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Prater MC, Scheurell AR, Paton CM, Cooper JA. Eight weeks of daily cottonseed oil intake attenuates postprandial angiopoietin-like proteins 3 and 4 responses compared to olive oil in adults with hypercholesterolemia: A secondary analysis of a randomized clinical trial. Nutr Res 2024; 123:88-100. [PMID: 38295507 DOI: 10.1016/j.nutres.2024.01.006] [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: 09/26/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/02/2024]
Abstract
Angiopoietin-like proteins (ANGPTLs) -3, -4, and -8 are regulators of lipid metabolism and have been shown to respond to changes in dietary fats. It is unknown how ANGPTLs respond to cottonseed oil (CSO) and olive oil (OO) consumption in a population with hypercholesterolemia. The purpose of this study was to determine the impact of CSO vs. OO consumption on fasting and postprandial ANGPTL responses in adults with hypercholesterolemia. We hypothesized that CSO would have lower fasting and postprandial ANGPTL responses compared with OO. Forty-two adults with high cholesterol completed a single-blind, randomized trial comparing CSO (n = 21) vs. OO (n = 21) diet enrichment. An 8-week partial outpatient feeding intervention provided ∼60% of the volunteers' total energy expenditure (∼30% of total energy expenditure as CSO or OO). The remaining 40% was not controlled. Fasting blood draws were taken at pre-, mid-, and postintervention visits. Volunteers consumed a high saturated fat meal followed by 5 hours of blood draws pre- and postvisits. Fasting ANGPTL3 had a marginally significant treatment by visit interaction (P = .06) showing an increase from pre- to postintervention in CSO vs. OO (CSO: 385.1 ± 27.7 to 440.3 ± 33.9 ng/mL; OO: 468.2 ± 38.3 to 449.2 ± 49.5 ng/mL). Both postprandial ANGPTL3 (P = .02) and ANGPTL4 (P < .01) had treatment by visit interactions suggesting increases from pre- to postintervention in OO vs. CSO with no differences between groups in ANGPTL8. These data show a worsening (increase) of postprandial ANGPTLs after the OO, but not CSO, intervention. This aligns with previously reported data in which postprandial triglycerides were protected from increases compared with OO. ANGPTLs may mediate protective effects of CSO consumption on lipid control. This trial was registered at clinicaltrials.gov (NCT04397055).
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Affiliation(s)
- M Catherine Prater
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Alex R Scheurell
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Chad M Paton
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA; Department of Food Science and Technology, University of Georgia, Athens, GA, USA
| | - Jamie A Cooper
- Department of Kinesiology, University of Georgia, Athens, GA, USA.
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2
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Sylvers-Davie KL, Bierstedt KC, Schnieders MJ, Davies BSJ. Endothelial lipase variant T111I does not alter inhibition by angiopoietin-like proteins. Sci Rep 2024; 14:4246. [PMID: 38379026 PMCID: PMC10879187 DOI: 10.1038/s41598-024-54705-6] [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: 09/28/2023] [Accepted: 02/15/2024] [Indexed: 02/22/2024] Open
Abstract
High levels of HDL-C are correlated with a decreased risk of cardiovascular disease. HDL-C levels are modulated in part by the secreted phospholipase, endothelial lipase (EL), which hydrolyzes the phospholipids of HDL and decreases circulating HDL-C concentrations. A 584C/T polymorphism in LIPG, the gene which encodes EL, was first identified in individuals with increased HDL levels. This polymorphism results in a T111I point mutation the EL protein. The association between this variant, HDL levels, and the risk of coronary artery disease (CAD) in humans has been extensively studied, but the findings have been inconsistent. In this study, we took a biochemical approach, investigating how the T111I variant affected EL activity, structure, and stability. Moreover, we tested whether the T111I variant altered the inhibition of phospholipase activity by angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4), two known EL inhibitors. We found that neither the stability nor enzymatic activity of EL was altered by the T111I variant. Moreover, we found no difference between wild-type and T111I EL in their ability to be inhibited by ANGPTL proteins. These data suggest that any effect this variant may have on HDL-C levels or cardiovascular disease are not mediated through alterations in these functions.
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Affiliation(s)
- Kelli L Sylvers-Davie
- Department of Biochemistry and Molecular Biology, University of Iowa, 169 Newton Rd., PBDB 3326, Iowa, IA, 52242, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa, IA, 52242, USA
| | - Kaleb C Bierstedt
- Department of Biochemistry and Molecular Biology, University of Iowa, 169 Newton Rd., PBDB 3326, Iowa, IA, 52242, USA
- Department of Biomedical Engineering, University of Iowa, Iowa, IA, 52242, USA
| | - Michael J Schnieders
- Department of Biochemistry and Molecular Biology, University of Iowa, 169 Newton Rd., PBDB 3326, Iowa, IA, 52242, USA
- Department of Biomedical Engineering, University of Iowa, Iowa, IA, 52242, USA
| | - Brandon S J Davies
- Department of Biochemistry and Molecular Biology, University of Iowa, 169 Newton Rd., PBDB 3326, Iowa, IA, 52242, USA.
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa, IA, 52242, USA.
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3
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Sun J, Xie F, Wang J, Luo J, Chen T, Jiang Q, Xi Q, Liu GE, Zhang Y. Integrated meta-omics reveals the regulatory landscape involved in lipid metabolism between pig breeds. MICROBIOME 2024; 12:33. [PMID: 38374121 PMCID: PMC10877772 DOI: 10.1186/s40168-023-01743-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 12/19/2023] [Indexed: 02/21/2024]
Abstract
BACKGROUND Domesticated pigs serve as an ideal animal model for biomedical research and also provide the majority of meat for human consumption in China. Porcine intramuscular fat content associates with human health and diseases and is essential in pork quality. The molecular mechanisms controlling lipid metabolism and intramuscular fat accretion across tissues in pigs, and how these changes in response to pig breeds, remain largely unknown. RESULTS We surveyed the tissue-resident cell types of the porcine jejunum, colon, liver, and longissimus dorsi muscle between Lantang and Landrace breeds by single-cell RNA sequencing. Combining lipidomics and metagenomics approaches, we also characterized gene signatures and determined key discriminating markers of lipid digestibility, absorption, conversion, and deposition across tissues in two pig breeds. In Landrace, lean-meat swine mainly exhibited breed-specific advantages in lipid absorption and oxidation for energy supply in small and large intestinal epitheliums, nascent high-density lipoprotein synthesis for reverse cholesterol transport in enterocytes and hepatocytes, bile acid formation, and secretion for fat emulsification in hepatocytes, as well as intestinal-microbiota gene expression involved in lipid accumulation product. In Lantang, obese-meat swine showed a higher synthesis capacity of chylomicrons responsible for high serum triacylglycerol levels in small intestinal epitheliums, the predominant characteristics of lipid absorption in muscle tissue, and greater intramuscular adipcytogenesis potentials from muscular fibro-adipogenic progenitor subpopulation. CONCLUSIONS The findings enhanced our understanding of the cellular biology of lipid metabolism and opened new avenues to improve animal production and human diseases. Video Abstract.
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Affiliation(s)
- Jiajie Sun
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Fang Xie
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Jing Wang
- Institute of Animal Husbandry and Veterinary Medicine, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China
| | - Junyi Luo
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Ting Chen
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Qingyan Jiang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Qianyun Xi
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China.
| | - George E Liu
- Animal Genomics and Improvement Laboratory, USDA-ARS, BARC-East, Beltsville, MD, 20705, USA.
| | - Yongliang Zhang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China.
