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Shang R, Lee CS, Wang H, Dyer R, Noll C, Carpentier A, Sultan I, Alitalo K, Boushel R, Hussein B, Rodrigues B. Reduction in Insulin Uncovers a Novel Effect of VEGFB on Cardiac Substrate Utilization. Arterioscler Thromb Vasc Biol 2024; 44:177-191. [PMID: 38150518 DOI: 10.1161/atvbaha.123.319972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/06/2023] [Indexed: 12/29/2023]
Abstract
BACKGROUND The heart relies heavily on external fatty acid (FA) for energy production. VEGFB (vascular endothelial growth factor B) has been shown to promote endothelial FA uptake by upregulating FA transporters. However, its impact on LPL (lipoprotein lipase)-mediated lipolysis of lipoproteins, a major source of FA for cardiac use, is unknown. METHODS VEGFB transgenic (Tg) rats were generated by using the α-myosin heavy chain promoter to drive cardiomyocyte-specific overexpression. To measure coronary LPL activity, Langendorff hearts were perfused with heparin. In vivo positron emission tomography imaging with [18F]-triglyceride-fluoro-6-thia-heptadecanoic acid and [11C]-palmitate was used to determine cardiac FA uptake. Mitochondrial FA oxidation was evaluated by high-resolution respirometry. Streptozotocin was used to induce diabetes, and cardiac function was monitored using echocardiography. RESULTS In Tg hearts, the vectorial transfer of LPL to the vascular lumen is obstructed, resulting in LPL buildup within cardiomyocytes, an effect likely due to coronary vascular development with its associated augmentation of insulin action. With insulin insufficiency following fasting, VEGFB acted unimpeded to facilitate LPL movement and increase its activity at the coronary lumen. In vivo PET imaging following fasting confirmed that VEGFB induced a greater FA uptake to the heart from circulating lipoproteins as compared with plasma-free FAs. As this was associated with augmented mitochondrial oxidation, lipid accumulation in the heart was prevented. We further examined whether this property of VEGFB on cardiac metabolism could be useful following diabetes and its associated cardiac dysfunction, with attendant loss of metabolic flexibility. In Tg hearts, diabetes inhibited myocyte VEGFB gene expression and protein secretion together with its downstream receptor signaling, effects that could explain its lack of cardioprotection. CONCLUSIONS Our study highlights the novel role of VEGFB in LPL-derived FA supply and utilization. In diabetes, loss of VEGFB action may contribute toward metabolic inflexibility, lipotoxicity, and development of diabetic cardiomyopathy.
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Affiliation(s)
- Rui Shang
- Faculty of Pharmaceutical Sciences (R.S., C.S.L., H.W., B.H., B.R.), University of British Columbia, Vancouver
| | - Chae Syng Lee
- Faculty of Pharmaceutical Sciences (R.S., C.S.L., H.W., B.H., B.R.), University of British Columbia, Vancouver
| | - Hualin Wang
- Faculty of Pharmaceutical Sciences (R.S., C.S.L., H.W., B.H., B.R.), University of British Columbia, Vancouver
| | - Roger Dyer
- Department of Pediatrics (R.D.), University of British Columbia, Vancouver
| | - Christophe Noll
- Department of Medicine, Université de Sherbrooke, QC, Canada (C.N., A.C.)
| | - André Carpentier
- Department of Medicine, Université de Sherbrooke, QC, Canada (C.N., A.C.)
| | - Ibrahim Sultan
- Wihuri Research Institute and Translational Cancer Medicine Program, Biomedicum Helsinki, University of Helsinki, Finland (I.S., K.A.)
| | - Kari Alitalo
- Wihuri Research Institute and Translational Cancer Medicine Program, Biomedicum Helsinki, University of Helsinki, Finland (I.S., K.A.)
| | - Robert Boushel
- School of Kinesiology (R.B.), University of British Columbia, Vancouver
| | - Bahira Hussein
- Faculty of Pharmaceutical Sciences (R.S., C.S.L., H.W., B.H., B.R.), University of British Columbia, Vancouver
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences (R.S., C.S.L., H.W., B.H., B.R.), University of British Columbia, Vancouver
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Song W, Beigneux AP, Weston TA, Chen K, Yang Y, Nguyen LP, Guagliardo P, Jung H, Tran AP, Tu Y, Tran C, Birrane G, Miyashita K, Nakajima K, Murakami M, Tontonoz P, Jiang H, Ploug M, Fong LG, Young SG. The lipoprotein lipase that is shuttled into capillaries by GPIHBP1 enters the glycocalyx where it mediates lipoprotein processing. Proc Natl Acad Sci U S A 2023; 120:e2313825120. [PMID: 37871217 PMCID: PMC10623010 DOI: 10.1073/pnas.2313825120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/19/2023] [Indexed: 10/25/2023] Open
Abstract
Lipoprotein lipase (LPL), the enzyme that carries out the lipolytic processing of triglyceride-rich lipoproteins (TRLs), is synthesized by adipocytes and myocytes and secreted into the interstitial spaces. The LPL is then bound by GPIHBP1, a GPI-anchored protein of endothelial cells (ECs), and transported across ECs to the capillary lumen. The assumption has been that the LPL that is moved into capillaries remains attached to GPIHBP1 and that GPIHBP1 serves as a platform for TRL processing. In the current studies, we examined the validity of that assumption. We found that an LPL-specific monoclonal antibody (mAb), 88B8, which lacks the ability to detect GPIHBP1-bound LPL, binds avidly to LPL within capillaries. We further demonstrated, by confocal microscopy, immunogold electron microscopy, and nanoscale secondary ion mass spectrometry analyses, that the LPL detected by mAb 88B8 is located within the EC glycocalyx, distant from the GPIHBP1 on the EC plasma membrane. The LPL within the glycocalyx mediates the margination of TRLs along capillaries and is active in TRL processing, resulting in the delivery of lipoprotein-derived lipids to immediately adjacent parenchymal cells. Thus, the LPL that GPIHBP1 transports into capillaries can detach and move into the EC glycocalyx, where it functions in the intravascular processing of TRLs.
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Affiliation(s)
- Wenxin Song
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Anne P. Beigneux
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Thomas A. Weston
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Kai Chen
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
- School of Molecular Sciences, The University of Western Australia, Perth6009, Australia
| | - Ye Yang
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Le Phuong Nguyen
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Paul Guagliardo
- Centre for Microscopy Characterisation and Analysis, The University of Western Australia, Perth6009, Australia
| | - Hyesoo Jung
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Anh P. Tran
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Yiping Tu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Caitlyn Tran
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Gabriel Birrane
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Boston, MA02215
| | - Kazuya Miyashita
- Department of Clinical Laboratory Medicine, Gunma University School of Medicine, Maebashi371-8511, Japan
| | - Katsuyuki Nakajima
- Department of Clinical Laboratory Medicine, Gunma University School of Medicine, Maebashi371-8511, Japan
| | - Masami Murakami
- Department of Clinical Laboratory Medicine, Gunma University School of Medicine, Maebashi371-8511, Japan
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA90095
| | - Haibo Jiang
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Michael Ploug
- Finsen Laboratory, Copenhagen University Hospital-Rigshospitalet, Copenhagen NDK–2200, Denmark
- Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen NDK-2200, Denmark
| | - Loren G. Fong
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Stephen G. Young
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA90095
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3
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Kuo HCN, LaRussa Z, Xu FM, West K, Consitt L, Davidson WS, Liu M, Coschigano KT, Shi H, Lo CC. Apolipoprotein A4 Elevates Sympathetic Activity and Thermogenesis in Male Mice. Nutrients 2023; 15:2486. [PMID: 37299447 PMCID: PMC10255745 DOI: 10.3390/nu15112486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/22/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Long-chain fatty acids induce apolipoprotein A4 (APOA4) production in the small intestine and activate brown adipose tissue (BAT) thermogenesis. The increase in BAT thermogenesis enhances triglyceride clearance and insulin sensitivity. Acute administration of recombinant APOA4 protein elevates BAT thermogenesis in chow-fed mice. However, the physiological role of continuous infusion of recombinant APOA4 protein in regulating sympathetic activity, thermogenesis, and lipid and glucose metabolism in low-fat-diet (LFD)-fed mice remained elusive. The hypothesis of this study was that continuous infusion of mouse APOA4 protein would increase sympathetic activity and thermogenesis in BAT and subcutaneous inguinal white adipose tissue (IWAT), attenuate plasma lipid levels, and improve glucose tolerance. To test this hypothesis, sympathetic activity, BAT temperature, energy expenditure, body weight, fat mass, caloric intake, glucose tolerance, and levels of BAT and IWAT thermogenic and lipolytic proteins, plasma lipids, and markers of fatty acid oxidation in the liver in mice with APOA4 or saline treatment were measured. Plasma APOA4 levels were elevated, BAT temperature and thermogenesis were upregulated, and plasma triglyceride (TG) levels were reduced, while body weight, fat mass, caloric intake, energy expenditure, and plasma cholesterol and leptin levels were comparable between APOA4- and saline-treated mice. Additionally, APOA4 infusion stimulated sympathetic activity in BAT and liver but not in IWAT. APOA4-treated mice had greater fatty acid oxidation but less TG content in the liver than saline-treated mice had. Plasma insulin in APOA4-treated mice was lower than that in saline-treated mice after a glucose challenge. In conclusion, continuous infusion of mouse APOA4 protein stimulated sympathetic activity in BAT and the liver, elevated BAT thermogenesis and hepatic fatty acid oxidation, and consequently attenuated levels of plasma and hepatic TG and plasma insulin without altering caloric intake, body weight gain and fat mass.
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Affiliation(s)
- Hsuan-Chih N. Kuo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Zachary LaRussa
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Flora Mengyang Xu
- Department of Biology, Miami University, Oxford, OH 45056, USA; (F.M.X.); (H.S.)
| | - Kathryn West
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
| | - Leslie Consitt
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
| | - William Sean Davidson
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA; (W.S.D.); (M.L.)
