterol and related traits eludes explanation by current genetic knowledge. This is somewhat disappointing considering heritability estimates have established these traits as highly genetic. Thus, the continued search for candidate genes, mutations, and mechanisms is vital to our understanding of heart disease at the molecular level. Furthermore, as marker development continues to predict risk of vascular illness, this knowledge has the potential to revolutionize treatment of this leading human disease.
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Affiliation(s)
- Tyler F Daniels
- Department of Animal Sciences, Washington State University, Pullman, WA 99164-6351, USA
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28
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Sakai K, Tiebel O, Ljungberg MC, Sullivan M, Lee HJ, Terashima T, Li R, Kobayashi K, Lu HC, Chan L, Oka K. A neuronal VLDLR variant lacking the third complement-type repeat exhibits high capacity binding of apoE containing lipoproteins. Brain Res 2009; 1276:11-21. [PMID: 19393635 DOI: 10.1016/j.brainres.2009.04.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 03/30/2009] [Accepted: 04/12/2009] [Indexed: 12/31/2022]
Abstract
Very-low-density lipoprotein receptor (VLDLR) is a multi ligand apolipoprotein E (apoE) receptor and is involved in brain development through Reelin signaling. Different forms of VLDLR can be generated by alternative splicing. VLDLR-I contains all exons. VLDLR-II lacks an O-linked sugar domain encoded by exon 16, while VLDLR-III lacks the third complement-type repeat in the ligand binding domain encoded by exon 4. We quantitatively compared lipoprotein binding to human VLDLR variants and analyzed their mRNA expression in both human cerebellum and mouse brain. VLDLR-III exhibited the highest capacity in binding to apoE enriched beta-VLDL in vitro and was more effective in removing apoE containing lipoproteins from the circulation than other variants in vivo. In human cerebellum, the major species was VLDLR-II, while the second most abundant species was a newly identified VLDLR-IV which lacks both exon 4 and 16. VLDLR-I was present at low levels. In adult mice, exon 4 skipping varied between 30 and 47% in different brain regions, while exon 16 skipping ranged by 51-76%. Significantly higher levels of VLDLR proteins were found in mouse cerebellum and cerebral cortex than other regions. The deletions of exon 4 and exon 16 frequently occurred in primary neurons, indicating that newly identified variant VLDLR-IV is abundant in neurons. In contrast, VLDLR mRNA lacking exon 4 was not detectable in primary astrocytes. Such cell type-specific splicing patterns were found in both mouse cerebellum and cerebral cortex. These results suggest that a VLDLR variant lacking the third complement-type repeat is generated by neuron-specific alternative splicing. Such differential splicing may result in different lipid uptake in neurons and astrocytes.
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Affiliation(s)
- Keiko Sakai
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
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29
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Hofmann SM, Zhou L, Perez-Tilve D, Greer T, Grant E, Wancata L, Thomas A, Pfluger PT, Basford JE, Gilham D, Herz J, Tschöp MH, Hui DY. Adipocyte LDL receptor-related protein-1 expression modulates postprandial lipid transport and glucose homeostasis in mice. J Clin Invest 2008; 117:3271-82. [PMID: 17948131 DOI: 10.1172/jci31929] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 08/01/2007] [Indexed: 12/13/2022] Open
Abstract
Diet-induced obesity and its serious consequences such as diabetes, cardiovascular disease, and cancer are rapidly becoming a major global health threat. Therefore, understanding the cellular and molecular mechanisms by which dietary fat causes obesity and diabetes is of paramount importance in order to identify preventive and therapeutic strategies. Increased dietary fat intake results in high plasma levels of triglyceride-rich lipoproteins (TGRL). Tissue uptake of TGRL has been shown to promote glucose intolerance. We generated mice with an adipocyte-specific inactivation of the multifunctional receptor LDL receptor-related protein-1 (LRP1) to determine its role in mediating the effects of TGRL on diet-induced obesity and diabetes. Knockout mice displayed delayed postprandial lipid clearance, reduced body weight, smaller fat stores, lipid-depleted brown adipocytes, improved glucose tolerance, and elevated energy expenditure due to enhanced muscle thermogenesis. We further demonstrated that inactivation of adipocyte LRP1 resulted in resistance to dietary fat-induced obesity and glucose intolerance. These findings identify LRP1 as a critical regulator of adipocyte energy homeostasis, where functional disruption leads to reduced lipid transport, increased insulin sensitivity, and muscular energy expenditure.