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4
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Jiang S, Ren Z, Yang Y, Liu Q, Zhou S, Xiao Y. The GPIHBP1-LPL complex and its role in plasma triglyceride metabolism: Insights into chylomicronemia. Biomed Pharmacother 2023; 169:115874. [PMID: 37951027 DOI: 10.1016/j.biopha.2023.115874] [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: 09/11/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/13/2023] Open
Abstract
GPIHBP1 is a protein found in the endothelial cells of capillaries that is anchored by glycosylphosphatidylinositol and binds to high-density lipoproteins. GPIHBP1 attaches to lipoprotein lipase (LPL), subsequently carrying the enzyme and anchoring it to the capillary lumen. Enabling lipid metabolism is essential for the marginalization of lipoproteins alongside capillaries. Studies underscore the significance of GPIHBP1 in transporting, stabilizing, and aiding in the marginalization of LPL. The intricate interplay between GPIHBP1 and LPL has provided novel insights into chylomicronemia in recent years. Mutations hindering the formation or reducing the efficiency of the GPIHBP1-LPL complex are central to the onset of chylomicronemia. This review delves into the structural nuances of the GPIHBP1-LPL interaction, the consequences of mutations in the complex leading to chylomicronemia, and cutting-edge advancements in chylomicronemia treatment.
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Affiliation(s)
- Shali Jiang
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China; Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Zhuoqun Ren
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China; Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Yutao Yang
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China; Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Qiming Liu
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China
| | - Shenghua Zhou
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China
| | - Yichao Xiao
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China.
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5
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Sylvers-Davie KL, Bierstedt KC, Schnieders MJ, Davies BSJ. Endothelial Lipase Variant, T111I, Does Not Alter Inhibition by Angiopoietin-like Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.18.553740. [PMID: 37693454 PMCID: PMC10491130 DOI: 10.1101/2023.08.18.553740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
High levels of HDL-C are correlated with a decreased risk of cardiovascular disease. HDL-C levels are modulated in part by the secreted phospholipase, endothelial lipase (EL), which hydrolyzes the phospholipids of HDL and decreases circulating HDL-C concentrations. A 584C/T polymorphism in LIPG, the gene which encodes EL, was first identified in individuals with increased HDL levels. This polymorphism results in a T111I point mutation the EL protein. The association between this variant, HDL levels, and the risk of coronary artery disease (CAD) in humans has been extensively studied, but the findings have been inconsistent. In this study, we took a biochemical approach, investigating how the T111I variant affected EL activity, structure, and stability. Moreover, we tested whether the T111I variant altered the inhibition of phospholipase activity by angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4), two known EL inhibitors. We found that neither the stability nor enzymatic activity of EL was altered by the T111I variant. Moreover, we found no difference between wild-type and T111I EL in their ability to be inhibited by ANGPTL proteins. These data suggest that any effect this variant may have on HDL-C levels or cardiovascular disease are not mediated through alterations in these functions.
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Affiliation(s)
- Kelli L. Sylvers-Davie
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242
| | - Kaleb C. Bierstedt
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242
| | - Michael J. Schnieders
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242
| | - Brandon S. J. Davies
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242
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Kumari A, Grønnemose AL, Kristensen KK, Winther AML, Young SG, Jørgensen TJD, Ploug M. Inverse effects of APOC2 and ANGPTL4 on the conformational dynamics of lid-anchoring structures in lipoprotein lipase. Proc Natl Acad Sci U S A 2023; 120:e2221888120. [PMID: 37094117 PMCID: PMC10160976 DOI: 10.1073/pnas.2221888120] [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: 01/03/2023] [Accepted: 03/28/2023] [Indexed: 04/26/2023] Open
Abstract
The lipolytic processing of triglyceride-rich lipoproteins (TRLs) by lipoprotein lipase (LPL) is crucial for the delivery of dietary lipids to the heart, skeletal muscle, and adipose tissue. The processing of TRLs by LPL is regulated in a tissue-specific manner by a complex interplay between activators and inhibitors. Angiopoietin-like protein 4 (ANGPTL4) inhibits LPL by reducing its thermal stability and catalyzing the irreversible unfolding of LPL's α/β-hydrolase domain. We previously mapped the ANGPTL4 binding site on LPL and defined the downstream unfolding events resulting in LPL inactivation. The binding of LPL to glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 protects against LPL unfolding. The binding site on LPL for an activating cofactor, apolipoprotein C2 (APOC2), and the mechanisms by which APOC2 activates LPL have been unclear and controversial. Using hydrogen-deuterium exchange/mass spectrometry, we now show that APOC2's C-terminal α-helix binds to regions of LPL surrounding the catalytic pocket. Remarkably, APOC2's binding site on LPL overlaps with that for ANGPTL4, but their effects on LPL conformation are distinct. In contrast to ANGPTL4, APOC2 increases the thermal stability of LPL and protects it from unfolding. Also, the regions of LPL that anchor the lid are stabilized by APOC2 but destabilized by ANGPTL4, providing a plausible explanation for why APOC2 is an activator of LPL, while ANGPTL4 is an inhibitor. Our studies provide fresh insights into the molecular mechanisms by which APOC2 binds and stabilizes LPL-and properties that we suspect are relevant to the conformational gating of LPL's active site.
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Affiliation(s)
- Anni Kumari
- Finsen Laboratory, Copenhagen University Hospital-Rigshospitalet, DK-2200Copenhagen N, Denmark
- Finsen Laboratory, Biotech Research and Innovation Centre, University of Copenhagen, DK-2200Copenhagen N, Denmark
| | - Anne Louise Grønnemose
- Finsen Laboratory, Copenhagen University Hospital-Rigshospitalet, DK-2200Copenhagen N, Denmark
- Finsen Laboratory, Biotech Research and Innovation Centre, University of Copenhagen, DK-2200Copenhagen N, Denmark
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK–5320Odense, Denmark
| | - Kristian K. Kristensen
- Finsen Laboratory, Copenhagen University Hospital-Rigshospitalet, DK-2200Copenhagen N, Denmark
- Finsen Laboratory, Biotech Research and Innovation Centre, University of Copenhagen, DK-2200Copenhagen N, Denmark
| | - Anne-Marie L. Winther
- Finsen Laboratory, Copenhagen University Hospital-Rigshospitalet, DK-2200Copenhagen N, Denmark
- Finsen Laboratory, Biotech Research and Innovation Centre, University of Copenhagen, DK-2200Copenhagen N, Denmark
| | - 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
| | - Thomas J. D. Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK–5320Odense, Denmark
| | - Michael Ploug
- Finsen Laboratory, Copenhagen University Hospital-Rigshospitalet, DK-2200Copenhagen N, Denmark
- Finsen Laboratory, Biotech Research and Innovation Centre, University of Copenhagen, DK-2200Copenhagen N, Denmark
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7
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Risti R, Gunn KH, Hiis-Hommuk K, Seeba NN, Karimi H, Villo L, Vendelin M, Neher SB, Lõokene A. Combined action of albumin and heparin regulates lipoprotein lipase oligomerization, stability, and ligand interactions. PLoS One 2023; 18:e0283358. [PMID: 37043509 PMCID: PMC10096250 DOI: 10.1371/journal.pone.0283358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/07/2023] [Indexed: 04/13/2023] Open
Abstract
Lipoprotein lipase (LPL), a crucial enzyme in the intravascular hydrolysis of triglyceride-rich lipoproteins, is a potential drug target for the treatment of hypertriglyceridemia. The activity and stability of LPL are influenced by a complex ligand network. Previous studies performed in dilute solutions suggest that LPL can appear in various oligomeric states. However, it was not known how the physiological environment, that is blood plasma, affects the action of LPL. In the current study, we demonstrate that albumin, the major protein component in blood plasma, has a significant impact on LPL stability, oligomerization, and ligand interactions. The effects induced by albumin could not solely be reproduced by the macromolecular crowding effect. Stabilization, isothermal titration calorimetry, and surface plasmon resonance studies revealed that albumin binds to LPL with affinity sufficient to form a complex in both the interstitial space and the capillaries. Negative stain transmission electron microscopy and raster image correlation spectroscopy showed that albumin, like heparin, induced reversible oligomerization of LPL. However, the albumin induced oligomers were structurally different from heparin-induced filament-like LPL oligomers. An intriguing observation was that no oligomers of either type were formed in the simultaneous presence of albumin and heparin. Our data also suggested that the oligomer formation protected LPL from the inactivation by its physiological regulator angiopoietin-like protein 4. The concentration of LPL and its environment could influence whether LPL follows irreversible inactivation and aggregation or reversible LPL oligomer formation, which might affect interactions with various ligands and drugs. In conclusion, the interplay between albumin and heparin could provide a mechanism for ensuring the dissociation of heparan sulfate-bound LPL oligomers into active LPL upon secretion into the interstitial space.