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA; (W.S.D.); (M.L.)
| | - Karen T. Coschigano
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
| | - Haifei Shi
- Department of Biology, Miami University, Oxford, OH 45056, USA; (F.M.X.); (H.S.)
| | - Chunmin C. Lo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
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4
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LaRussa Z, Kuo HCN, West K, Shen Z, Wisniewski K, Tso P, Coschigano KT, Lo CC. Increased BAT Thermogenesis in Male Mouse Apolipoprotein A4 Transgenic Mice. Int J Mol Sci 2023; 24:4231. [PMID: 36835642 PMCID: PMC9959433 DOI: 10.3390/ijms24044231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 02/23/2023] Open
Abstract
Dietary lipids induce apolipoprotein A4 (APOA4) production and brown adipose tissue (BAT) thermogenesis. Administration of exogenous APOA4 elevates BAT thermogenesis in chow-fed mice, but not high-fat diet (HFD)-fed mice. Chronic feeding of HFD attenuates plasma APOA4 production and BAT thermogenesis in wildtype (WT) mice. In light of these observations, we sought to determine whether steady production of APOA4 could keep BAT thermogenesis elevated, even in the presence of HFD consumption, with an aim toward eventual reduction of body weight, fat mass and plasma lipid levels. Transgenic mice with overexpression of mouse APOA4 in the small intestine (APOA4-Tg mice) produce greater plasma APOA4 than their WT controls, even when fed an atherogenic diet. Thus, we used these mice to investigate the correlation of levels of APOA4 and BAT thermogenesis during HFD consumption. The hypothesis of this study was that overexpression of mouse APOA4 in the small intestine and increased plasma APOA4 production would increase BAT thermogenesis and consequently reduce fat mass and plasma lipids of HFD-fed obese mice. To test this hypothesis, BAT thermogenic proteins, body weight, fat mass, caloric intake, and plasma lipids in male APOA4-Tg mice and WT mice fed either a chow diet or a HFD were measured. When fed a chow diet, APOA4 levels were elevated, plasma triglyceride (TG) levels were reduced, and BAT levels of UCP1 trended upward, while body weight, fat mass, caloric intake, and plasma lipids were comparable between APOA4-Tg and WT mice. After a four-week feeding of HFD, APOA4-Tg mice maintained elevated plasma APOA4 and reduced plasma TG, but UCP1 levels in BAT were significantly elevated in comparison to WT controls; body weight, fat mass and caloric intake were still comparable. After 10-week consumption of HFD, however, while APOA4-Tg mice still exhibited increased plasma APOA4, UCP1 levels and reduced TG levels, a reduction in body weight, fat mass and levels of plasma lipids and leptin were finally observed in comparison to their WT controls and independent of caloric intake. Additionally, APOA4-Tg mice exhibited increased energy expenditure at several time points when measured during the 10-week HFD feeding. Thus, overexpression of APOA4 in the small intestine and maintenance of elevated levels of plasma APOA4 appear to correlate with elevation of UCP1-dependent BAT thermogenesis and subsequent protection against HFD-induced obesity in mice.
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Affiliation(s)
- Zachary LaRussa
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Hsuan-Chih N Kuo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Kathryn West
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Zhijun Shen
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Kevin Wisniewski
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA
| | - Karen T Coschigano
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Chunmin C Lo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
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5
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Wen Y, Chen YQ, Konrad RJ. The Regulation of Triacylglycerol Metabolism and Lipoprotein Lipase Activity. Adv Biol (Weinh) 2022; 6:e2200093. [PMID: 35676229 DOI: 10.1002/adbi.202200093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/03/2022] [Indexed: 01/28/2023]
Abstract
Triacylglycerol (TG) metabolism is tightly regulated to maintain a pool of TG within circulating lipoproteins that can be hydrolyzed in a tissue-specific manner by lipoprotein lipase (LPL) to enable the delivery of fatty acids to adipose or oxidative tissues as needed. Elevated serum TG concentrations, which result from a deficiency of LPL activity or, more commonly, an imbalance in the regulation of tissue-specific LPL activities, have been associated with an increased risk of atherosclerotic cardiovascular disease through multiple studies. Among the most critical LPL regulators are the angiopoietin-like (ANGPTL) proteins ANGPTL3, ANGPTL4, and ANGPTL8, and a number of different apolipoproteins including apolipoprotein A5 (ApoA5), apolipoprotein C2 (ApoC2), and apolipoprotein C3 (ApoC3). These ANGPTLs and apolipoproteins work together to orchestrate LPL activity and therefore play pivotal roles in TG partitioning, hydrolysis, and utilization. This review summarizes the mechanisms of action, epidemiological findings, and genetic data most relevant to these ANGPTLs and apolipoproteins. The interplay between these important regulators of TG metabolism in both fasted and fed states is highlighted with a holistic view toward understanding key concepts and interactions. Strategies for developing safe and effective therapeutics to reduce circulating TG by selectively targeting these ANGPTLs and apolipoproteins are also discussed.
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Affiliation(s)
- Yi Wen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - Yan Q Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
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6
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Ueda M. Familial chylomicronemia syndrome: importance of diagnostic vigilance. Transl Pediatr 2022; 11:1588-1594. [PMID: 36345451 PMCID: PMC9636463 DOI: 10.21037/tp-22-488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/14/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Masako Ueda
- Department of Medicine, The University of Pennsylvania, Philadelphia, PA, USA
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7
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Liver-specific overexpression of lipoprotein lipase improves glucose metabolism in high-fat diet-fed mice. PLoS One 2022; 17:e0274297. [PMID: 36099304 PMCID: PMC9469954 DOI: 10.1371/journal.pone.0274297] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 08/25/2022] [Indexed: 11/24/2022] Open
Abstract
The liver is the main organ that regulates lipid and glucose metabolism. Ectopic lipid accumulation in the liver impairs insulin sensitivity and glucose metabolism. Lipoprotein lipase (LPL), mainly expressed in the adipose tissue and muscle, is a key enzyme that regulates lipid metabolism via the hydrolysis of triglyceride in chylomicrons and very-low-density lipoproteins. Here, we aimed to investigate whether the suppression level of hepatic lipid accumulation via overexpression of LPL in mouse liver leads to improved metabolism. To overexpress LPL in the liver, we generated an LPL-expressing adenovirus (Ad) vector using an improved Ad vector that exhibited considerably lower hepatotoxicity (Ad-LPL). C57BL/6 mice were treated with Ad vectors and simultaneously fed a high-fat diet (HFD). Lipid droplet formation in the liver decreased in Ad-LPL-treated mice relative to that in control Ad vector-treated mice. Glucose tolerance and insulin resistance were remarkably improved in Ad-LPL-treated mice compared to those in control Ad vector-treated mice. The expression levels of fatty acid oxidation-related genes, such as peroxisome proliferator-activated receptor α, carnitine palmitoyltransferase 1, and acyl-CoA oxidase 1, were 1.7–2.0-fold higher in Ad-LPL-treated mouse livers than that in control Ad-vector-treated mouse livers. Furthermore, hepatic LPL overexpression partly maintained mitochondrial content in HFD-fed mice. These results indicate that LPL overexpression in the livers of HFD-fed mice attenuates the accumulation of lipid droplets in the liver and improves glucose metabolism. These findings may enable the development of new drugs to treat metabolic syndromes such as type 2 diabetes mellitus and non-alcoholic fatty liver disease.
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8
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Zhang R, Zhang K. An updated ANGPTL3-4-8 model as a mechanism of triglyceride partitioning between fat and oxidative tissues. Prog Lipid Res 2022; 85:101140. [PMID: 34793860 PMCID: PMC8760165 DOI: 10.1016/j.plipres.2021.101140] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 01/03/2023]
Abstract
In mammals, triglyceride (TG), the main form of lipids for storing and providing energy, is stored in white adipose tissue (WAT) after food intake, while during fasting it is routed to oxidative tissues (heart and skeletal muscle) for energy production, a process referred to as TG partitioning. Lipoprotein lipase (LPL), a rate-limiting enzyme in this fundamental physiological process, hydrolyzes circulating TG to generate free fatty acids that are taken up by peripheral tissues. The postprandial activity of LPL declines in oxidative tissues but rises in WAT, directing TG to WAT; the reverse is true during fasting. However, the molecular mechanism in regulating tissue-specific LPL activity during the fed-fast cycle has not been completely understood. Research on angiopoietin-like (ANGPTL) proteins (A3, A4, and A8) has resulted in an ANGPTL3-4-8 model to explain the TG partitioning between WAT and oxidative tissues. Food intake induces A8 expression in the liver and WAT. Liver A8 activates A3 by forming the A3-8 complex, which is then secreted into the circulation. The A3-8 complex acts in an endocrine manner to inhibit LPL in oxidative tissues. WAT A8 forms the A4-8 complex, which acts locally to block A4's LPL-inhibiting activity. Therefore, the postprandial activity of LPL is low in oxidative tissues but high in WAT, directing circulating TG to WAT. Conversely, during fasting, reduced A8 expression in the liver and WAT disables A3 from inhibiting oxidative-tissue LPL and restores WAT A4's LPL-inhibiting activity, respectively. Thus, the fasting LPL activity is high in oxidative tissues but low in WAT, directing TG to the former. According to the model, we hypothesize that A8 antagonism has the potential to simultaneously reduce TG and increase HDL-cholesterol plasma levels. Future research on A3, A4, and A8 can hopefully provide more insights into human health, disease, and therapeutics.
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Affiliation(s)
- Ren Zhang
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, 540 East Canfield Street, Detroit, MI 48201, USA.