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Affiliation(s)
- Susanna M Hofmann
- Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45237, USA
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30
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Jacobs F, Van Craeyveld E, Feng Y, Snoeys J, De Geest B. Adenoviral low density lipoprotein receptor attenuates progression of atherosclerosis and decreases tissue cholesterol levels in a murine model of familial hypercholesterolemia. Atherosclerosis 2008; 201:289-97. [PMID: 18378244 DOI: 10.1016/j.atherosclerosis.2008.02.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 02/05/2008] [Accepted: 02/24/2008] [Indexed: 10/22/2022]
Abstract
Familial hypercholesterolemia is an autosomal codominant disease characterized by high concentrations of pro-atherogenic lipoproteins and premature atherosclerosis secondary to low density lipoprotein receptor (LDLr) deficiency. In the current study, the effects of gene transfer with 5 x 10(10) particles of E1E3E4-deleted adenoviral vectors expressing the LDLr (AdLDLr) or VLDLr (AdVLDLr) under control of the hepatocyte-specific human alpha(1)-antitrypsin promoter and 4 copies of the human apo E enhancer in C57BL/6 LDLr(-/-) mice were investigated. Evaluation was performed in both sexes and in mice fed either standard chow or an atherogenic diet containing 0.2% cholesterol and 10% coconut oil. Compared to control mice, AdLDLr and AdVLDLr persistently decreased plasma non-HDL cholesterol in both sexes and on both diets. Six months after LDLr gene transfer in mice fed the atherogenic diet, average intimal area was 2.5-fold (p<0.01) and 3.2-fold (p<0.001) lower in male and female mice, respectively, compared to controls. In mice fed standard chow, intimal area was reduced 22-fold (p<0.001) and 21-fold (p<0.001) after LDLr gene transfer in male and female mice, respectively. We show that non-HDL lipoproteins are more atherogenic in female mice, independent of sex differences of plasma HDL cholesterol levels, and that saturated fat does not have an effect on atherosclerosis independent of plasma cholesterol levels. Finally, quantification of tissue cholesterol levels indicates that AdLDLr does not induce cholesterol accumulation in the liver and reduces cholesterol content in the myocardium, quadriceps muscle and kidney. In conclusion, hepatocyte-specific LDLr gene transfer significantly improves cholesterol homeostasis in LDLr(-/-) mice.
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Affiliation(s)
- Frank Jacobs
- Center for Molecular and Vascular Biology, University of Leuven, Campus Gasthuisberg, Leuven, Belgium
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31
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Antitumor Effects of Systemically Delivered Adenovirus Harboring Trans-Splicing Ribozyme in Intrahepatic Colon Cancer Mouse Model. Clin Cancer Res 2008; 14:281-90. [DOI: 10.1158/1078-0432.ccr-07-1524] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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32
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Hong SH, Jeong JS, Lee YJ, Jung HI, Cho KS, Kim CM, Kwon BS, Sullenger BA, Lee SW, Kim IH. In Vivo Reprogramming of hTERT by Trans-splicing Ribozyme to Target Tumor Cells. Mol Ther 2008; 16:74-80. [PMID: 17700543 DOI: 10.1038/sj.mt.6300282] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We have developed and validated a new tumor-targeting gene therapy strategy based upon the targeting and replacement of human telomerase reverse transcriptase (hTERT) RNA, using a trans-splicing ribozyme. By constructing novel adenoviral vectors harboring the hTERT-targeting trans-splicing ribozymes with the downstream reporter gene (Ad-Ribo-LacZ) or suicide gene (Ad-Ribo-HSVtk) driven by the cytomegalovirus (CMV) promoter, we demonstrated that this viral system selectively marks tumor cells expressing hTERT or sensitizes tumor cells to prodrug treatments. We confirmed that Ad-Ribo-LacZ successfully and selectively delivered a ribozyme that performed a highly specific trans-splicing reaction into hTERT-expressing cancer cells, both in vitro and in a peritoneal carcinomatosis nude mouse model. We also determined that the hTERT-specific expression of the suicide gene in the Ad-Ribo-HSVtk, and treatment with the corresponding prodrug, reduced tumor progression with almost the same efficacy as the strong constitutive CMV promoter-driven adenovirus, both in cancer cell lines and in nude mouse HT-29 xenografts. These observations provide the basis for a novel approach to cancer gene therapy, and demonstrate that trans-splicing ribozymes can be employed as targeting anti-cancer agents which recognize cancer-specific transcripts and reprogram them, thereby combating cancerous cells.