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Affiliation(s)
- Robert Risti
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Kathryn H. Gunn
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kristofer Hiis-Hommuk
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Natjan-Naatan Seeba
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Hamed Karimi
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Ly Villo
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Marko Vendelin
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Saskia B. Neher
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Aivar Lõokene
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
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8
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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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9
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Serum ANGPTL8 and ANGPTL3 as Predictors of Triglyceride Elevation in Adult Women. Metabolites 2022; 12:metabo12060539. [PMID: 35736472 PMCID: PMC9228451 DOI: 10.3390/metabo12060539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 02/01/2023] Open
Abstract
Angiopoietin-like proteins ANGPTL3 and ANGPTL8 have been shown to inhibit lipoprotein lipase, and thus regulate triglyceride level in the circulation. Whether the regulation of lipid metabolism by ANGPTLs is affected by the menopausal status remains unclear. We aimed to assess the relationships between serum ANGPTL3 and ANGPTL8 and atherogenic biomarkers in presumably healthy women during ageing. The study group included 94 women of whom 31 were premenopausal (PRE ≤ 40 years) and 37 were postmenopausal (POST ≥ 52 years). Atherogenic lipid and non-lipid biomarkers and ANGPTLs (ANGPTL3, ANGPTL8) were assayed in serum samples. TG/HDL-C index, non-HDL-cholesterol, remnant cholesterol concentrations, and BMI were calculated. Median levels of ANGPTL3 and concentrations of lipid biomarkers were significantly higher in POST comparing to PRE but ANGPTL8 levels were not different. In PRE, ANGPTL8 levels correlated significantly with TG and TG/HDL-C index while there were no correlations between ANGPTL3 and these biomarkers. In POST both ANGPTLs correlated with TG, sdLDL-C, and TG/HDL-C. ANGPTL8 and sd-LDL-C were the most significant predictors of early triglyceride elevation > 100 mg/dL (1.13 mmol/L) in the whole group and POST whereas the prediction power of ANGPTL3 was negligible in the whole group and non-significant in the subgroups. We demonstrated a significant positive correlation of ANGPTL3 with age category which predisposes to postmenopause. Despite the increase in ANGPTL3 level with ageing the ANGPTL3/ANGPL8 ratio was maintained. In conclusion, ANGPTL8 predicts the early triglyceride elevation better than ANGPTL3, especially in postmenopausal women. The association of ANGPTL3 with triglyceride levels is weaker than ANGPTL8 and depends on menopausal status. We suggest that the choice for the best efficient treatment of dyslipidemia with new inhibitors of angiopoietin-like proteins may depend on the menopausal status.
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10
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Zhao X, Liu H, Pan Y, Liu Y, Zhang F, Ao H, Zhang J, Xing K, Wang C. Identification of Potential Candidate Genes From Co-Expression Module Analysis During Preadipocyte Differentiation in Landrace Pig. Front Genet 2022; 12:753725. [PMID: 35178067 PMCID: PMC8843850 DOI: 10.3389/fgene.2021.753725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/08/2021] [Indexed: 12/12/2022] Open
Abstract
Preadipocyte differentiation plays an important role in lipid deposition and affects fattening efficiency in pigs. In the present study, preadipocytes isolated from the subcutaneous adipose tissue of three Landrace piglets were induced into mature adipocytes in vitro. Gene clusters associated with fat deposition were investigated using RNA sequencing data at four time points during preadipocyte differentiation. Twenty-seven co-expression modules were subsequently constructed using weighted gene co-expression network analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses revealed three modules (blue, magenta, and brown) as being the most critical during preadipocyte differentiation. Based on these data and our previous differentially expressed gene analysis, angiopoietin-like 4 (ANGPTL4) was identified as a key regulator of preadipocyte differentiation and lipid metabolism. After inhibition of ANGPTL4, the expression of adipogenesis-related genes was reduced, except for that of lipoprotein lipase (LPL), which was negatively regulated by ANGPTL4 during preadipocyte differentiation. Our findings provide a new perspective to understand the mechanism of fat deposition.
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Affiliation(s)
- Xitong Zhao
- Beijing Shunxin Agriculture Co., Ltd., Beijing, China.,China Agricultural University, Beijing, China
| | - Huatao Liu
- China Agricultural University, Beijing, China
| | - Yongjie Pan
- Beijing Shunxin Agriculture Co., Ltd., Beijing, China
| | - Yibing Liu
- China Agricultural University, Beijing, China
| | | | - Hong Ao
- Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jibin Zhang
- City of Hope National Medical Center, Duarte, CA, United States
| | - Kai Xing
- Beijing University of Agriculture, Beijing, China
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11
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Paragh G, Németh Á, Harangi M, Banach M, Fülöp P. Causes, clinical findings and therapeutic options in chylomicronemia syndrome, a special form of hypertriglyceridemia. Lipids Health Dis 2022; 21:21. [PMID: 35144640 PMCID: PMC8832680 DOI: 10.1186/s12944-022-01631-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/30/2022] [Indexed: 02/07/2023] Open
Abstract
The prevalence of hypertriglyceridemia has been increasing worldwide. Attention is drawn to the fact that the frequency of a special hypertriglyceridemia entity, named chylomicronemia syndrome, is variable among its different forms. The monogenic form, termed familial chylomicronemia syndrome, is rare, occuring in 1 in every 1 million persons. On the other hand, the prevalence of the polygenic form of chylomicronemia syndrome is around 1:600. On the basis of the genetical alterations, other factors, such as obesity, alcohol consumption, uncontrolled diabetes mellitus and certain drugs may significantly contribute to the development of the multifactorial form. In this review, we aimed to highlight the recent findings about the clinical and laboratory features, differential diagnosis, as well as the epidemiology of the monogenic and polygenic forms of chylomicronemias. Regarding the therapy, differentiation between the two types of the chylomicronemia syndrome is essential, as well. Thus, proper treatment options of chylomicronemia and hypertriglyceridemia will be also summarized, emphasizing the newest therapeutic approaches, as novel agents may offer solution for the effective treatment of these conditions.