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, 540 East Canfield Street, Detroit, MI 48201, USA
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Abstract
Triglyceride-rich lipoproteins deliver fatty acids to tissues for oxidation and for storage. Release of fatty acids from circulating lipoprotein triglycerides is carried out by lipoprotein lipase (LPL), thus LPL serves as a critical gatekeeper of fatty acid uptake into tissues. LPL activity is regulated by a number of extracellular proteins including three members of the angiopoietin-like family of proteins. In this review, we discuss our current understanding of how, where, and when ANGPTL3, ANGPTL4, and ANGPTL8 regulate lipoprotein lipase activity, with a particular emphasis on how these proteins interact with each other to coordinate triglyceride metabolism and fat partitioning.
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Affiliation(s)
- Kelli L Sylvers-Davie
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, Iowa
| | - Brandon S J Davies
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, Iowa
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10
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Shang R, Rodrigues B. Lipoprotein Lipase and Its Delivery of Fatty Acids to the Heart. Biomolecules 2021; 11:biom11071016. [PMID: 34356640 PMCID: PMC8301904 DOI: 10.3390/biom11071016] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/08/2021] [Accepted: 07/08/2021] [Indexed: 02/05/2023] Open
Abstract
Ninety percent of plasma fatty acids (FAs) are contained within lipoprotein-triglyceride, and lipoprotein lipase (LPL) is robustly expressed in the heart. Hence, LPL-mediated lipolysis of lipoproteins is suggested to be a key source of FAs for cardiac use. Lipoprotein clearance by LPL occurs at the apical surface of the endothelial cell lining of the coronary lumen. In the heart, the majority of LPL is produced in cardiomyocytes and subsequently is translocated to the apical luminal surface. Here, vascular LPL hydrolyzes lipoprotein-triglyceride to provide the heart with FAs for ATP generation. This article presents an overview of cardiac LPL, explains how the enzyme works, describes key molecules that regulate its activity and outlines how changes in LPL are brought about by physiological and pathological states such as fasting and diabetes, respectively.
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Liu Y, Li H, Wang S, Yin W, Wang Z. Ibrolipim attenuates early-stage nephropathy in diet-induced diabetic minipigs: Focus on oxidative stress and fibrogenesis. Biomed Pharmacother 2020; 129:110321. [PMID: 32535382 DOI: 10.1016/j.biopha.2020.110321] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 05/19/2020] [Accepted: 05/23/2020] [Indexed: 12/27/2022] Open
Abstract
It is well-recognized that hyperlipidemia and lipid peroxidation contribute to the progression of diabetic nephropathy (DN), which is associated with oxidative stress (OS) and fibrotic lesions. Ibrolipim, a specific lipoprotein lipase activator, has been proved to reduce hyperglycemia and hyperlipidemia, suppress renal lipid deposition, and also protect renal damage. However, the underlying mechanisms of its renoprotective effect are not clearly elaborated. Herein, the present study was to identify whether the putative mechanism of Ibrolipim was related to OS and fibrogenesis in diabetic minipigs fed by high-sucrose and high-fat diet (HSFD) with or without Ibrolipim for 5 months. Compared with the normal control diet, nutrient stress induced by HSFD caused moderate glomerulosclerosis and tubulointerstitial fibrosis, and promoted renal ultrastructural and functional abnormalities. These abnormalities were correlated with renal OS and fibrogenesis characterized by the increased levels of reactive oxygen species (ROS), malondialdehyde, hydroxyproline, collagen type Ⅳ alpha 1 and fibronectin, and decreased contents of reduced glutathione and total antioxidant capacity in kidneys. Ibrolipim significantly ameliorated these abnormalities in HSFD-fed minipigs. In addition, Ibrolipim diminished HSFD-induced nicotinamide-adenine dinucleotide phosphate oxidase-4 activation to reduce ROS production, and enhanced the expression and activity of antioxidant enzymes (i.e. superoxide dismutase 1, catalase and glutathione peroxidase 1) to increase ROS elimination, resulting in obvious suppression of renal OS. Meanwhile, Ibrolipim not only inhibited the upregulation of transforming growth factor-β1 but also partially reversed the downregulation of matrix metalloproteinase 2, and then prevented extracellular matrix (ECM) accumulation. Taken together, Ibrolipim exhibits anti-oxidative and anti-fibrotic effects via modulating the rebalance of renal ROS and ECM metabolism, and ultimately attenuates the progression of nephropathy in diet-induced diabetic minipigs.
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Affiliation(s)
- Yi Liu
- Department of Medical Technology, Medical College, Shaoguan University, Shaoguan 512026, Guangdong, China
| | - Hongguang Li
- Department of Medical Technology, Medical College, Shaoguan University, Shaoguan 512026, Guangdong, China
| | - Shuzhi Wang
- School of Pharmacy, University of South China, Hengyang 421001, Hunan, China; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, Hunan, China
| | - Weidong Yin
- School of Pharmacy, University of South China, Hengyang 421001, Hunan, China; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, Hunan, China
| | - Zongbao Wang
- School of Pharmacy, University of South China, Hengyang 421001, Hunan, China; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, Hunan, China.
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12
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Kirby DJ, Buchalter DB, Anil U, Leucht P. DHEA in bone: the role in osteoporosis and fracture healing. Arch Osteoporos 2020; 15:84. [PMID: 32504237 DOI: 10.1007/s11657-020-00755-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/07/2020] [Indexed: 02/03/2023]
Abstract
Dehydroepiandrosterone (DHEA) is a metabolic intermediate in the biosynthesis of estrogens and androgens with a past clouded in controversy and bold claims. It was once touted as a wonder drug, a fountain of youth that could cure all ailments. However, in the 1980s DHEA was banned by the FDA given a lack of documented health benefits and long-term use data. DHEA had a revival in 1994 when it was released for open market sale as a nutritional supplement under the Dietary Supplement Health and Safety Act. Since that time, there has been encouraging research on the hormone, including randomized controlled trials and subsequent meta-analyses on various conditions that DHEA may benefit. Bone health has been of particular interest, as many of the metabolites of DHEA are known to be involved in bone homeostasis, specifically estrogen and testosterone. Studies demonstrate a significant association between DHEA and increased bone mineral density, likely due to DHEA's ability to increase osteoblast activity and insulin like growth factor 1 (IGF-1) expression. Interestingly, IGF-1 is also known to improve fracture healing, though DHEA, a potent stimulator of IGF-1, has never been tested in this scenario. The aim of this review is to discuss the history and mechanisms of DHEA as they relate to the skeletal system, and to evaluate if DHEA has any role in treating fractures.
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Affiliation(s)
- David J Kirby
- Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, 301 E 17th St, New York, NY, 10003, USA.
| | - Daniel B Buchalter
- Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, 301 E 17th St, New York, NY, 10003, USA
| | - Utkarsh Anil
- Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, 301 E 17th St, New York, NY, 10003, USA
| | - Philipp Leucht
- Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, 301 E 17th St, New York, NY, 10003, USA
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13
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Zhu Q, Weng J, Shen M, Fish J, Shen Z, Coschigano KT, Davidson WS, Tso P, Shi H, Lo CC. Apolipoprotein A-IV Enhances Fatty Acid Uptake by Adipose Tissues of Male Mice via Sympathetic Activation. Endocrinology 2020; 161:5802681. [PMID: 32157301 PMCID: PMC7100924 DOI: 10.1210/endocr/bqaa042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/04/2020] [Indexed: 12/31/2022]
Abstract
Apolipoprotein A-IV (ApoA-IV) synthesized by the gut regulates lipid metabolism. Sympathetic innervation of adipose tissues also controls lipid metabolism. We hypothesized that ApoA-IV required sympathetic innervation to increase fatty acid (FA) uptake by adipose tissues and brown adipose tissue (BAT) thermogenesis. After 3 weeks feeding of either a standard chow diet or a high-fat diet (HFD), mice with unilateral denervation of adipose tissues received intraperitoneal administration of recombinant ApoA-IV protein and intravenous infusion of lipid mixture with radioactive triolein. In chow-fed mice, ApoA-IV administration increased FA uptake by intact BAT but not the contralateral denervated BAT or intact white adipose tissue (WAT). Immunoblots showed that, in chow-fed mice, ApoA-IV increased expression of lipoprotein lipase and tyrosine hydroxylase in both intact BAT and inguinal WAT (IWAT), while ApoA-IV enhanced protein levels of β3 adrenergic receptor, adipose triglyceride lipase, and uncoupling protein 1 in the intact BAT only. In HFD-fed mice, ApoA-IV elevated FA uptake by intact epididymal WAT (EWAT) but not intact BAT or IWAT. ApoA-IV increased sympathetic activity assessed by norepinephrine turnover (NETO) rate in BAT and EWAT of chow-fed mice, whereas it elevated NETO only in EWAT of HFD-fed mice. These observations suggest that, in chow-fed mice, ApoA-IV activates sympathetic activity of BAT and increases FA uptake by BAT via innervation, while in HFD-fed mice, ApoA-IV stimulates sympathetic activity of EWAT to shunt FAs into the EWAT.