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Affiliation(s)
- Seung-Hee Hong
- Research Institute & Hospital, National Cancer Center, Goyang, South Korea
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33
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Hong SH, Jeong JS, Lee YJ, Jung HI, Kim KT, Kim YH, Lee YS, Lee SW, Bae CD, Park J, Kim IH. Molecular imaging of endogenous mRNA expression in a mouse tumor model by adenovirus harboringtrans-splicing ribozyme. FEBS Lett 2007; 581:5396-400. [DOI: 10.1016/j.febslet.2007.10.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 10/17/2007] [Accepted: 10/18/2007] [Indexed: 11/27/2022]
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Stolt PC, Bock HH. Modulation of lipoprotein receptor functions by intracellular adaptor proteins. Cell Signal 2006; 18:1560-71. [PMID: 16725309 DOI: 10.1016/j.cellsig.2006.03.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Accepted: 03/21/2006] [Indexed: 10/24/2022]
Abstract
Members of the low density lipoprotein (LDL) receptor gene family are critically involved in a wide range of physiological processes including lipid and vitamin homeostasis, cellular migration, neurodevelopment, and synaptic plasticity, to name a few. Lipoprotein receptors exert these diverse biological functions by acting as cellular uptake receptors or by inducing intracellular signaling cascades. It was discovered that a short sequence in the intracellular region of all lipoprotein receptors, Asn-Pro-X-Tyr (NPXY) is important for mediating either endocytosis or signal transduction events, and that this motif serves as a binding site for phosphotyrosine-binding (PTB) domain containing scaffold proteins. These molecular adaptors connect the transmembrane receptors with the endocytosis machinery and regulate cellular trafficking, or function as assembly sites for dynamic multi-protein signaling complexes. Whereas the LDL receptor represents the archetype of an endocytic lipoprotein receptor, the structurally closely related apolipoprotein E receptor 2 (apoER2) and very low density lipoprotein (VLDL) receptor activate a kinase-dependent intracellular signaling cascade after binding to the neuronal signaling molecule Reelin. This review focuses on two related PTB domain containing adaptor proteins that mediate these divergent lipoprotein receptor responses, ARH (autosomal recessive hypercholesterolemia protein) and Dab1 (disabled-1), and discusses the structural and molecular basis of this different behaviour.
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Affiliation(s)
- Peggy C Stolt
- Max Planck Institute for Biophysics, Max-von-Laue Str. 3, D-60438 Frankfurt/Main, Germany
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35
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Oka K, Belalcazar LM, Dieker C, Nour EA, Nuno-Gonzalez P, Paul A, Cormier S, Shin JK, Finegold M, Chan L. Sustained phenotypic correction in a mouse model of hypoalphalipoproteinemia with a helper-dependent adenovirus vector. Gene Ther 2006; 14:191-202. [PMID: 16957769 PMCID: PMC1780075 DOI: 10.1038/sj.gt.3302819] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We examined the efficacy and host response to the adenovirus (Ad)-mediated delivery of human apolipoprotein A-I (APOA1) gene to the liver of APOA1(-/-) mice. Administration of a first-generation vector (FGAd-AI) resulted in a transient appearance of APOA1 in plasma and induced an anti-APOA1 antibody titer, whereas treatment with a helper-dependent vector (HDAd-AI) resulted in sustained APOA1 expression without inducing an antibody titer. With these results, we studied the effects of FGAd vectors on APOAI expression by HDAd-AI vector. Co-treatment with an FGAd vector inhibited HDAd-AI- mediated APOA1 expression independent of transgene cassettes, but only FGAd-AI induced a humoral response. Furthermore, APOA1 mRNA levels in mice co-treated with FGAd vectors were much lower than those expected from the vector copy number, suggesting that DNA of FGAd vectors interferes with the HDAd-AI vector's APOA1 promoter. A single treatment with an HDAd-AI vector produced a supraphysiological plasma APOA1 level that gradually declined to about half the normal human level over the course of 2 years, associated with a plasma cholesterol level that is persistently higher than that in controls. This investigation provides the proof of principle that liver-directed HDAd gene delivery is effective for the long-term phenotypic correction of monogenic hypoalphalipoproteinemia.
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Affiliation(s)
- K Oka
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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36
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Corbin IR, Li H, Chen J, Lund-Katz S, Zhou R, Glickson JD, Zheng G. Low-density lipoprotein nanoparticles as magnetic resonance imaging contrast agents. Neoplasia 2006; 8:488-98. [PMID: 16820095 PMCID: PMC1601463 DOI: 10.1593/neo.05835] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Low-density lipoproteins (LDLs) are a naturally occurring endogenous nanoplatform in mammalian systems. These nanoparticles (22 nm) specifically transport cholesterol to cells expressing the LDL receptor (LDLR). Several tumors overexpress LDLRs presumably to provide cholesterol to sustain a high rate of membrane synthesis. Amphiphilic gadolinium (Gd)-diethylenetriaminepentaacetic acid chelates have been incorporated into the LDL to produce a novel LDLR-targeted magnetic resonance imaging (MRI) contrast agent. The number of Gd chelates per LDL particle ranged between 150 and 496 Gd(III). In vitro studies demonstrated that Gd-labeled LDL retained a similar diameter and surface charge as the native LDL particle. In addition, Gd-labeled LDL retained selective cellular binding and uptake through LDLR-mediated endocytosis. Finally, Gd-labeled LDLs exhibited significant contrast enhancement 24 hours after administration in nude mice with human hepatoblastoma G2 xenografts. Thus, Gd-labeled LDL demonstrates potential use as a targeted MRI contrast agent for in vivo tumor detection.