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Affiliation(s)
- György Paragh
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary.
| | - Ákos Németh
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Mariann Harangi
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Maciej Banach
- Department of Hypertension, WAM University Hospital in Lodz, Medical University of Lodz, Lodz, Poland.,Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland
| | - Péter Fülöp
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
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12
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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: 42] [Impact Index Per Article: 21.0] [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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13
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Lipoprotein size is a main determinant for the rate of hydrolysis by exogenous lipoprotein lipase in human plasma. J Lipid Res 2021; 63:100144. [PMID: 34710432 PMCID: PMC8953621 DOI: 10.1016/j.jlr.2021.100144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/19/2022] Open
Abstract
Lipoprotein lipase (LPL) is a key player in plasma triglyceride metabolism. Consequently, LPL is regulated by several proteins during synthesis, folding, secretion, and transport to its site of action at the luminal side of capillaries, as well as during the catalytic reaction. Some proteins are well known, while others have been identified but are still not fully understood. We set out to study the effects of the natural variations in the plasma levels of all known LPL regulators on the activity of purified LPL added to samples of fasted plasma taken from 117 individuals. The enzymatic activity was measured at 25° C using isothermal titration calorimetry. This method allows quantification of the ability of an added fixed amount of exogenous LPL to hydrolyze triglyceride-rich lipoproteins in plasma samples by measuring the heat produced. Our results indicate that, under the conditions used, the normal variation in the endogenous levels of apolipoprotein C1, C2 and C3, or the levels of angiopoietin-like proteins 3, 4, and 8 in the fasted plasma samples had no significant effect on the recorded activity of the added LPL. Instead, the key determinant for the LPL activity was a lipid signature strongly correlated to the average size of the VLDL particles. The signature involved several lipoprotein and plasma lipid parameters, but also apolipoprotein A5 levels. While the measurements cannot fully represent the action of LPL when attached to the capillary wall, our study provides knowledge on the interindividual variation of LPL lipolysis rates in human plasma.
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14
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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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15
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Sylvers-Davie KL, Segura-Roman A, Salvi AM, Schache KJ, Davies BSJ. Angiopoietin-like 3 inhibition of endothelial lipase is not modulated by angiopoietin-like 8. J Lipid Res 2021; 62:100112. [PMID: 34461133 PMCID: PMC8456055 DOI: 10.1016/j.jlr.2021.100112] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/10/2021] [Accepted: 08/24/2021] [Indexed: 01/02/2023] Open
Abstract
High plasma triglyceride (TG) levels and low HDL-C levels are risk factors for atherosclerosis and cardiovascular disease. Both plasma TG and HDL-C levels are regulated in part by the circulating inhibitor, angiopoietin-like 3 (ANGPTL3). ANGPTL3 inhibits the phospholipase, endothelial lipase (EL), which hydrolyzes the phospholipids of HDL, thus decreasing plasma HDL levels. ANGPTL3 also inhibits LPL, the lipase primarily responsible for the clearance of TGs from the circulation. Previous studies have shown that ANGPTL3 requires complex formation with the related ANGPTL protein, angiopoietin-like 8 (ANGPTL8), to efficiently inhibit LPL, but the role of ANGPTL8 in EL inhibition is not known. In this study, we characterized inhibition and binding of EL by ANGPTL3 and investigated the role of ANGPTL8 in EL inhibition. We found that inhibition of EL by ANGPTL3 was dose dependent and temperature dependent. Interestingly, this inhibition was diminished when EL was bound to endothelial cells or in the presence of heparin. Unlike previous findings with LPL, we found that ANGPTL8 did not significantly alter the binding or the inhibition of EL by ANGPTL3. In addition, we found that a common ANGPTL8 variant, which encodes an R59W mutation, altered the ability of ANGPTL3 to bind and inhibit LPL but not EL. Together, our data indicate that ANGPTL8 is not necessary for EL inhibition. We conclude that ANGPTL8 is specific for the regulation of TG-rich lipoproteins through the LPL pathway and that therapeutically targeting ANGPTL8 for the treatment of hypertriglyceridemia or cardiovascular disease may have different outcomes than targeting ANGPTL3.
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Affiliation(s)
- Kelli L Sylvers-Davie
- Department of Biochemistry and Molecular Biology, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, IA, USA
| | - Ashley Segura-Roman
- Department of Biochemistry and Molecular Biology, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, IA, USA
| | - Alicia M Salvi
- Department of Biochemistry and Molecular Biology, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, IA, USA
| | - Kylie J Schache
- Department of Biochemistry and Molecular Biology, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, IA, USA
| | - Brandon S J Davies
- Department of Biochemistry and Molecular Biology, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, IA, USA.
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16
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Kristensen KK, Leth-Espensen KZ, Kumari A, Grønnemose AL, Lund-Winther AM, Young SG, Ploug M. GPIHBP1 and ANGPTL4 Utilize Protein Disorder to Orchestrate Order in Plasma Triglyceride Metabolism and Regulate Compartmentalization of LPL Activity. Front Cell Dev Biol 2021; 9:702508. [PMID: 34336854 PMCID: PMC8319833 DOI: 10.3389/fcell.2021.702508] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022] Open
Abstract
Intravascular processing of triglyceride-rich lipoproteins (TRLs) is crucial for delivery of dietary lipids fueling energy metabolism in heart and skeletal muscle and for storage in white adipose tissue. During the last decade, mechanisms underlying focal lipolytic processing of TRLs along the luminal surface of capillaries have been clarified by fresh insights into the functions of lipoprotein lipase (LPL); LPL's dedicated transporter protein, glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1); and its endogenous inhibitors, angiopoietin-like (ANGPTL) proteins 3, 4, and 8. Key discoveries in LPL biology include solving the crystal structure of LPL, showing LPL is catalytically active as a monomer rather than as a homodimer, and that the borderline stability of LPL's hydrolase domain is crucial for the regulation of LPL activity. Another key discovery was understanding how ANGPTL4 regulates LPL activity. The binding of ANGPTL4 to LPL sequences adjacent to the catalytic cavity triggers cooperative and sequential unfolding of LPL's hydrolase domain resulting in irreversible collapse of the catalytic cavity and loss of LPL activity. Recent studies have highlighted the importance of the ANGPTL3-ANGPTL8 complex for endocrine regulation of LPL activity in oxidative organs (e.g., heart, skeletal muscle, brown adipose tissue), but the molecular mechanisms have not been fully defined. New insights have also been gained into LPL-GPIHBP1 interactions and how GPIHBP1 moves LPL to its site of action in the capillary lumen. GPIHBP1 is an atypical member of the LU (Ly6/uPAR) domain protein superfamily, containing an intrinsically disordered and highly acidic N-terminal extension and a disulfide bond-rich three-fingered LU domain. Both the disordered acidic domain and the folded LU domain are crucial for the stability and transport of LPL, and for modulating its susceptibility to ANGPTL4-mediated unfolding. This review focuses on recent advances in the biology and biochemistry of crucial proteins for intravascular lipolysis.