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Affiliation(s)
- Qi Zhu
- Department of Biology, Miami University, Oxford, OH
| | - Jonathan Weng
- Department of Biomedical Sciences and Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH
| | - Minqian Shen
- Department of Biology, Miami University, Oxford, OH
| | - Jace Fish
- Department of Biomedical Sciences and Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH
| | - Zhujun Shen
- Department of Biomedical Sciences and Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH
| | - Karen T Coschigano
- Department of Biomedical Sciences and Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH
| | - W Sean Davidson
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH
| | - Haifei Shi
- Department of Biology, Miami University, Oxford, OH
| | - Chunmin C Lo
- Department of Biomedical Sciences and Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH
- Correspondence: Chunmin C Lo, Department of Biomedical Sciences, Irvine Hall 228, 1 Ohio University, Athens, OH 45701-2979. E-mail:
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14
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Ma F, Yang Y, Jiang M, Yin D, Liu K. Digestive enzyme activity of the Japanese grenadier anchovy Coilia nasus during spawning migration: influence of the migration distance and the water temperature. JOURNAL OF FISH BIOLOGY 2019; 95:1311-1319. [PMID: 31513288 DOI: 10.1111/jfb.14136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/11/2019] [Indexed: 06/10/2023]
Abstract
In this study, we investigated the activity levels of two major digestive enzymes (pepsin and lipase) in the commercially important Japanese grenadier anchovy Coilia nasus during its upstream migration to analyse the digestive physiological responses to starvation and to analyse the influence of the water temperature on enzyme activity. Water temperature had a significant effect on pepsin activity, while long-term starvation resulted in a significant decrease in pepsin activity. As starvation continued, however, a slight increase in pepsin activity between the Wuhu (440 river km) and Anqing (620 river km) regions may indicate that C. nasus had refeeding behaviour due to its large expenditure of energy reserves. In contrast, lipase activity was not significantly affected by the water temperature but the effect of fasting increased as much as 13% of lipase activity from the Chongming region (20 river km) to Anqing region, suggesting that the stored lipids of grenadier anchovy were mobilised to meet energy requirements of upstream migration activity and gonad development. Lipid mobilisation activated lipoprotein lipase (LPL; proteins with lipase activity) to hydrolyse triacylglycerides (TAG), which is the first step of lipid assimilation and obtained energy from fatty acids under fasting conditions. Therefore, the increased lipase activity is attributed mainly to the lipase that is involved in endogenous lipid hydrolysis. Grenadier anchovy appears to adapt to long-term starvation during migration and the increased lipase activity may indicate a crucial effect on lipid metabolism. This study demonstrated that distinct alterations occur in pepsin and lipase activities during the spawning migration of grenadier anchovy due to exogenous nutrition and endogenous metabolism. Furthermore, it provides a basis for further research on the digestive physiology and energy metabolism in this species.
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Affiliation(s)
- Fengjiao Ma
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Yanping Yang
- Scientific Observing and Experimental Station of Fishery Resources and Environment in the Lower Reaches of the Changjiang River, Ministry of Agriculture and Rural Affaris, Freshwater Fisheries Research Center, CAFS, Wuxi, China
| | - Min Jiang
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Denghua Yin
- Scientific Observing and Experimental Station of Fishery Resources and Environment in the Lower Reaches of the Changjiang River, Ministry of Agriculture and Rural Affaris, Freshwater Fisheries Research Center, CAFS, Wuxi, China
| | - Kai Liu
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
- Scientific Observing and Experimental Station of Fishery Resources and Environment in the Lower Reaches of the Changjiang River, Ministry of Agriculture and Rural Affaris, Freshwater Fisheries Research Center, CAFS, Wuxi, China
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15
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Colliva A, Braga L, Giacca M, Zacchigna S. Endothelial cell-cardiomyocyte crosstalk in heart development and disease. J Physiol 2019; 598:2923-2939. [PMID: 30816576 PMCID: PMC7496632 DOI: 10.1113/jp276758] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 01/29/2019] [Indexed: 12/15/2022] Open
Abstract
The crosstalk between endothelial cells and cardiomyocytes has emerged as a requisite for normal cardiac development, but also a key pathogenic player during the onset and progression of cardiac disease. Endothelial cells and cardiomyocytes are in close proximity and communicate through the secretion of paracrine signals, as well as through direct cell-to-cell contact. Here, we provide an overview of the endothelial cell-cardiomyocyte interactions controlling heart development and the main processes affecting the heart in normal and pathological conditions, including ischaemia, remodelling and metabolic dysfunction. We also discuss the possible role of these interactions in cardiac regeneration and encourage the further improvement of in vitro models able to reproduce the complex environment of the cardiac tissue, in order to better define the mechanisms by which endothelial cells and cardiomyocytes interact with a final aim of developing novel therapeutic opportunities.
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Affiliation(s)
- Andrea Colliva
- Cardiovascular Biology Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano, 34149, Trieste, Italy
| | - Luca Braga
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano, 34149, Trieste, Italy
| | - Mauro Giacca
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano, 34149, Trieste, Italy.,Biotechnology Development Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano, 34149, Trieste, Italy
| | - Serena Zacchigna
- Cardiovascular Biology Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano, 34149, Trieste, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, 34149, Trieste, Italy
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16
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Angiopoietin-Like 3 (ANGPTL3) and Atherosclerosis: Lipid and Non-Lipid Related Effects. J Cardiovasc Dev Dis 2018; 5:jcdd5030039. [PMID: 30011918 PMCID: PMC6162638 DOI: 10.3390/jcdd5030039] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 01/13/2023] Open
Abstract
Genetic and clinical studies have demonstrated that loss-of-function variants in the angiopoietin-like 3 (ANGPTL3) gene are associated with decreased plasma levels of triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), which leads to a significant reduction in cardiovascular risk. For this reason, ANGPTL3 is considered an important new pharmacological target for the treatment of cardiovascular diseases (CVDs) together with more conventional lipid lowering therapies, such as statins and anti proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies. Experimental evidence demonstrates that anti-ANGPTL3 therapies have an important anti-atherosclerotic effect. Results from phase I clinical trials with a monoclonal anti-ANGPTL3 antibody (evinacumab) and anti-sense oligonucleotide (ASO) clearly show a significant lipid lowering effect. In addition, from the analysis of the protein structure of ANGPTL3, it has been hypothesized that, beyond its inhibitory activity on lipoprotein and endothelial lipases, this molecule may have a pro-inflammatory, pro-angiogenic effect and a negative effect on cholesterol efflux, implying additional pro-atherosclerotic properties. In the future, data from phase II clinical trials and additional experimental evidence will help to define the efficacy and the additional anti-atherosclerotic properties of anti-ANGPTL3 therapies beyond the already available lipid lowering therapies.
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17
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Frutos P, Toral P, Hervás G. Individual variation of the extent of milk fat depression in dairy ewes fed fish oil: Milk fatty acid profile and mRNA abundance of candidate genes involved in mammary lipogenesis. J Dairy Sci 2017; 100:9611-9622. [DOI: 10.3168/jds.2017-13354] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/19/2017] [Indexed: 12/27/2022]
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18
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He C, Hu X, Jung RS, Larsson M, Tu Y, Duarte-Vogel S, Kim P, Sandoval NP, Price TR, Allan CM, Raney B, Jiang H, Bensadoun A, Walzem RL, Kuo RI, Beigneux AP, Fong LG, Young SG. Lipoprotein lipase reaches the capillary lumen in chickens despite an apparent absence of GPIHBP1. JCI Insight 2017; 2:96783. [PMID: 29046479 DOI: 10.1172/jci.insight.96783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 09/11/2017] [Indexed: 12/17/2022] Open
Abstract
In mammals, GPIHBP1 is absolutely essential for transporting lipoprotein lipase (LPL) to the lumen of capillaries, where it hydrolyzes the triglycerides in triglyceride-rich lipoproteins. In all lower vertebrate species (e.g., birds, amphibians, reptiles, fish), a gene for LPL can be found easily, but a gene for GPIHBP1 has never been found. The obvious question is whether the LPL in lower vertebrates is able to reach the capillary lumen. Using purified antibodies against chicken LPL, we showed that LPL is present on capillary endothelial cells of chicken heart and adipose tissue, colocalizing with von Willebrand factor. When the antibodies against chicken LPL were injected intravenously into chickens, they bound to LPL on the luminal surface of capillaries in heart and adipose tissue. LPL was released rapidly from chicken hearts with an infusion of heparin, consistent with LPL being located inside blood vessels. Remarkably, chicken LPL bound in a specific fashion to mammalian GPIHBP1. However, we could not identify a gene for GPIHBP1 in the chicken genome, nor could we identify a transcript for GPIHBP1 in a large chicken RNA-seq data set. We conclude that LPL reaches the capillary lumen in chickens - as it does in mammals - despite an apparent absence of GPIHBP1.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Tara R Price
- Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, Texas, USA
| | | | - Brian Raney
- University of California, Santa Cruz Genomics Institute and
| | - Haibo Jiang
- Department of Medicine and.,Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, Western Australia, Perth, Australia
| | - André Bensadoun
- Division of Nutritional Science, Cornell University, Ithaca, New York, USA
| | - Rosemary L Walzem
- Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, Texas, USA
| | - Richard I Kuo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | - Stephen G Young
- Department of Medicine and.,Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
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19
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Kanaki M, Tiniakou I, Thymiakou E, Kardassis D. Physical and functional interactions between nuclear receptor LXRα and the forkhead box transcription factor FOXA2 regulate the response of the human lipoprotein lipase gene to oxysterols in hepatic cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:848-860. [PMID: 28576574 DOI: 10.1016/j.bbagrm.2017.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/17/2017] [Accepted: 05/29/2017] [Indexed: 11/30/2022]
Abstract
Lipoprotein lipase (LPL) catalyzes the hydrolysis of triglycerides from triglyceride-rich lipoproteins such as VLDL and chylomicrons in the circulation. Mutations in LPL or its activator apolipoprotein C-II cause hypertriglyceridemia in humans and animal models. The levels of LPL in the liver are low but they can be strongly induced by a high cholesterol diet or by synthetic ligands of Liver X Receptors (LXRs). However, the mechanism by which LXRs activate the human LPL gene is unknown. In the present study we show that LXR agonists increased the mRNA and protein levels as well as the promoter activity of human LPL in HepG2 cells. A promoter deletion analysis defined the proximal -109/-28 region, which contains a functional FOXA2 element, as essential for transactivation by ligand-activated LXRα/RXRα heterodimers. Silencing of endogenous FOXA2 in HepG2 cells by siRNAs or by treatment with insulin compromised the induction of the LPL gene by LXR agonists whereas mutations in the FOXA2 site abolished the synergistic transactivation of the LPL promoter by LXRα/RXRα and FOXA2. Physical and functional interactions between LXRα and FOXA2 were established in vitro and ex vivo. In summary, the present study revealed a novel mechanism of human LPL gene induction by oxysterols in the liver with is based on physical and functional interactions between transcription factors LXRα and FOXA2. This mechanism, which may not be restricted to the LPL gene, is critically important for a better understanding of the regulation of cholesterol and triglyceride metabolism in the liver under healthy or pathological states.