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Affiliation(s)
- Ian R Corbin
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hui Li
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Juan Chen
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sissel Lund-Katz
- Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Rong Zhou
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jerry D Glickson
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gang Zheng
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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37
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Li Z, Qiao H, Lebherz C, Choi SR, Zhou X, Gao G, Kung HF, Rader DJ, Wilson JM, Glickson JD, Zhou R. Creatine kinase, a magnetic resonance-detectable marker gene for quantification of liver-directed gene transfer. Hum Gene Ther 2006; 16:1429-38. [PMID: 16390274 DOI: 10.1089/hum.2005.16.1429] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We reported previously the in vivo detection of ectopic and transient expression of creatine kinase gene (ck) in the liver by phosphorus-31 magnetic resonance spectroscopy ((31)P MRS). Here we demonstrate the feasibility of using ck as a reporter gene to monitor the transfer of low-density lipoprotein receptor (LDLr) gene to LDLr(/) mice, a preclinical model for familial hypercholesterolemia. A recombinant adenovirus was generated that carries the creatine kinase gene (ck) and human LDL receptor gene (hLDLr) linked by an internal ribosomal entry site sequence. Intravenous injection of the adenovirus into LDLr(/)mice (1 x 10(11) viral particles/mouse) resulted in transduction of more than 90% of hepatocytes in the liver. Simultaneous expression of ck and LDLr was confirmed by Western analysis of the transduced livers. Through precise regulation of transgene expression in hepatocytes in vitro, an excellent correlation (R(2) = 0.96) between LDLr and ck expression was demonstrated over a wide range of viral dose. In vivo 31P MRS was employed to detect the metabolic product (i.e., phosphocreatine) of the creatine kinase protein (CK) reaction. CK activity, which is a true measure of ck gene expression, was quantified in vivo by magnetization transfer. Because ck is expressed abundantly in human muscle and brain but is absent from the liver, ck is useful to monitor any liver directed gene transfer. Use of the ck reporter would facilitate the clinical translation of gene therapy by providing a nondestructive readout of the level and duration of therapeutic gene expression.
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Affiliation(s)
- Zijun Li
- Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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38
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Kim KU, Seo SY, Heo KY, Yoo YH, Kim HJ, Lee HS, Choi SS, Hwang TH, Lee HJ. Antitumor activity of TRAIL recombinant adenovirus in human malignant glioma cells. J Korean Med Sci 2005; 20:1046-52. [PMID: 16361820 PMCID: PMC2779307 DOI: 10.3346/jkms.2005.20.6.1046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Tumor necrosis factor-Related Apoptosis-Inducing Ligand (TRAIL) has been reported to specifically kill malignant cells but to be relatively nontoxic to normal cells. One of disadvantages to previous in vivo protocols was the need for large quantities of TRAIL recombinant protein to suppress tumor growth. To evaluate the antitumor activity and therapeutic value of the TRAIL gene, we constructed adenoviral vectors expressing the human TRAIL gene (Ad.hTRAIL) and transferred them into malignant glioma cells in vitro and tumors in vivo, as an alternative to recombinant soluble TRAIL protein. The results show that TRAIL-sensitive glioma cells infected Ad.hTRAIL undergo apoptosis through the production and expression of TRAIL protein. The in vitro transfer elicited apoptosis, as demonstrated by the quantification of viable or apoptotic cells and by the analysis of cleavage of poly (ADP-ribose) polymerase. Furthermore, in vivo administration of Ad.hTRAIL at the site of tumor implantation suppressed the outgrowth of human glioma xenografts in SCID mice. These results further define Ad.hTRAIL as an anti-tumor therapeutic and demonstrate its potential use as an alternative approach to treatment for malignant glioma.