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Affiliation(s)
- Kristian Kølby Kristensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Katrine Zinck Leth-Espensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Anni Kumari
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Anne Louise Grønnemose
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Anne-Marie Lund-Winther
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Stephen G Young
- Departments of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
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17
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The Importance of Lipoprotein Lipase Regulation in Atherosclerosis. Biomedicines 2021; 9:biomedicines9070782. [PMID: 34356847 PMCID: PMC8301479 DOI: 10.3390/biomedicines9070782] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/02/2021] [Accepted: 07/04/2021] [Indexed: 02/07/2023] Open
Abstract
Lipoprotein lipase (LPL) plays a major role in the lipid homeostasis mainly by mediating the intravascular lipolysis of triglyceride rich lipoproteins. Impaired LPL activity leads to the accumulation of chylomicrons and very low-density lipoproteins (VLDL) in plasma, resulting in hypertriglyceridemia. While low-density lipoprotein cholesterol (LDL-C) is recognized as a primary risk factor for atherosclerosis, hypertriglyceridemia has been shown to be an independent risk factor for cardiovascular disease (CVD) and a residual risk factor in atherosclerosis development. In this review, we focus on the lipolysis machinery and discuss the potential role of triglycerides, remnant particles, and lipolysis mediators in the onset and progression of atherosclerotic cardiovascular disease (ASCVD). This review details a number of important factors involved in the maturation and transportation of LPL to the capillaries, where the triglycerides are hydrolyzed, generating remnant lipoproteins. Moreover, LPL and other factors involved in intravascular lipolysis are also reported to impact the clearance of remnant lipoproteins from plasma and promote lipoprotein retention in capillaries. Apolipoproteins (Apo) and angiopoietin-like proteins (ANGPTLs) play a crucial role in regulating LPL activity and recent insights into LPL regulation may elucidate new pharmacological means to address the challenge of hypertriglyceridemia in atherosclerosis development.
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18
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The intrinsic instability of the hydrolase domain of lipoprotein lipase facilitates its inactivation by ANGPTL4-catalyzed unfolding. Proc Natl Acad Sci U S A 2021; 118:2026650118. [PMID: 33723082 DOI: 10.1073/pnas.2026650118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The complex between lipoprotein lipase (LPL) and its endothelial receptor (GPIHBP1) is responsible for the lipolytic processing of triglyceride-rich lipoproteins (TRLs) along the capillary lumen, a physiologic process that releases lipid nutrients for vital organs such as heart and skeletal muscle. LPL activity is regulated in a tissue-specific manner by endogenous inhibitors (angiopoietin-like [ANGPTL] proteins 3, 4, and 8), but the molecular mechanisms are incompletely understood. ANGPTL4 catalyzes the inactivation of LPL monomers by triggering the irreversible unfolding of LPL's α/β-hydrolase domain. Here, we show that this unfolding is initiated by the binding of ANGPTL4 to sequences near LPL's catalytic site, including β2, β3-α3, and the lid. Using pulse-labeling hydrogen‒deuterium exchange mass spectrometry, we found that ANGPTL4 binding initiates conformational changes that are nucleated on β3-α3 and progress to β5 and β4-α4, ultimately leading to the irreversible unfolding of regions that form LPL's catalytic pocket. LPL unfolding is context dependent and varies with the thermal stability of LPL's α/β-hydrolase domain (T m of 34.8 °C). GPIHBP1 binding dramatically increases LPL stability (T m of 57.6 °C), while ANGPTL4 lowers the onset of LPL unfolding by ∼20 °C, both for LPL and LPL•GPIHBP1 complexes. These observations explain why the binding of GPIHBP1 to LPL retards the kinetics of ANGPTL4-mediated LPL inactivation at 37 °C but does not fully suppress inactivation. The allosteric mechanism by which ANGPTL4 catalyzes the irreversible unfolding and inactivation of LPL is an unprecedented pathway for regulating intravascular lipid metabolism.
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19
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Gunn KH, Gutgsell AR, Xu Y, Johnson CV, Liu J, Neher SB. Comparison of angiopoietin-like protein 3 and 4 reveals structural and mechanistic similarities. J Biol Chem 2021; 296:100312. [PMID: 33482195 PMCID: PMC7949051 DOI: 10.1016/j.jbc.2021.100312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/07/2021] [Accepted: 01/15/2021] [Indexed: 12/17/2022] Open
Abstract
Elevated plasma triglycerides are a risk factor for coronary artery disease, which is the leading cause of death worldwide. Lipoprotein lipase (LPL) reduces triglycerides in the blood by hydrolyzing them from triglyceride-rich lipoproteins to release free fatty acids. LPL activity is regulated in a nutritionally responsive manner by macromolecular inhibitors including angiopoietin-like proteins 3 and 4 (ANGPTL3 and ANGPTL4). However, the mechanism by which ANGPTL3 inhibits LPL is unclear, in part due to challenges in obtaining pure protein for study. We used a new purification protocol for the N-terminal domain of ANGPTL3, removing a DNA contaminant, and found DNA-free ANGPTL3 showed enhanced inhibition of LPL. Structural analysis showed that ANGPTL3 formed elongated, flexible trimers and hexamers that did not interconvert. ANGPTL4 formed only elongated flexible trimers. We compared the inhibition of ANGPTL3 and ANGPTL4 using human very-low-density lipoproteins as a substrate and found both were noncompetitive inhibitors. The inhibition constants for the trimeric ANGPTL3 (7.5 ± 0.7 nM) and ANGPTL4 (3.6 ± 1.0 nM) were only 2-fold different. Heparin has previously been reported to interfere with ANGPTL3 binding to LPL, so we questioned if the negatively charged heparin was acting in a similar fashion to the DNA contaminant. We found that ANGPTL3 inhibition is abolished by binding to low-molecular-weight heparin, whereas ANGPTL4 inhibition is not. Our data show new similarities and differences in how ANGPTL3 and ANGPTL4 regulate LPL and opens new avenues of investigating the effect of heparin on LPL inhibition by ANGPTL3.
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Affiliation(s)
- Kathryn H Gunn
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Aspen R Gutgsell
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Yongmei Xu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Caitlin V Johnson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jian Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Saskia B Neher
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA.
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20
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Abstract
PURPOSE OF REVIEW Since the first discovery of Angiopoetin-like 4 (ANGPTL4) in 2000, the involvement of ANGPTL4 in different aspects of lipid metabolism and vascular biology has emerged as an important research field. In this review, we summarize the fundamental roles of ANGPTL4 in regulating metabolic and nonmetabolic functions and their implication in lipid metabolism and with several aspects of vascular function and dysfunction. RECENT FINDINGS ANGPTL4 is a secreted glycoprotein with a physiological role in lipid metabolism and a predominant expression in adipose tissue and liver. ANGPTL4 inhibits the activity of lipoprotein lipase and thereby promotes an increase in circulating triglyceride levels. Therefore, ANGPTL4 has been highly scrutinized as a potential therapeutic target. Further involvement of ANGPTL4 has been shown to occur in tumorigenesis, angiogenesis, vascular permeability and stem cell regulation, which opens new opportunities of using ANGPTL4 as potential therapeutic targets for other pathophysiological conditions. SUMMARY Further determination of ANGPTL4 regulatory circuits and defining specific molecular events that mediate its biological effects remain key to future ANGPTL4-based therapeutic applications in different disease settings. Many new and unanticipated roles of ANGPTL4 in the control of cell-specific functions will assist clinicians and researchers in developing potential therapeutic applications.