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Affiliation(s)
- Maria Kanaki
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece
| | - Ioanna Tiniakou
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece
| | - Efstathia Thymiakou
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece
| | - Dimitris Kardassis
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece,.
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20
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Kanaki M, Kardassis D. Regulation of the human lipoprotein lipase gene by the forkhead box transcription factor FOXA2/HNF-3β in hepatic cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:327-336. [DOI: 10.1016/j.bbagrm.2017.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/13/2017] [Accepted: 01/13/2017] [Indexed: 12/11/2022]
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21
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Transcriptomic Analysis of THP-1 Macrophages Exposed to Lipoprotein Hydrolysis Products Generated by Lipoprotein Lipase. Lipids 2017; 52:189-205. [DOI: 10.1007/s11745-017-4238-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 02/02/2017] [Indexed: 11/25/2022]
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22
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Hu X, Sleeman MW, Miyashita K, Linton MF, Allan CM, He C, Larsson M, Tu Y, Sandoval NP, Jung RS, Mapar A, Machida T, Murakami M, Nakajima K, Ploug M, Fong LG, Young SG, Beigneux AP. Monoclonal antibodies that bind to the Ly6 domain of GPIHBP1 abolish the binding of LPL. J Lipid Res 2016; 58:208-215. [PMID: 27875259 DOI: 10.1194/jlr.m072462] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 10/31/2016] [Indexed: 01/18/2023] Open
Abstract
GPIHBP1, an endothelial cell protein, binds LPL in the interstitial spaces and shuttles it to its site of action inside blood vessels. For years, studies of human GPIHBP1 have been hampered by an absence of useful antibodies. We reasoned that monoclonal antibodies (mAbs) against human GPIHBP1 would be useful for 1) defining the functional relevance of GPIHBP1's Ly6 and acidic domains to the binding of LPL; 2) ascertaining whether human GPIHBP1 is expressed exclusively in capillary endothelial cells; and 3) testing whether GPIHBP1 is detectable in human plasma. Here, we report the development of a panel of human GPIHBP1-specific mAbs. Two mAbs against GPIHBP1's Ly6 domain, RE3 and RG3, abolished LPL binding, whereas an antibody against the acidic domain, RF4, did not. Also, mAbs RE3 and RG3 bound with reduced affinity to a mutant GPIHBP1 containing an Ly6 domain mutation (W109S) that abolishes LPL binding. Immunohistochemistry studies with the GPIHBP1 mAbs revealed that human GPIHBP1 is expressed only in capillary endothelial cells. Finally, we created an ELISA that detects GPIHBP1 in human plasma. That ELISA should make it possible for clinical lipidologists to determine whether plasma GPIHBP1 levels are a useful biomarker of metabolic or vascular disease.
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Affiliation(s)
- Xuchen Hu
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Mark W Sleeman
- Monash Biomedicine Discovery Institute and Antibody Technologies Facility, Monash University, Victoria, Australia
| | - Kazuya Miyashita
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - MacRae F Linton
- Departments of Medicine and Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Christopher M Allan
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Cuiwen He
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Mikael Larsson
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Yiping Tu
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Norma P Sandoval
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Rachel S Jung
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Alaleh Mapar
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Tetsuo Machida
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Masami Murakami
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Katsuyuki Nakajima
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Loren G Fong
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
| | - Stephen G Young
- Departments of Medicine University of California Los Angeles, Los Angeles, CA .,Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Anne P Beigneux
- Departments of Medicine University of California Los Angeles, Los Angeles, CA
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23
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Toral P, Hervás G, Suárez-Vega A, Arranz J, Frutos P. Isolation of RNA from milk somatic cells as an alternative to biopsies of mammary tissue for nutrigenomic studies in dairy ewes. J Dairy Sci 2016; 99:8461-8471. [DOI: 10.3168/jds.2016-11184] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/26/2016] [Indexed: 12/13/2022]
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24
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Wan A, Rodrigues B. Endothelial cell-cardiomyocyte crosstalk in diabetic cardiomyopathy. Cardiovasc Res 2016; 111:172-83. [PMID: 27288009 DOI: 10.1093/cvr/cvw159] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/21/2016] [Indexed: 12/19/2022] Open
Abstract
The incidence of diabetes is increasing globally, with cardiovascular disease accounting for a substantial number of diabetes-related deaths. Although atherosclerotic vascular disease is a primary reason for this cardiovascular dysfunction, heart failure in patients with diabetes might also be an outcome of an intrinsic heart muscle malfunction, labelled diabetic cardiomyopathy. Changes in cardiomyocyte metabolism, which encompasses a shift to exclusive fatty acid utilization, are considered a leading stimulus for this cardiomyopathy. In addition to cardiomyocytes, endothelial cells (ECs) make up a significant proportion of the heart, with the majority of ATP generation in these cells provided by glucose. In this review, we will discuss the metabolic machinery that drives energy metabolism in the cardiomyocyte and EC, its breakdown following diabetes, and the research direction necessary to assist in devising novel therapeutic strategies to prevent or delay diabetic heart disease.
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Affiliation(s)
- Andrea Wan
- Faculty of Pharmaceutical Sciences, The University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, The University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
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25
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Klinger SC, Højland A, Jain S, Kjolby M, Madsen P, Svendsen AD, Olivecrona G, Bonifacino JS, Nielsen MS. Polarized trafficking of the sorting receptor SorLA in neurons and MDCK cells. FEBS J 2016; 283:2476-93. [PMID: 27192064 DOI: 10.1111/febs.13758] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 05/03/2016] [Accepted: 05/13/2016] [Indexed: 01/19/2023]
Abstract
The sorting receptor SorLA is highly expressed in neurons and is also found in other polarized cells. The receptor has been reported to participate in the trafficking of several ligands, some of which are linked to human diseases, including the amyloid precursor protein, TrkB, and Lipoprotein Lipase (LpL). Despite this, only the trafficking in nonpolarized cells has been described so far. Due to the many differences between polarized and nonpolarized cells, we examined the localization and trafficking of SorLA in epithelial Madin-Darby canine kidney (MDCK) cells and rat hippocampal neurons. We show that SorLA is mainly found in sorting endosomes and on the basolateral surface of MDCK cells and in the somatodendritic domain of neurons. This polarized distribution of SorLA respectively depends on an acidic cluster and an extended version of this cluster and involves the cellular adaptor complex AP-1. Furthermore, we show that SorLA can mediate transcytosis across a tight cell layer.
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Affiliation(s)
- Stine C Klinger
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark.,Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anne Højland
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
| | - Shweta Jain
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Mads Kjolby
- Department of Biomedicine, The MIND Centre, Aarhus University, Denmark.,Department of Biomedicine, The Danish Diabetes Academy, Aarhus University, Denmark
| | - Peder Madsen
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
| | - Anna Dorst Svendsen
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
| | - Gunilla Olivecrona
- Department of Medical Biosciences, Physiological Chemistry, Umeå University, Sweden
| | - Juan S Bonifacino
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Morten S Nielsen
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
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Microenvironmental Control of Adipocyte Fate and Function. Trends Cell Biol 2016; 26:745-755. [PMID: 27268909 DOI: 10.1016/j.tcb.2016.05.005] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/09/2016] [Accepted: 05/16/2016] [Indexed: 01/07/2023]
Abstract
The properties of tissue-specific microenvironments vary widely in the human body and demonstrably influence the structure and function of many cell types. Adipocytes are no exception, responding to cues in specialized niches to perform vital metabolic and endocrine functions. The adipose microenvironment is remodeled during tissue expansion to maintain the structural and functional integrity of the tissue and disrupted remodeling in obesity contributes to the progression of metabolic syndrome, breast cancer, and other malignancies. The increasing incidence of these obesity-related diseases and the recent focus on improved in vitro models of human tissue biology underscore growing interest in the regulatory role of adipocyte microenvironments in health and disease.
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Wang M, Xu D, Liu K, Yang J, Xu P. Molecular cloning and expression analysis on LPL of Coilia nasus. Gene 2016; 583:147-159. [DOI: 10.1016/j.gene.2016.02.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/22/2015] [Accepted: 02/10/2016] [Indexed: 11/29/2022]
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Choi M, Chaudhari HN, Ji YR, Ryoo ZY, Kim SW, Yun JW. Effect of estrogen on expression of prohibitin in white adipose tissue and liver of diet-induced obese rats. Mol Cell Biochem 2015; 407:181-96. [DOI: 10.1007/s11010-015-2468-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/29/2015] [Indexed: 12/11/2022]
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Intrinsic and extrinsic regulation of cardiac lipoprotein lipase following diabetes. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:163-71. [PMID: 25463481 DOI: 10.1016/j.bbalip.2014.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 02/07/2023]
Abstract
Cardiac lipoprotein lipase (LPL) is a pivotal enzyme controlling heart metabolism by providing the majority of fatty acids required by this organ. From activation in cardiomyocytes to secretion to the vascular lumen, cardiac LPL is regulated by multiple pathways, which are altered during diabetes. Hence, dimerization/activation of LPL is modified following diabetes, a process controlled by lipase maturation factor 1. The role of AMP-activated protein kinase, protein kinase D, and heparan sulfate proteoglycans, intrinsic factors that regulate the intracellular transport of LPL is also shifted, and is discussed. More recent studies have identified several exogenous factors released from endothelial cells (EC) and adipose tissue that are required for proper functioning of LPL. In response to hyperglycemia, both active and latent heparanase are released from EC to facilitate LPL secretion. Diabetes also increased the expression of glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) in EC, which mediates the transport of LPL across EC. Angiopoietin-like protein 4 secreted from the adipose tissue has the potential to reduce coronary LPL activity. Knowledge of these intrinsic and extrinsic factors could be used develop therapeutic targets to normalize LPL function, and maintain cardiac energy homeostasis after diabetes.