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Affiliation(s)
- Ki-Uk Kim
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
| | - Su-Yeong Seo
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
| | - Ki-Young Heo
- Department of Pathology, Pusan National University College of Medicine, Busan, Korea
| | - Young-Hyun Yoo
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
| | - Hye-Jin Kim
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
| | - Hyeong-Sik Lee
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
| | - Sun-Seob Choi
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
| | - Tae-Ho Hwang
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
| | - Hye-Jeong Lee
- Brain Tumor Research, Dong-A University College of Medicine, Busan, Korea
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39
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Li Z, Qiao H, Lebherz C, Choi SR, Zhou X, Gao G, Kung HF, Rader DJ, Wilson JM, Glickson JD, Zhou R. Creatine Kinase, a Magnetic Resonance-Detectable Marker Gene for Quantification of Liver-Directed Gene Transfer. Hum Gene Ther 2005. [DOI: 10.1089/hum.2005.16.ft-140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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40
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Gauster M, Hrzenjak A, Schick K, Frank S. Endothelial lipase is inactivated upon cleavage by the members of the proprotein convertase family. J Lipid Res 2005; 46:977-87. [PMID: 15722560 DOI: 10.1194/jlr.m400500-jlr200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mature endothelial lipase (EL) is a 68 kDa glycoprotein. In HepG2 cells infected with adenovirus encoding human EL, the mature EL was detectable in the cell lysates and heparin-releasable fractions. In contrast, cell media of these cells contained two EL fragments: an N-terminal 40 kDa fragment and a C-terminal 28 kDa fragment. N-terminal protein sequencing of the His-tagged 28 kDa fragment revealed that EL is cleaved on the C terminus of the sequence RNKR330, the consensus cleavage sequence for mammalian proprotein convertases (pPCs). Replacement of Arg-330 with Ser by site-directed mutagenesis totally abolished EL processing. EL processing could efficiently be attenuated by specific inhibitors of pPCs, alpha1-antitrypsin Portland (alpha1-PDX) and alpha1-antitrypsin variant AVRR. Coexpression of the pPCs furin, PC6A, and PACE4 with EL resulted in a complete conversion of the full-length EL to a truncated 40 kDa fragment. Exogenously added EL was also processed by cells, and the processing could be attenuated by alpha1-PDX. The expressed N-terminal 40 kDa fragment of EL (EL-40) harboring the catalytic site failed to hydrolyze [14C]NEFA from [14C]dipalmitoyl-PC-labeled HDL. EL-40 was incapable of bridging 125I-labeled HDL to the cells and had no impact on plasma lipid concentration when overexpressed in mice. Thus, our results demonstrate that pPCs are involved in the inactivation process of EL.
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Affiliation(s)
- Martin Gauster
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University, Graz A-8010, Austria
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41
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Abstract
One of the prerequisites for the successful application of gene vaccination and therapy is the development of efficient gene delivery vectors. The rate-limiting nature of vectors was clearly manifested during the first wave of gene therapy testing, resulting in the demand for more effective and suitable vector systems. Adenoviral (Ad) vectors have recently played a central role in the development of gene-vector technology due to their practical advantages and potential applications. A large number of preclinical and clinical studies both have generated an overwhelming amount of data and literature on this vector system. It is the intention of this article to provide a systematic and broad spectrum review of this system, outlining the principle, potential, and limitations, and evaluating the rational development of this delivery approach. Recombinant adenoviruses (Ad), helper cell lines, and related technologies have been developed and applied to many indications owing to progress in virological research, molecular and cellular biology, eukaryotic protein expression, recombinant vaccines, and gene therapy. The technical depth this article covers should be useful to both the experienced researcher and to beginners in this field.
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Affiliation(s)
- W W Zhang
- Gene Therapy Unit, Baxter Healthcare Corporation, Route 120 & Wilson Road, WG2-3S, Round Lake, IL 60073-0490, USA
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42
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Sato N, Kobayashi K, Inoguchi T, Sonoda N, Imamura M, Sekiguchi N, Nakashima N, Nawata H. Adenovirus-mediated high expression of resistin causes dyslipidemia in mice. Endocrinology 2005; 146:273-9. [PMID: 15471967 DOI: 10.1210/en.2004-0985] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The adipocyte-derived hormone resistin has been proposed as a possible link between obesity and insulin resistance in murine models. Many recent studies have reported physiological roles for resistin in glucose homeostasis, one of which is enhancement of glucose production from the liver by up-regulating gluconeogenic enzymes such as glucose-6-phosphatase and phosphoenolpyruvate carboxykinase. However, its in vivo roles in lipid metabolism still remain to be clarified. In this study, we investigated the effects of resistin overexpression on insulin action and lipid metabolism in C57BL/6 mice using an adenoviral gene transfer technique. Elevated plasma resistin levels in mice treated with the resistin adenovirus (AdmRes) were confirmed by Western blotting analysis and RIAs. Fasting plasma glucose levels did not differ between AdmRes-treated mice and controls, but the basal insulin concentration was significantly elevated in AdmRes-treated mice. In AdmRes-treated mice, the glucose-lowering effect of insulin was impaired, as evaluated by insulin tolerance tests. Furthermore, total cholesterol and triglyceride concentrations were significantly higher, whereas the high-density lipoprotein cholesterol level was significantly lower. Lipoprotein analysis revealed that low-density lipoprotein was markedly increased in AdmRes-treated mice, compared with controls. In addition, in vivo Triton WR-1339 studies showed evidence of enhanced very low-density lipoprotein production in AdmRes-treated mice. The expressions of genes involved in lipoprotein metabolism, such as low-density lipoprotein receptor and apolipoprotein AI in the liver, were decreased. These results suggest that resistin overexpression induces dyslipidemia in mice, which is commonly seen in the insulin-resistant state, partially through enhanced secretion of lipoproteins.