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21
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Barchetta I, Chiappetta C, Ceccarelli V, Cimini FA, Bertoccini L, Gaggini M, Cristofano CD, Silecchia G, Lenzi A, Leonetti F, Baroni MG, Gastaldelli A, Cavallo MG. Angiopoietin-Like Protein 4 Overexpression in Visceral Adipose Tissue from Obese Subjects with Impaired Glucose Metabolism and Relationship with Lipoprotein Lipase. Int J Mol Sci 2020; 21:ijms21197197. [PMID: 33003532 PMCID: PMC7582588 DOI: 10.3390/ijms21197197] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 09/26/2020] [Indexed: 12/11/2022] Open
Abstract
Angiopoietin-like protein 4 (ANGPTL4) regulates lipid partitioning by inhibiting circulating and tissue lipoprotein lipase (LPL); ANGPTL4 loss-of-function variants improve insulin sensitivity and reduce type 2 diabetes (T2D) risk with mechanisms partially unknown. This study was designed to explore metabolic implications of differential ANGPTL4 and LPL expression in human adipose tissue (AT). We recruited eighty-eight obese individuals, with and without abnormal glucose metabolism (AGM), undergoing bariatric surgery; visceral AT (VAT) fragments were obtained intra-operatively and analyzed by immunohistochemistry and mRNA by rt-PCR. Data on hepatic ANGPTL4 mRNA were available for 40 participants. VAT ANGPTL4 expression was higher in AGM individuals than in those with normal glucose tolerance (NGT) and associated with VAT inflammation, insulin resistance, and presence of adipocyte size heterogeneity. Increased ANGPTL4 was associated with AGM with OR = 5.1 (95% C.I.: 1.2–23; p = 0.02) and AUROC = 0.76 (95% C.I.: 1.2–23; p < 0.001). High LPL was associated with the detection of homogeneous adipocyte size, reduced microvessel density, and higher HIF-1α levels and inversely correlated to blood transaminases. In conclusion, in obese individuals, VAT ANGPTL4 levels are increased in the presence of local inflammation and AGM. Conversely, higher LPL expression describes a condition of increased lipid storage in adipocytes, which may serve as a protective mechanism against ectopic fat accumulation and related metabolic disease in obesity.
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Affiliation(s)
- Ilaria Barchetta
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy; (I.B.); (V.C.); (F.A.C.); (L.B.); (A.L.)
| | - Caterina Chiappetta
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University, 04100 Latina, Italy; (C.C.); (C.D.C.); (G.S.); (F.L.)
| | - Valentina Ceccarelli
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy; (I.B.); (V.C.); (F.A.C.); (L.B.); (A.L.)
| | - Flavia Agata Cimini
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy; (I.B.); (V.C.); (F.A.C.); (L.B.); (A.L.)
| | - Laura Bertoccini
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy; (I.B.); (V.C.); (F.A.C.); (L.B.); (A.L.)
| | - Melania Gaggini
- Cardiometabolic Risk Unit, Institute of Clinical Physiology, CNR, 56100 Pisa, Italy;
| | - Claudio Di Cristofano
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University, 04100 Latina, Italy; (C.C.); (C.D.C.); (G.S.); (F.L.)
| | - Gianfranco Silecchia
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University, 04100 Latina, Italy; (C.C.); (C.D.C.); (G.S.); (F.L.)
| | - Andrea Lenzi
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy; (I.B.); (V.C.); (F.A.C.); (L.B.); (A.L.)
| | - Frida Leonetti
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University, 04100 Latina, Italy; (C.C.); (C.D.C.); (G.S.); (F.L.)
| | - Marco Giorgio Baroni
- Department of Clinical Medicine, Public Health, Life and Environmental Sciences (MeSVA) University of L’Aquila, 67100 Coppito (AQ) Italy;
- IRCCS Neuromed, 86077 Pozzilli (Is), Italy
| | - Amalia Gastaldelli
- Cardiometabolic Risk Unit, Institute of Clinical Physiology, CNR, 56100 Pisa, Italy;
- Correspondence: (A.G.); (M.G.C.); Tel.: +39-(0)6-4997-4692 (M.G.C.)
| | - Maria Gisella Cavallo
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy; (I.B.); (V.C.); (F.A.C.); (L.B.); (A.L.)
- Correspondence: (A.G.); (M.G.C.); Tel.: +39-(0)6-4997-4692 (M.G.C.)
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22
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Yang J, Li X, Xu D. Research Progress on the Involvement of ANGPTL4 and Loss-of-Function Variants in Lipid Metabolism and Coronary Heart Disease: Is the "Prime Time" of ANGPTL4-Targeted Therapy for Coronary Heart Disease Approaching? Cardiovasc Drugs Ther 2020; 35:467-477. [PMID: 32500296 DOI: 10.1007/s10557-020-07001-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Multiple genetic studies have confirmed the definitive link among the loss-of-function variants of angiogenin-like protein 4 (ANGPTL4), significantly decreased plasma triglyceride (TG) levels, and reduced risk of coronary heart disease (CHD). The potential therapeutic effect of ANGPTL4 on dyslipidemia and CHD has been widely studied. OBJECTIVE This review provides a detailed introduction to the research progress on the involvement of ANGPTL4 in lipid metabolism and atherosclerosis and evaluates the efficacy and safety of ANGPTL4 as a therapeutic target for CHD. RELEVANT FINDINGS By inhibiting lipoprotein lipase (LPL) activity, ANGPTL4 plays a vital role in the regulation of lipid metabolism and energy balance. However, the role of ANGPTL4 in regulating lipid metabolism is tissue-specific. ANGPTL4 acts as a locally released LPL inhibitor in the heart, skeletal muscle and small intestine, while ANGPTL4 derived from liver and adipose tissue mainly acts as an endocrine factor that regulates systemic lipid metabolism. As a multifunctional protein, ANGPTL4 also inhibits the formation of foam cells in macrophages, exerting an anti-atherogenic role. The function of ANGPTL4 in endothelial cells is still uncertain. The safety of ANGPTL4 monoclonal antibodies requires further evaluation due to their potential adverse effects. CONCLUSION The biological characteristics of ANGPTL4 are much more complex than those demonstrated by genetic studies. Future studies must elucidate how to effectively reduce the risk of CHD while avoiding potential atherogenic effects and other complications before the "prime time" of ANGPTL4-targeted therapy arrives.
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Affiliation(s)
- Jingmin Yang
- Department of Cardiology, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410000, Hunan, China
| | - Xiao Li
- Department of Cardiology, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410000, Hunan, China
| | - Danyan Xu
- Department of Cardiology, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410000, Hunan, China.
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Chen YQ, Pottanat TG, Siegel RW, Ehsani M, Qian YW, Zhen EY, Regmi A, Roell WC, Guo H, Luo MJ, Gimeno RE, Van't Hooft F, Konrad RJ. Angiopoietin-like protein 8 differentially regulates ANGPTL3 and ANGPTL4 during postprandial partitioning of fatty acids. J Lipid Res 2020; 61:1203-1220. [PMID: 32487544 PMCID: PMC7397750 DOI: 10.1194/jlr.ra120000781] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/09/2020] [Indexed: 12/11/2022] Open
Abstract
Angiopoietin-like protein (ANGPTL)8 has been implicated in metabolic syndrome and reported to regulate adipose FA uptake through unknown mechanisms. Here, we studied how complex formation of ANGPTL8 with ANGPTL3 or ANGPTL4 varies with feeding to regulate LPL. In human serum, ANGPTL3/8 and ANGPTL4/8 complexes both increased postprandially, correlated negatively with HDL, and correlated positively with all other metabolic syndrome markers. ANGPTL3/8 also correlated positively with LDL-C and blocked LPL-facilitated hepatocyte VLDL-C uptake. LPL-inhibitory activity of ANGPTL3/8 was >100-fold more potent than that of ANGPTL3, and LPL-inhibitory activity of ANGPTL4/8 was >100-fold less potent than that of ANGPTL4. Quantitative analyses of inhibitory activities and competition experiments among the complexes suggested a model in which localized ANGPTL4/8 blocks the LPL-inhibitory activity of both circulating ANGPTL3/8 and localized ANGPTL4, allowing lipid sequestration into fat rather than muscle during the fed state. Supporting this model, insulin increased ANGPTL3/8 secretion from hepatocytes and ANGPTL4/8 secretion from adipocytes. These results suggest that low ANGPTL8 levels during fasting enable ANGPTL4-mediated LPL inhibition in fat tissue to minimize adipose FA uptake. During feeding, increased ANGPTL8 increases ANGPTL3 inhibition of LPL in muscle via circulating ANGPTL3/8, while decreasing ANGPTL4 inhibition of LPL in adipose tissue through localized ANGPTL4/8, thereby increasing FA uptake into adipose tissue. Excessive caloric intake may shift this system toward the latter conditions, possibly predisposing to metabolic syndrome.