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Yang Y, Thyagarajan N, Coady BM, Brown RJ. Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase. Biochem Biophys Res Commun 2014; 451:632-6. [PMID: 25130461 DOI: 10.1016/j.bbrc.2014.08.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 08/08/2014] [Indexed: 12/14/2022]
Abstract
Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL.
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Affiliation(s)
- Yanbo Yang
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Narmadaa Thyagarajan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Breanne M Coady
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Robert J Brown
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada.
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Wang Y, Chiu APL, Neumaier K, Wang F, Zhang D, Hussein B, Lal N, Wan A, Liu G, Vlodavsky I, Rodrigues B. Endothelial cell heparanase taken up by cardiomyocytes regulates lipoprotein lipase transfer to the coronary lumen after diabetes. Diabetes 2014; 63:2643-55. [PMID: 24608441 DOI: 10.2337/db13-1842] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
After diabetes, the heart has a singular reliance on fatty acid (FA) for energy production, which is achieved by increased coronary lipoprotein lipase (LPL) that breaks down circulating triglycerides. Coronary LPL originates from cardiomyocytes, and to translocate to the vascular lumen, the enzyme requires liberation from myocyte surface heparan sulfate proteoglycans (HSPGs), an activity that needs to be sustained after chronic hyperglycemia. We investigated the mechanism by which endothelial cells (EC) and cardiomyocytes operate together to enable continuous translocation of LPL after diabetes. EC were cocultured with myocytes, exposed to high glucose, and uptake of endothelial heparanase into myocytes was determined. Upon uptake, the effect of nuclear entry of heparanase was also investigated. A streptozotocin model of diabetes was used to expand our in vitro observations. In high glucose, EC-derived latent heparanase was taken up by cardiomyocytes by a caveolae-dependent pathway using HSPGs. This latent heparanase was converted into an active form in myocyte lysosomes, entered the nucleus, and upregulated gene expression of matrix metalloproteinase-9. The net effect was increased shedding of HSPGs from the myocyte surface, releasing LPL for its onwards translocation to the coronary lumen. EC-derived heparanase regulates the ability of the cardiomyocyte to send LPL to the coronary lumen. This adaptation, although acutely beneficial, could be catastrophic chronically because excess FA causes lipotoxicity. Inhibiting heparanase function could offer a new strategy for managing cardiomyopathy observed after diabetes.
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Affiliation(s)
- Ying Wang
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Amy Pei-Ling Chiu
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Katharina Neumaier
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Fulong Wang
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Dahai Zhang
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Bahira Hussein
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Nathaniel Lal
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Andrea Wan
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - George Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Peking University, Beijing, China
| | - Israel Vlodavsky
- Cancer and Vascular Biology Research Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
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Kersten S. Physiological regulation of lipoprotein lipase. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:919-33. [PMID: 24721265 DOI: 10.1016/j.bbalip.2014.03.013] [Citation(s) in RCA: 335] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/27/2014] [Accepted: 03/30/2014] [Indexed: 01/01/2023]
Abstract
The enzyme lipoprotein lipase (LPL), originally identified as the clearing factor lipase, hydrolyzes triglycerides present in the triglyceride-rich lipoproteins VLDL and chylomicrons. LPL is primarily expressed in tissues that oxidize or store fatty acids in large quantities such as the heart, skeletal muscle, brown adipose tissue and white adipose tissue. Upon production by the underlying parenchymal cells, LPL is transported and attached to the capillary endothelium by the protein GPIHBP1. Because LPL is rate limiting for plasma triglyceride clearance and tissue uptake of fatty acids, the activity of LPL is carefully controlled to adjust fatty acid uptake to the requirements of the underlying tissue via multiple mechanisms at the transcriptional and post-translational level. Although various stimuli influence LPL gene transcription, it is now evident that most of the physiological variation in LPL activity, such as during fasting and exercise, appears to be driven via post-translational mechanisms by extracellular proteins. These proteins can be divided into two main groups: the liver-derived apolipoproteins APOC1, APOC2, APOC3, APOA5, and APOE, and the angiopoietin-like proteins ANGPTL3, ANGPTL4 and ANGPTL8, which have a broader expression profile. This review will summarize the available literature on the regulation of LPL activity in various tissues, with an emphasis on the response to diverse physiological stimuli.
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Affiliation(s)
- Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD Wageningen, The Netherlands
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33
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Frayn KN, Karpe F. Regulation of human subcutaneous adipose tissue blood flow. Int J Obes (Lond) 2013; 38:1019-26. [PMID: 24166067 DOI: 10.1038/ijo.2013.200] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 09/12/2013] [Accepted: 09/21/2013] [Indexed: 12/14/2022]
Abstract
Subcutaneous adipose tissue represents about 85% of all body fat. Its major metabolic role is the regulated storage and mobilization of lipid energy. It stores lipid in the form of triacylglycerol (TG), which is mobilized, as required for use by other tissues, in the form of non-esterified fatty acids (NEFA). Neither TG nor NEFA are soluble to any extent in water, and their transport to and out of the tissue requires specialized transport mechanisms and adequate blood flow. Subcutaneous adipose tissue blood flow (ATBF) is therefore tightly linked to the tissue's metabolic functioning. ATBF is relatively high (in the fasting state, similar to that of resting skeletal muscle, when expressed per 100 g tissue) and changes markedly in different physiological states. Those most studied are after ingestion of a meal, when there is normally a marked rise in ATBF, and exercise, when ATBF also increases. Pharmacological studies have helped to define the physiological regulation of ATBF. Adrenergic influences predominate in most situations, but nevertheless the regulation of ATBF is complex and depends on the interplay of many different systems. ATBF is downregulated in obesity (when expressed per 100 g tissue), and its responsiveness to meal intake is reduced. However, there is little evidence that this leads to adipose tissue hypoxia in human obesity, and we suggest that, like the downregulation of catecholamine-stimulated lipolysis seen in obesity, the reduction in ATBF represents an adaptation to the increased fat mass. Most information on ATBF has been obtained from studying the subcutaneous abdominal fat depot, but more limited information on lower-body fat depots suggests some similarities, but also some differences: in particular, marked alpha-adrenergic tone, which can reduce the femoral ATBF response to adrenergic stimuli.
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Affiliation(s)
- K N Frayn
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Oxford, UK
| | - F Karpe
- 1] Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Oxford, UK [2] National Institute for Health Research, Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
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Boutinaud M, Galio L, Lollivier V, Finot L, Wiart S, Esquerré D, Devinoy E. Unilateral once daily milking locally induces differential gene expression in both mammary tissue and milk epithelial cells revealing mammary remodeling. Physiol Genomics 2013; 45:973-85. [PMID: 23983197 DOI: 10.1152/physiolgenomics.00059.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Once daily milking reduces milk yield, but the underlying mechanisms are not yet fully understood. Local regulation due to milk stasis in the tissue may contribute to this effect, but such mechanisms have not yet been fully described. To challenge this hypothesis, one udder half of six Holstein dairy cows was milked once a day (ODM), and the other twice a day (TDM). On the 8th day of unilateral ODM, mammary epithelial cells (MEC) were purified from the milk using immunomagnetic separation. Mammary biopsies were harvested from both udder halves. The differences in transcript profiles between biopsies from ODM and TDM udder halves were analyzed by a 22k bovine oligonucleotide array, revealing 490 transcripts that were differentially expressed. The principal category of upregulated transcripts concerned mechanisms involved in cell proliferation and death. We further confirmed remodeling of the mammary tissue by immunohistochemistry, which showed less cell proliferation and more apoptosis in ODM udder halves. Gene expression analyzed by RT-qPCR in MEC purified from milk and mammary biopsies showed a common downregulation of six transcripts (ABCG2, FABP3, NUCB2, RNASE1 and 5, and SLC34A2) but also some discrepancies. First, none of the upregulated transcripts in biopsies varied in milk-purified MEC. Second, only milk-purified MEC showed significant LALBA downregulation, which suggests therefore that they correspond to a mammary epithelial cell subpopulation. Our results, obtained after unilateral milking, suggest that cell remodeling during ODM is due to a local effect, which may be triggered by milk accumulation.
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Affiliation(s)
- Marion Boutinaud
- INRA, UR1196 Génomique et Physiologie de la Lactation, Jouy-en-Josas, France
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Zheng JL, Luo Z, Liu CX, Chen QL, Tan XY, Zhu QL, Gong Y. Differential effects of acute and chronic zinc (Zn) exposure on hepatic lipid deposition and metabolism in yellow catfish Pelteobagrus fulvidraco. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 132-133:173-181. [PMID: 23523964 DOI: 10.1016/j.aquatox.2013.02.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/25/2013] [Accepted: 02/10/2013] [Indexed: 06/02/2023]
Abstract
The present study is conducted to determine the potential mechanisms of Zn on hepatic lipid deposition and metabolism for yellow catfish Pelteobagrus fulvidraco with 8-week chronic exposure to low Zn levels (Zn levels: 0.05, 0.35 and 0.86mg/l Zn, respectively) and 96-h acute exposure to a high Zn level (Zn level: 4.71mg/l Zn, respectively). For that purpose, hepatic lipid deposition and Zn accumulation, hepatic carnitine palmitoyltransferase I (CPT I) and lipoprotein lipase (LPL) activities, and the hepatic mRNA expression of ten genes involved in lipid metabolism are determined. Chronic (8 weeks) exposure to low Zn levels apparently increases hepatic lipid content, hepatosomatic index (HSI) (P<0.05) and LPL activity, and reduces hepatic CPT I activity. In contrast, the acute (96h) exposure to high Zn level reduces hepatic lipid content, HSI and LPL activity, and increases CPT I activity. The change of mRNA levels of genes related to lipid metabolism is Zn concentration-dependent. Pearson correlations among mRNA expression levels, lipid content, CPT I and LPL activities in liver are also observed in yellow catfish with the 8-week chronic Zn exposure. For the first time, our study demonstrates the effect of waterborne Zn exposure on lipid metabolism at the molecular levels in fish, which may contribute to understanding the mechanism of Zn-induced hepatic toxicity in fish.