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Affiliation(s)
- Naoichi Sato
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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43
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Li H, Gray BD, Corbin I, Lebherz C, Choi H, Lund-Katz S, Wilson JM, Glickson JD, Zhou R. MR and fluorescent imaging of low-density lipoprotein receptors. Acad Radiol 2004; 11:1251-9. [PMID: 15561572 DOI: 10.1016/j.acra.2004.08.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 07/22/2004] [Accepted: 08/12/2004] [Indexed: 01/08/2023]
Abstract
RATIONALE AND OBJECTIVES Over-expression of low-density lipoprotein receptors (LDLRs) occurs in many types of malignancies and is related to the requirement for lipids for rapid proliferation of the tumors. On the other hand, LDLRs that are unable to bind LDL are found on hepatocytes of patients with familial hypercholesterolemia (FH), a genetic disease that leads to premature atherosclerosis and death. The highly selective binding of LDL to LDLR makes these particles ideal carriers of therapeutic and diagnostic contrast agents into the targeted cells. The objectives of this paper are to examine whether a prototype contrast agent (PTIR267) with dual detection properties is suitable for labeling of LDL particles for in vivo detection of LDLR by magnetic resonance imaging (MRI) and for in vitro monitoring of cellular localization by confocal fluorescence microscopy. MATERIALS AND METHODS PTIR267 is a lipophilic GdDTPA derivative conjugated to a fluorescent dye. The conjugated dye molecule makes the probe sufficiently water soluble to allow labeling of LDL by a brief incubation of LDL with PTIR267 dissolved in PBS at 37 degrees C (mole ratio LDL: PTIR267 = 0.09:1). The molar relaxivity of PTIR267 in saline is 26 mM(-1)s(-1). Specific LDLR-mediated uptake of PTIR267-labeled LDL was demonstrated in vitro by confocal fluorescence imaging of B16 melanoma cells using confocal fluorescence imaging. In vivo uptake of PTIR267-labeled LDL by a subcutaneously implanted B16 melanoma in mice leads to 30% decrease in longitudinal relaxation time (T(1)) in the tumor. In vivo uptake of PTIR267-labeled LDL leads to 70% decrease in T(1) in a normal C57BL/6 mouse liver; however, in the liver of LDL receptor gene knockout (LDLr-/-) mice with C57BL/6 background, only 12% decrease in T(1) is observed. CONCLUSIONS The dual fluorescence and MR imaging properties of PTIR267, combined with the ease of LDL labeling, suggest that it will be a useful tool for optimization of LDLR-targeted cancer diagnosis or therapy and for monitoring the efficacy of gene therapy of FH.
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Affiliation(s)
- Hui Li
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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44
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Bovenschen N, van Dijk KW, Havekes LM, Mertens K, van Vlijmen BJM. Clearance of coagulation factor VIII in very low-density lipoprotein receptor knockout mice. Br J Haematol 2004; 126:722-5. [PMID: 15327526 DOI: 10.1111/j.1365-2141.2004.05093.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Low-density lipoprotein receptor-related protein (LRP) contributes to factor VIII (FVIII) catabolism in vivo. Besides LRP, FVIII also interacts with very low-density lipoprotein receptor (VLDLR) in vitro. We investigated the physiological role of VLDLR in FVIII catabolism, using knockout mouse models for VLDLR and LRP, alone and in combination. VLDLR(-/-) mice displayed normal plasma FVIII, whereas VLDLR(-/-) LRP(-) double-knockout mice had slightly increased FVIII compared with LRP-deficient mice. Remarkably, VLDLR deficiency slightly accelerated FVIII clearance. Adenovirus-mediated overexpression of VLDLR did not lower plasma FVIII in LRP-deficient mice. We conclude that VLDLR does not act in concert with LRP in FVIII clearance in vivo.
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Affiliation(s)
- Niels Bovenschen
- Department of Plasma Proteins, Sanquin Research at CLB, Plesmanlaan 125, 1066 CX Amsterdam, the Netherlands
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45
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Nomura S, Merched A, Nour E, Dieker C, Oka K, Chan L. Low-density lipoprotein receptor gene therapy using helper-dependent adenovirus produces long-term protection against atherosclerosis in a mouse model of familial hypercholesterolemia. Gene Ther 2004; 11:1540-8. [PMID: 15269711 DOI: 10.1038/sj.gt.3302310] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We tested the efficacy of low-density lipoprotein receptor (LDLR) therapy using helper-dependent adenovirus (HD-Ad), comparing it with that of very low-density lipoprotein receptor (VLDLR), an LDLR homolog. We treated high cholesterol diet fed LDLR-/- mice with a single intravenous injection of HD-Ad expressing monkey LDLR (1.5 x 10(13) or 5 x 10(12) VP/kg) or VLDLR. Throughout the 24-week experiment, plasma cholesterol of LDLR-treated mice was lower than that of VLDLR-treated mice, which was in turn lower than that of PBS-treated mice. Anti-LDLR antibodies developed in 2/10 mice treated with high-dose HD-Ad-LDLR but in none (0/14) of the other treatment groups. HD-Ad-treated mice displayed significant retardation of atherosclerotic lesion progression. We next tested the long-term efficacy of low-dose HD-Ad-LDLR injected into 12-week-old LDLR-/- mice. After 60 weeks, atherosclerosis lesions covered approximately 50% of the surface of aortas of control mice, whereas aortas of treated mice were essentially lesion-free. The lipid lowering effect of HD-Ad-LDLR lasted at least 108 weeks (>2 years) when all control mice had died. In addition to retarding lesion progression, treatment caused lesion remodeling from a vulnerable-looking to a more stable-appearing phenotype. In conclusion, HD-Ad-mediated LDLR gene therapy is effective in conferring long-term protection against atherosclerosis in a mouse model of familial hypercholesterolemia.