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Affiliation(s)
- Yan Q Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Thomas G Pottanat
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Robert W Siegel
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Mariam Ehsani
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Yue-Wei Qian
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Eugene Y Zhen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Ajit Regmi
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - William C Roell
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Haihong Guo
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - M Jane Luo
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Ruth E Gimeno
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Ferdinand Van't Hooft
- Division of Cardiovascular Medicine, Department of Medicine Solna, Karolinska Institutet Karolinska University Hospital Solna, Stockholm, Sweden
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
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Unfolding of monomeric lipoprotein lipase by ANGPTL4: Insight into the regulation of plasma triglyceride metabolism. Proc Natl Acad Sci U S A 2020; 117:4337-4346. [PMID: 32034094 DOI: 10.1073/pnas.1920202117] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The binding of lipoprotein lipase (LPL) to GPIHBP1 focuses the intravascular hydrolysis of triglyceride-rich lipoproteins on the surface of capillary endothelial cells. This process provides essential lipid nutrients for vital tissues (e.g., heart, skeletal muscle, and adipose tissue). Deficiencies in either LPL or GPIHBP1 impair triglyceride hydrolysis, resulting in severe hypertriglyceridemia. The activity of LPL in tissues is regulated by angiopoietin-like proteins 3, 4, and 8 (ANGPTL). Dogma has held that these ANGPTLs inactivate LPL by converting LPL homodimers into monomers, rendering them highly susceptible to spontaneous unfolding and loss of enzymatic activity. Here, we show that binding of an LPL-specific monoclonal antibody (5D2) to the tryptophan-rich lipid-binding loop in the carboxyl terminus of LPL prevents homodimer formation and forces LPL into a monomeric state. Of note, 5D2-bound LPL monomers are as stable as LPL homodimers (i.e., they are not more prone to unfolding), but they remain highly susceptible to ANGPTL4-catalyzed unfolding and inactivation. Binding of GPIHBP1 to LPL alone or to 5D2-bound LPL counteracts ANGPTL4-mediated unfolding of LPL. In conclusion, ANGPTL4-mediated inactivation of LPL, accomplished by catalyzing the unfolding of LPL, does not require the conversion of LPL homodimers into monomers. Thus, our findings necessitate changes to long-standing dogma on mechanisms for LPL inactivation by ANGPTL proteins. At the same time, our findings align well with insights into LPL function from the recent crystal structure of the LPL•GPIHBP1 complex.
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Abstract
Endothelial cells line all blood vessels in vertebrates. These cells contribute to whole-body nutrient distribution in a variety of ways, including regulation of local blood flow, regulation of trans-endothelial nutrient transport, and paracrine effects. Obesity elicits dramatic whole-body nutrient redistribution, in particular of fat. We briefly review here recent progress on understanding endothelial fat transport; the impact of obesity on the endothelium; and, conversely, how endothelial function can modulate obesity.
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Affiliation(s)
- Nora Yucel
- Perelman School of Medicine, University of Pennsylvania
| | - Zolt Arany
- Perelman School of Medicine, University of Pennsylvania
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26
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Ruscica M, Zimetti F, Adorni MP, Sirtori CR, Lupo MG, Ferri N. Pharmacological aspects of ANGPTL3 and ANGPTL4 inhibitors: New therapeutic approaches for the treatment of atherogenic dyslipidemia. Pharmacol Res 2020; 153:104653. [PMID: 31931117 DOI: 10.1016/j.phrs.2020.104653] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/24/2022]
Abstract
Among the determinants of atherosclerotic cardiovascular disease (ASCVD), genetic and experimental evidence has provided data on a major role of angiopoietin-like proteins 3 and 4 (ANGPTL3 and ANGPTL4) in regulating the activity of lipoprotein lipase (LPL), antagonizing the hydrolysis of triglycerides (TG). Indeed, beyond low-density lipoprotein cholesterol (LDL-C), ASCVD risk is also dependent on a cluster of metabolic abnormalities characterized by elevated fasting and post-prandial levels of TG-rich lipoproteins and their remnants. In a head-to-head comparison between murine models for ANGPTL3 and ANGPTL4, the former was found to be a better pharmacological target for the treatment of hypertriglyceridemia. In humans, loss-of-function mutations of ANGPTL3 are associated with a marked reduction of plasma levels of VLDL, low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Carriers of loss-of-function mutations of ANGPTL4 show instead lower TG-rich lipoproteins and a modest but significant increase of HDL. The relevance of ANGPTL3 and ANGPTL4 as new therapeutic targets is proven by the development of monoclonal antibodies or antisense oligonucleotides. Studies in animal models, including non-human primates, have demonstrated that short-term treatment with monoclonal antibodies against ANGPTL3 and ANGPTL4 induces activation of LPL and a marked reduction of plasma TG-rich-lipoproteins, apparently without any major side effects. Inhibition of both targets also partially reduces LDL-C, independent of the LDL receptor. Similar evidence has been observed with the antisense oligonucleotide ANGPTL3-LRX. The genetic studies have paved the way for the development of new ANGPTL3 and 4 antagonists for the treatment of atherogenic dyslipidemias. Conclusive data of phase 2 and 3 clinical trials are still needed in order to define their safety and efficacy profile.
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Affiliation(s)
- Massimiliano Ruscica
- Dipartimento di Science Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy.
| | - Francesca Zimetti
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Maria Pia Adorni
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Cesare R Sirtori
- Dyslipidemia Center, A.S.S.T. Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Maria Giovanna Lupo
- Dipartimento di Scienze del Farmaco, Università degli Studi di Padova, Padua, Italy
| | - Nicola Ferri
- Dipartimento di Scienze del Farmaco, Università degli Studi di Padova, Padua, Italy
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Li J, Li L, Guo D, Li S, Zeng Y, Liu C, Fu R, Huang M, Xie W. Triglyceride metabolism and angiopoietin-like proteins in lipoprotein lipase regulation. Clin Chim Acta 2020; 503:19-34. [PMID: 31923423 DOI: 10.1016/j.cca.2019.12.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/31/2019] [Accepted: 12/31/2019] [Indexed: 12/21/2022]
Abstract
Hypertriglyceridemia is a risk factor for a series of diseases, such as cardiovascular disease (CVD), diabetes and nonalcoholic fatty liver disease (NAFLD). Angiopoietin-like proteins (ANGPTLs) family, especially ANGPTL3, ANGPTL4 and ANGPTL8, which regulate lipoprotein lipase (LPL) activity, play pivotal roles in triglyceride (TG) metabolism and related diseases/complications. There are many transcriptional and post-transcriptional factors that participate in physiological and pathological regulation of ANGPTLs to affect triglyceride metabolism. This review is intended to focus on the similarity and difference in the expression, structural features, regulation profile of the three ANGPTLs and inhibitory models for LPL. Description of the regulatory factors of ANGPTLs and the properties in regulating the lipid metabolism involved in the underlying mechanisms in pathological effects on diseases will provide potential therapeutic approaches for the treatment of dyslipidemia related diseases.