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Affiliation(s)
- Jia-Lang Zheng
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070, China
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Zhang X, Wu C, Wu H, Sheng L, Su Y, Zhang X, Luan H, Sun G, Sun X, Tian Y, Ji Y, Guo P, Xu X. Anti-hyperlipidemic effects and potential mechanisms of action of the caffeoylquinic acid-rich Pandanus tectorius fruit extract in hamsters fed a high fat-diet. PLoS One 2013; 8:e61922. [PMID: 23613974 PMCID: PMC3628350 DOI: 10.1371/journal.pone.0061922] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 03/15/2013] [Indexed: 12/20/2022] Open
Abstract
Hyperlipidemia is considered to be one of the greatest risk factors contributing to the prevalence and severity of cardiovascular diseases. In this work, we investigated the anti-hyperlipidemic effect and potential mechanism of action of the Pandanus tectorius fruit extract in hamsters fed a high fat-diet (HFD). The n-butanol fraction of the P. tectorius fruit ethanol extract (PTF-b) was rich in caffeoylquinic acids (CQAs). Administration of PTF-b for 4 weeks effectively decreased retroperitoneal fat and the serum levels of total cholesterol (TC), triglycerides (TG) and low density lipoprotein-cholesterol (LDL-c) and hepatic TC and TG. The lipid signals (fatty acids, and cholesterol) in the liver as determined by nuclear magnetic resonance (NMR) were correspondingly reduced. Realtime quantitative PCR showed that the mRNA levels of PPARα and PPARα-regulated genes such as ACO, CPT1, LPL and HSL were largely enhanced by PTF-b. The transcription of LDLR, CYP7A1, and PPARγ was also upregulated. Treatment with PTF-b significantly stimulated the activation of AMP-activated protein kinase (AMPK) as well as the activity of serum and hepatic lipoprotein lipase (LPL). Together, these results suggest that administration of the PTF-b enriched in CQAs moderates hyperlipidemia and improves the liver lipid profile. These effects may be caused, at least in part, by increasing the expression of PPARα and its downstream genes and by upregulation of LPL and AMPK activities.
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Affiliation(s)
- Xiaopo Zhang
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Chongming Wu
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Haifeng Wu
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | | | - Yan Su
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- Research Centre on Life Sciences and Environment Sciences, Harbin University of Commerce, Harbin, China
| | - Xue Zhang
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- Research Centre on Life Sciences and Environment Sciences, Harbin University of Commerce, Harbin, China
| | - Hong Luan
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- Research Centre on Life Sciences and Environment Sciences, Harbin University of Commerce, Harbin, China
| | - Guibo Sun
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Xiaobo Sun
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Yu Tian
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Yubin Ji
- Research Centre on Life Sciences and Environment Sciences, Harbin University of Commerce, Harbin, China
| | - Peng Guo
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- * E-mail: (PG); (XX)
| | - Xudong Xu
- Pharmacology and Toxicology Research Center, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- * E-mail: (PG); (XX)
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Wang Y, Zhang D, Chiu APL, Wan A, Neumaier K, Vlodavsky I, Rodrigues B. Endothelial heparanase regulates heart metabolism by stimulating lipoprotein lipase secretion from cardiomyocytes. Arterioscler Thromb Vasc Biol 2013; 33:894-902. [PMID: 23471235 DOI: 10.1161/atvbaha.113.301309] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE After diabetes mellitus, transfer of lipoprotein lipase (LPL) from cardiomyocytes to the coronary lumen increases, and this requires liberation of LPL from the myocyte surface heparan sulfate proteoglycans with subsequent replenishment of this reservoir. At the lumen, LPL breaks down triglyceride to meet the increased demand of the heart for fatty acid. Here, we examined the contribution of coronary endothelial cells (ECs) toward regulation of cardiomyocyte LPL secretion. APPROACH AND RESULTS Bovine coronary artery ECs were exposed to high glucose, and the conditioned medium was used to treat cardiomyocytes. EC-conditioned medium liberated LPL from the myocyte surface, in addition to facilitating its replenishment. This effect was attributed to the increased heparanase content in EC-conditioned medium. Of the 2 forms of heparanase secreted from EC in response to high glucose, active heparanase released LPL from the myocyte surface, whereas latent heparanase stimulated reloading of LPL from an intracellular pool via heparan sulfate proteoglycan-mediated RhoA activation. CONCLUSIONS Endothelial heparanase is a participant in facilitating LPL increase at the coronary lumen. These observations provide an insight into the cross-talk between ECs and cardiomyocytes to regulate cardiac metabolism after diabetes mellitus.
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Affiliation(s)
- Ying Wang
- Faculty of Pharmaceutical Sciences, The University of British Columbia, 2405 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3
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Jiang J, Song X, Huang X, Wu J, Zhou W, Zheng H, Jiang Y. Effects of alfalfa meal on carcase quality and fat metabolism of Muscovy ducks. Br Poult Sci 2012; 53:681-8. [DOI: 10.1080/00071668.2012.731493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Kim MS, Wang Y, Rodrigues B. Lipoprotein lipase mediated fatty acid delivery and its impact in diabetic cardiomyopathy. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:800-8. [PMID: 22024251 DOI: 10.1016/j.bbalip.2011.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 09/15/2011] [Accepted: 10/03/2011] [Indexed: 01/29/2023]
Abstract
Although cardiovascular disease is the leading cause of diabetes-related death, its etiology is still not understood. The immediate change that occurs in the diabetic heart is altered energy metabolism where in the presence of impaired glucose uptake, glycolysis, and pyruvate oxidation, the heart switches to exclusively using fatty acids (FA) for energy supply. It does this by rapidly amplifying its lipoprotein lipase (LPL-a key enzyme, which hydrolyzes circulating lipoprotein-triglyceride to release FA) activity at the coronary lumen. An abnormally high capillary LPL could provide excess fats to the heart, leading to a number of metabolic, morphological, and mechanical changes, and eventually to cardiac disease. Unlike the initial response, chronic severe diabetes "turns off" LPL, this is also detrimental to cardiac function. In this review, we describe a number of post-translational mechanisms that influence LPL vesicle formation, actin cytoskeleton rearrangement, and transfer of LPL from cardiomyocytes to the vascular lumen to hydrolyze lipoprotein-triglyceride following diabetes. Appreciating the mechanism of how the heart regulates its LPL following diabetes should allow the identification of novel targets for therapeutic intervention, to prevent heart failure. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Min Suk Kim
- Molecular and Cellular Pharmacology, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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Wang Y, Puthanveetil P, Wang F, Kim MS, Abrahani A, Rodrigues B. Severity of diabetes governs vascular lipoprotein lipase by affecting enzyme dimerization and disassembly. Diabetes 2011; 60:2041-50. [PMID: 21646389 PMCID: PMC3142087 DOI: 10.2337/db11-0042] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE In diabetes, when glucose consumption is restricted, the heart adapts to use fatty acid (FA) exclusively. The majority of FA provided to the heart comes from the breakdown of circulating triglyceride (TG), a process catalyzed by lipoprotein lipase (LPL) located at the vascular lumen. The objective of the current study was to determine the mechanisms behind LPL processing and breakdown after moderate and severe diabetes. RESEARCH DESIGN AND METHODS To induce acute hyperglycemia, diazoxide, a selective, ATP-sensitive K(+) channel opener was used. For chronic diabetes, streptozotocin, a β-cell-specific toxin was administered at doses of 55 or 100 mg/kg to generate moderate and severe diabetes, respectively. Cardiac LPL processing into active dimers and breakdown at the vascular lumen was investigated. RESULTS After acute hyperglycemia and moderate diabetes, more LPL is processed into an active dimeric form, which involves the endoplasmic reticulum chaperone calnexin. Severe diabetes results in increased conversion of LPL into inactive monomers at the vascular lumen, a process mediated by FA-induced expression of angiopoietin-like protein 4 (Angptl-4). CONCLUSIONS In acute hyperglycemia and moderate diabetes, exaggerated LPL processing to dimeric, catalytically active enzyme increases coronary LPL, delivering more FA to the heart when glucose utilization is compromised. In severe chronic diabetes, to avoid lipid oversupply, FA-induced expression of Angptl-4 leads to conversion of LPL to inactive monomers at the coronary lumen to impede TG hydrolysis. Results from this study advance our understanding of how diabetes changes coronary LPL, which could contribute to cardiovascular complications seen with this disease.
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Liu Y, Wang ZB, Yin WD, Li QK, Cai MB, Yu J, Li HG, Zhang C, Zu XH. Preventive effect of Ibrolipim on suppressing lipid accumulation and increasing lipoprotein lipase in the kidneys of diet-induced diabetic minipigs. Lipids Health Dis 2011; 10:117. [PMID: 21762526 PMCID: PMC3155903 DOI: 10.1186/1476-511x-10-117] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 07/16/2011] [Indexed: 01/22/2023] Open
Abstract
Background The role of renal lipoprotein lipase (LPL) per se in kidney diseases is still controversial and obscure. The purpose of this study was to observe the preventive effects of Ibrolipim, a LPL activator, on lipid accumulation and LPL expression in the kidneys of minipigs fed a high-sucrose and high-fat diet (HSFD). Methods Male Chinese Bama minipigs were fed a control diet or HSFD with or without 0.1 g/kg/day Ibrolipim for 5 months. Body weight, plasma glucose, insulin, lipids, LPL activity, and urinary microalbumin were measured. Renal tissue was obtained for detecting LPL activity and contents of triglyceride and cholesterol, observing the renal lipid accumulation by Oil Red O staining, and examining the mRNA and protein expression of LPL by real time PCR, Western Blot and immunohistochemistry. Results Feeding HSFD to minipigs caused weight gain, hyperglycemia, hyperinsulinemia, hyperlipidemia and microalbuminuria. HSFD increased plasma LPL activity while it decreased the mRNA and protein expression and activity of LPL in the kidney. The increases in renal triglyceride and cholesterol contents were associated with the decrease in renal LPL activity of HSFD-fed minipigs. In contrast, supplementing Ibrolipim into HSFD lowered body weight, plasma glucose, insulin, triglyceride and urinary albumin concentrations while it increased plasma total cholesterol and HDL-C. Ibrolipim suppressed the renal accumulation of triglyceride and cholesterol, and stimulated the diet-induced down-regulation of LPL expression and activity in the kidney. Conclusions Ibrolipim exerts renoprotective and hypolipidemic effects via the increase in renal LPL activity and expression, and thus the increased expression and activity of renal LPL play a vital role in suppressing renal lipid accumulation and ameliorating proteinuria in diet-induced diabetic minipigs.