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Affiliation(s)
- S Nomura
- Department of Molecular and Cellular Biology, Baylor College of Medicine, TX 77030, USA
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46
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Pastore L, Belalcazar LM, Oka K, Cela R, Lee B, Chan L, Beaudet AL. Helper-dependent adenoviral vector-mediated long-term expression of human apolipoprotein A-I reduces atherosclerosis in apo E-deficient mice. Gene 2004; 327:153-60. [PMID: 14980712 DOI: 10.1016/j.gene.2003.11.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2003] [Revised: 09/30/2003] [Accepted: 11/14/2003] [Indexed: 10/26/2022]
Abstract
Apolipoprotein A-I (APOA-I) is the major protein component of high-density lipoproteins (HDL). It has been shown that over-expression of human APOA-I increases HDL cholesterol and decreases atherosclerosis. We constructed a helper-dependent adenoviral (HD-Ad) vector that contains the entire human APOA-I gene (hgAI). Intravenous delivery of 1x10(13) viral particles/kg of this vector was followed by high levels of human APOA-I expression (up to 200 mg/dl) in the absence of detectable hepatic toxicity. We treated apo E-deficient mice with the hgAI vector and fed them either with a high-fat diet or with regular chow. As a control, two groups of mice were treated with PBS. The apo E-deficient mice treated with the hgAI vector showed supraphysiological levels of expression of human APOA-I at week 4 and high levels of HDL cholesterol compared to the control groups. Analysis of aortic atherosclerotic lesions 20 weeks after treatment, showed a significant reduction of lesion size in the treated mice with both diets. In conclusion, liver-directed gene transfer of human APOA-I using a HD-Ad vector resulted in a reduction of the development of atherosclerosis with the absence of significant toxicity.
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Affiliation(s)
- Lucio Pastore
- Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA.
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Martins IJ, Redgrave TG. Obesity and post-prandial lipid metabolism. Feast or famine? J Nutr Biochem 2004; 15:130-41. [PMID: 15023394 DOI: 10.1016/j.jnutbio.2003.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2003] [Revised: 10/15/2003] [Accepted: 10/21/2003] [Indexed: 10/26/2022]
Abstract
Both in Western countries and in third world countries there is an increasing incidence of obesity. Obesity per se or insulin resistance associated with obesity may increase cardiovascular risk factors including dyslipidemia, hypertension and Type 2 diabetes. Over the past decade the understanding has increased of specific mediators in the hypothalamus that are involved in regulating food intake and body weight. In obese humans fasting plasma lipids can be normal but postprandial lipid metabolism is abnormal with an accumulation of triglyceride-rich remnant lipoproteins. In viscerally obese men chylomicron remnant catabolism was markedly decreased when compared with lean individuals. The decreased clearance of chylomicron remnants in viscerally obese subjects may be explained by competition between chylomicron remnants and the increased hepatic production of VLDL for clearance by low density lipoprotein receptors. Increased food intake in rodent models of obesity was shown to be associated with a delay in the catabolism of remnant lipoprotein particles. Prevention of hyperphagia was found to correct the impairment in the metabolism of remnant lipoproteins. Under fasting and food restricted conditions the improvement of remnant metabolism was associated with an increased oxidation of remnant lipids as determined by a novel stable isotope breath test. Anti-obesity and lipid lowering drugs have been used for the treatment of obesity. Inhibitors of cholesterol synthesis inhibitors (statins) have been shown to be effective in treating dyslipidemia. Inhibition of cholesterol synthesis with Atorvastatin was shown to improve chylomicron metabolism by increasing chylomicron remnant catabolism in obese subjects as assessed by the newly developed stable isotope breath test.
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Affiliation(s)
- Ian J Martins
- Centre for Human Genetics, Edith Cowan University, Joondalup Drive, Joondalup, Perth 6027, Australia.