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Affiliation(s)
- Yi Liu
- Department of Laboratory Animal Science, University of South China, Hengyang, China
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Araki M, Fan J, Challah M, Bensadoun A, Yamada N, Honda K, Watanabe T. Transgenic rabbits expressing human lipoprotein lipase. Cytotechnology 2011; 33:93-9. [PMID: 19002816 DOI: 10.1023/a:1008115429679] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To study the functions of lipoprotein lipase (LPL) in lipid and lipoprotein metabolism and the relationship between LPL and atherosclerosis, we generated transgenic rabbits expressing the human LPL gene. A total of 4045 Japanese whiterabbit embryos were microinjected with a 3.8-kb SalI/HindIII fragment containing the chicken beta-actin promoter, human LPL cDNA and rabbit beta-globin with poly (A) signals, and then transplanted into 116 recipient rabbits. Of the 166 pups born, six pups were transgenic as confirmed by Southern blot analysis. ANorthern blot analysis revealed that human LPL was expressed by a number of tissues including the heart, kidney, adrenal gland and intestine. One transgenic rabbit showed up to 3-foldincreased LPL activity in post-heparin plasma compared to thatin nontransgenic rabbits. Human LPL expression in various tissues of transgenic rabbits was further elucidated by in situ hybridization and immunostaining. Since rabbits are superior to mice as a model of atherosclerosis, this transgenicrabbit model should provide a valuable tool for the study of LPL in lipid metabolism and atherosclerosis.
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Affiliation(s)
- M Araki
- Department of Pathology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, 305-8575, Japan
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Very-low-density lipoprotein: complex particles in cardiac energy metabolism. J Lipids 2011; 2011:189876. [PMID: 21773049 PMCID: PMC3136095 DOI: 10.1155/2011/189876] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 05/09/2011] [Indexed: 01/07/2023] Open
Abstract
The heart is a major consumer of energy and is able to utilise a wide range of substrates including lipids. Nonesterified fatty acids (NEFA) were thought to be a favoured carbon source, but their quantitative contribution is limited because of their relative histotoxicity. Circulating triacylglycerols (TAGs) in the form of chylomicrons (CMs) and very-low-density lipoprotein (VLDL) are an alternative source of fatty acids and are now believed to be important in cardiac metabolism. However, few studies on cardiac utilisation of VLDL have been performed and the role of VLDL in cardiac energy metabolism remains unclear. Hearts utilise VLDL to generate ATP, but the oxidation rate of VLDL-TAG is relatively low under physiological conditions; however, in certain pathological states switching of energy substrates occurs and VLDL may become a major energy source for hearts. We review research regarding myocardial utilisation of VLDL and suggest possible roles of VLDL in cardiac energy metabolism: metabolic regulator and extracardiac energy storage for hearts.
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Regulation of growth performance and lipid metabolism by dietary n-3 highly unsaturated fatty acids in juvenile grass carp, Ctenopharyngodon idellus. Comp Biochem Physiol B Biochem Mol Biol 2011; 159:49-56. [DOI: 10.1016/j.cbpb.2011.01.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 01/15/2011] [Accepted: 01/30/2011] [Indexed: 11/19/2022]
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Fliesler SJ, Bretillon L. The ins and outs of cholesterol in the vertebrate retina. J Lipid Res 2010; 51:3399-413. [PMID: 20861164 DOI: 10.1194/jlr.r010538] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The vertebrate retina has multiple demands for utilization of cholesterol and must meet those demands either by synthesizing its own supply of cholesterol or by importing cholesterol from extraretinal sources, or both. Unlike the blood-brain barrier, the blood-retina barrier allows uptake of cholesterol from the circulation via a lipoprotein-based/receptor-mediated mechanism. Under normal conditions, cholesterol homeostasis is tightly regulated; also, cholesterol exists in the neural retina overwhelmingly in unesterified form, and sterol intermediates are present in minimal to negligible quantities. However, under certain pathological conditions, either due to an inborn error in cholesterol biosynthesis or as a consequence of exposure to selective inhibitors of enzymes in the cholesterol pathway, the ratio of sterol intermediates to cholesterol in the retina can rise dramatically and persist, in some cases resulting in progressive degeneration that significantly compromises the structure and function of the retina. Although the relative contributions of de novo synthesis versus extraretinal uptake are not yet known, herein we review what is known about these processes and the dynamics of cholesterol in the vertebrate retina and indicate some future avenues of research in this area.
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Affiliation(s)
- Steven J Fliesler
- Research Service, Veterans Administration Western New York Healthcare System, University at Buffalo, The State University of New York, Buffalo, NY, USA.
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Associations of lipoprotein lipase gene polymorphisms with longitudinal plasma lipid trends in young adults: The Coronary Artery Risk Development in Young Adults (CARDIA) study. ACTA ACUST UNITED AC 2010; 3:179-86. [PMID: 20150529 DOI: 10.1161/circgenetics.109.913426] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Genome-wide association studies in European Americans have reported several single-nucleotide polymorphisms (SNPs) in the lipoprotein lipase gene associated with plasma levels of high-density lipoprotein cholesterol (HDL-C) and triglycerides. However, the influences of the lipoprotein lipase SNPs on longitudinal changes of these lipids have not been systematically examined. METHODS AND RESULTS On the basis of data from 2045 African Americans and 2116 European Americans in the Coronary Artery Risk Development in Young Adults study, we investigated cross-sectional and longitudinal associations of lipids with 8 lipoprotein lipase SNPs, including the 2 that have been reported in genome-wide association studies. Plasma levels of HDL-C and triglycerides were measured at 7 examinations during 20 years of follow-up. In European Americans, rs328 (Ser447Stop), rs326, and rs13702 were significantly associated with cross-sectional interindividual variations in triglycerides and HDL-C (P<0.005) and with their longitudinal changes over time (P<0.05). The minor alleles in rs326, rs328, and rs13702 that predispose an individual to lower triglycerides and higher HDL-C levels at young adulthood further slow down the trajectory increase in triglycerides and decrease in HDL-C during 20 years of follow-up. In African Americans, these 3 SNPs were significantly associated with triglycerides, but only rs326 and rs13702 were associated with HDL-C (P<0.008). Rs328 showed a stronger association in European Americans than in African Americans, and adjustment for it did not remove all of the associations for the other SNPs. Longitudinal changes in either trait did not differ significantly by SNP genotypes in African Americans. CONCLUSIONS Our data suggest that aging interacts with LPL gene variants to influence the longitudinal lipid variations, and there is population-related heterogeneity in the longitudinal associations.
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Tissue Distribution of Lipoprotein Lipase (LPL) and Regulation of LPL Gene Expression Induced by Insulin and Glucose in Goose Primary Hepatocytes. J Poult Sci 2010. [DOI: 10.2141/jpsa.009106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Kim MS, Wang F, Puthanveetil P, Kewalramani G, Innis S, Marzban L, Steinberg SF, Webber TD, Kieffer TJ, Abrahani A, Rodrigues B. Cleavage of protein kinase D after acute hypoinsulinemia prevents excessive lipoprotein lipase-mediated cardiac triglyceride accumulation. Diabetes 2009; 58:2464-75. [PMID: 19875622 PMCID: PMC2768155 DOI: 10.2337/db09-0681] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE During hypoinsulinemia, when cardiac glucose utilization is impaired, the heart rapidly adapts to using more fatty acids. One means by which this is achieved is through lipoprotein lipase (LPL). We determined the mechanisms by which the heart regulates LPL after acute hypoinsulinemia. RESEARCH DESIGN AND METHODS We used two different doses of streptozocin (55 [D-55] and 100 [D-100] mg/kg) to induce moderate and severe hypoinsulinemia, respectively, in rats. Isolated cardiomyocytes were also used for transfection or silencing of protein kinase D (PKD) and caspase-3. RESULTS There was substantial increase in LPL in D-55 hearts, an effect that was absent in severely hypoinsulinemic D-100 animals. Measurement of PKD, a key element involved in increasing LPL, revealed that only D-100 hearts showed an increase in proteolysis of PKD, an effect that required activation of caspase-3 together with loss of 14-3-3zeta, a binding protein that protects enzymes against degradation. In vitro, phosphomimetic PKD colocalized with LPL in the trans-golgi. PKD, when mutated to prevent its cleavage by caspase-3 and silencing of caspase-3, was able to increase LPL activity. Using a caspase inhibitor (Z-DEVD) in D-100 animals, we effectively lowered caspase-3 activity, prevented PKD cleavage, and increased LPL vesicle formation and translocation to the vascular lumen. This increase in cardiac luminal LPL was associated with a striking accumulation of cardiac triglyceride in Z-DEVD-treated D-100 rats. CONCLUSIONS After severe hypoinsulinemia, activation of caspase-3 can restrict LPL translocation to the vascular lumen. When caspase-3 is inhibited, this compensatory response is lost, leading to lipid accumulation in the heart.
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Affiliation(s)
- Min Suk Kim
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Fang Wang
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Prasanth Puthanveetil
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Girish Kewalramani
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sheila Innis
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lucy Marzban
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Travis D. Webber
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Timothy J. Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ashraf Abrahani
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding author: B. Rodrigues,
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Kewalramani G, Rodrigues B. AMP-activated protein kinase in the heart: role in cardiac glucose and fatty acid metabolism. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/clp.09.43] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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