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48
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Takahashi S, Sakai J, Fujino T, Hattori H, Zenimaru Y, Suzuki J, Miyamori I, Yamamoto TT. The Very Low-density Lipoprotein (VLDL) Receptor: Characterization and Functions as a Peripheral Lipoprotein Receptor. J Atheroscler Thromb 2004; 11:200-8. [PMID: 15356379 DOI: 10.5551/jat.11.200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The very low-density lipoprotein (VLDL) receptor is a member of the low-density lipoprotein (LDL) receptor family. In vitro and in vivo studies have shown that VLDL receptor binds triglyceride (TG)-rich lipoproteins but not LDL, and functions as a peripheral remnant lipoprotein receptor. VLDL receptor is expressed abundantly in fatty acid-active tissues (heart, skeletal muscle and fat), the brain and macrophages. It is likely that VLDL receptor functions in concert with lipoprotein lipase (LPL), which hydrolyses TG in VLDL and chylomicron. In contrast to the LDL receptor, VLDL receptor binds apolipoprotein (apo) E2/2 VLDL particles as well as apoE3/3 VLDL, and the expression is not down-regulated by intracellular lipoproteins. Recently, various functions of the VLDL receptor have been reported in lipoprotein metabolism, metabolic syndrome/atherosclerosis, cardiac fatty acid metabolism, neuronal migration and angiogenesis/tumor growth. Gene therapy of VLDL receptor into the liver showed a benefit effect for lipoprotein metabolism in both LDL receptor knockout and apoE mutant mice. Beyond its function as a peripheral lipoprotein receptor, possibilities of its physiological function have been extended to include signal transduction, angiogenesis and tumor growth.
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Affiliation(s)
- Sadao Takahashi
- The Third Department of Internal Medicine, University of Fukui, 23-3, Matsuokacho, Fukui, 910-1193, Japan.
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Lee M, Hwang JT, Lee HJ, Jung SN, Kang I, Chi SG, Kim SS, Ha J. AMP-activated protein kinase activity is critical for hypoxia-inducible factor-1 transcriptional activity and its target gene expression under hypoxic conditions in DU145 cells. J Biol Chem 2003; 278:39653-61. [PMID: 12900407 DOI: 10.1074/jbc.m306104200] [Citation(s) in RCA: 209] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
AMP-activated protein kinase (AMPK) functions as an energy sensor to provide metabolic adaptations under the ATP-deprived conditions such as hypoxia. In the present study, we considered a role of AMPK in the adaptive response to hypoxia by examining whether AMPK is involved in the regulation of hypoxia-inducible factor-1 (HIF-1), a heterodimeric transcription factor that is critical for hypoxic induction of physiologically important genes. We demonstrate that hypoxia or CoCl2 rapidly activated AMPK in DU145 human prostate cancer cells, and its activation preceded the induction of HIF-1 alpha expression. Under these conditions, blockade of AMPK activity by a pharmacological or molecular approach significantly attenuated hypoxia-induced responses such as HIF-1 target gene expression, secretion of vascular endothelial growth factor, glucose uptake, and HIF-1-dependent reporter gene expression, indicating that AMPK is critical for the HIF-1 transcriptional activity and its target gene expression. Its functional requirement for HIF-1 activity was also demonstrated in several different cancer cell lines, but AMPK activation alone was not sufficient to stimulate the HIF-1 transcriptional activity. We further present data showing that AMPK transmits a positive signal for HIF-1 activity via a signaling pathway that is independent of phosphatidylinositol 3-kinase/AKT and several mitogen-activated protein kinases. Taken together, our results suggest that AMPK is a novel and critical component of HIF-1 regulation, implying its new roles in oxygen-regulated cellular phenomena.
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Affiliation(s)
- Minyoung Lee
- Department of Molecular Biology, Medical Research Center for Bioreaction to Reactive Oxygen Species, Kyung Hee University College of Medicine, Seoul, Korea
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Van Hoof D, Rodenburg KW, van der Horst DJ. Lipophorin receptor-mediated lipoprotein endocytosis in insect fat body cells. J Lipid Res 2003; 44:1431-40. [PMID: 12754276 DOI: 10.1194/jlr.m300022-jlr200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
High-density lipophorin (HDLp) in the circulation of insects is able to selectively deliver lipids to target tissues in a nonendocytic manner. In Locusta migratoria, a member of the LDL receptor family has been identified and shown to mediate endocytosis of HDLp in mammalian cells transfected with the cDNA of this receptor. This insect lipophorin receptor (iLR) is temporally expressed in fat body tissue of young adult as well as larval locusts, as shown by Western blot analysis. Fluorescence microscopy revealed that fat body cells internalize fluorescently labeled HDLp and human receptor-associated protein only when iLR is expressed. Expression of iLR is down-regulated on Day 4 after an ecdysis. Consequently, HDLp is no longer internalized. By starving adult locusts immediately after ecdysis, we were able to prolong iLR expression. In addition, expression of the receptor was induced by starving adults after down-regulation of iLR. These results suggest that iLR mediates endocytosis of HDLp in fat body cells, and that expression of iLR is regulated by the demand of fat body tissue for lipids.
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Affiliation(s)
- Dennis Van Hoof
- Department of Biochemical Physiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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