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Affiliation(s)
- Jing Li
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China; 2016 Class of Clinical Medicine, University of South China, Hengyang 421001, Hunan, China
| | - Liang Li
- Department of Pathophysiology, University of South China, Hengyang 421001, Hunan, China
| | - DongMing Guo
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China
| | - SuYun Li
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China
| | - YuXin Zeng
- 2018 Class of Excellent Doctor, University of South China, Hengyang 421001, Hunan, China
| | - ChuHao Liu
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China; 2016 Class of Clinical Medicine, University of South China, Hengyang 421001, Hunan, China
| | - Ru Fu
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China; 2016 Class of Clinical Medicine, University of South China, Hengyang 421001, Hunan, China
| | - MengQian Huang
- 2015 Class of Clinical Medicine, Fuxing Hospital, Capital Medical University, Beijing 100038, China.
| | - Wei Xie
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China.
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Nauli AM, Matin S. Why Do Men Accumulate Abdominal Visceral Fat? Front Physiol 2019; 10:1486. [PMID: 31866877 PMCID: PMC6906176 DOI: 10.3389/fphys.2019.01486] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 11/21/2019] [Indexed: 12/18/2022] Open
Abstract
Men have a higher tendency to accumulate abdominal visceral fat compared to pre-menopausal women. The accumulation of abdominal visceral fat in men, which is a strong independent predictor of mortality, is mainly due to the higher dietary fat uptake by their abdominal visceral fat. Since dietary fat is absorbed by the enterocytes and transported to the circulation in the forms of chylomicrons and very low density lipoproteins (VLDLs), it is crucial to understand how these lipoproteins are different between men and women. The chylomicrons in men are generally bigger in size and more in quantity than those in women. During the postprandial state, these chylomicrons congest the lamina propria and the low-pressure lymphatics. In this paper, we propose that this congestion predisposes the chylomicron triglycerides to hydrolysis by lipoprotein lipase (LPL). The liberated fatty acids are then stored by the nearby abdominal visceral adipocytes, leading to the accumulation of abdominal visceral fat. These mechanisms perhaps explain why men, through their bigger and higher production of chylomicrons, are more likely to accumulate abdominal visceral fat than pre-menopausal women. This accumulation eventually leads to belly enlargement, which confers men their apple-shaped body.
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Affiliation(s)
- Andromeda M Nauli
- Department of Pharmaceutical Sciences, College of Pharmacy, Marshall B. Ketchum University, Fullerton, CA, United States
| | - Sahar Matin
- College of Pharmacy, Marshall B. Ketchum University, Fullerton, CA, United States
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29
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Effect of mountain ultra-marathon running on plasma angiopoietin-like protein 4 and lipid profile in healthy trained men. Eur J Appl Physiol 2019; 120:117-125. [PMID: 31707478 PMCID: PMC6969869 DOI: 10.1007/s00421-019-04256-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/31/2019] [Indexed: 02/06/2023]
Abstract
Purpose Angiopoietin-like protein 4 (ANGPTL4) regulates lipid metabolism by inhibiting lipoprotein lipase activity and stimulating lipolysis in adipose tissue. The aim of this study was to find out whether the mountain ultra-marathon running influences plasma ANGPTL4 and whether it is related to plasma lipid changes. Methods Ten healthy men (age 31 ± 1.1 years) completed a 100-km ultra-marathon running. Plasma ANGPTL4, free fatty acids (FFA), triacylglycerols (TG), glycerol (Gly), total cholesterol (TC), low (LDL-C) and high (HDL-C) density lipoprotein-cholesterol were determined before, immediately after the run and after 90 min of recovery. Results Plasma ANGPTL4 increased during exercise from 68.0 ± 16.5 to 101.2 ± 18.1 ng/ml (p < 0.001). This was accompanied by significant increases in plasma FFA, Gly, HDL-C and decreases in plasma TG concentrations (p < 0.01). After 90 min of recovery, plasma ANGPTL4 and TG did not differ significantly from the exercise values, while plasma FFA, Gly, TC and HDL-C were significantly lower than immediately after the run. TC/HDL-C and TG/HDL-C molar ratios were significantly reduced. The exercise-induced changes in plasma ANGPTL4 correlated positively with those of FFA (r = 0.73; p < 0.02), and HDL-C (r = 0.69; p < 0.05). Positive correlation was found also between plasma ANGPTL4 and FFA concentrations after 90 min of recovery (r = 0.77; p < 0.01). Conclusions The present data suggest that increase in plasma FFA during mountain ultra-marathon run may be involved in plasma ANGPTL4 release and that increase in ANGPTL4 secretion may be a compensatory mechanism against fatty acid-induced oxidative stress. Increase in plasma HDL-C observed immediately after the run may be due to the protective effect of ANGPTL4 on HDL.
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Nimonkar AV, Weldon S, Godbout K, Panza D, Hanrahan S, Cubbon R, Xu F, Trauger JW, Gao J, Voznesensky A. A lipoprotein lipase-GPI-anchored high-density lipoprotein-binding protein 1 fusion lowers triglycerides in mice: Implications for managing familial chylomicronemia syndrome. J Biol Chem 2019; 295:2900-2912. [PMID: 31645434 PMCID: PMC7062184 DOI: 10.1074/jbc.ra119.011079] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/15/2019] [Indexed: 02/04/2023] Open
Abstract
Lipoprotein lipase (LPL) is central to triglyceride metabolism. Severely compromised LPL activity causes familial chylomicronemia syndrome (FCS), which is associated with very high plasma triglyceride levels and increased risk of life-threatening pancreatitis. Currently, no approved pharmacological intervention can acutely lower plasma triglycerides in FCS. Low yield, high aggregation, and poor stability of recombinant LPL have thus far prevented development of enzyme replacement therapy. Recently, we showed that LPL monomers form 1:1 complexes with the LPL transporter glycosylphosphatidylinositol-anchored high-density lipoprotein–binding protein 1 (GPIHBP1) and solved the structure of the complex. In the present work, we further characterized the monomeric LPL/GPIHBP1 complex and its derivative, the LPL–GPIHBP1 fusion protein, with the goal of contributing to the development of an LPL enzyme replacement therapy. Fusion of LPL to GPIHBP1 increased yields of recombinant LPL, prevented LPL aggregation, stabilized LPL against spontaneous inactivation, and made it resistant to inactivation by the LPL antagonists angiopoietin-like protein 3 (ANGPTL3) or ANGPTL4. The high stability of the fusion protein enabled us to identify LPL amino acids that interact with ANGPTL4. Additionally, the LPL–GPIHBP1 fusion protein exhibited high enzyme activity in in vitro assays. Importantly, both intravenous and subcutaneous administrations of the fusion protein lowered triglycerides in several mouse strains without causing adverse effects. These results indicate that the LPL–GPIHBP1 fusion protein has potential for use as a therapeutic for managing FCS.
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Affiliation(s)
- Amitabh V Nimonkar
- Cardiovascular and Metabolic Disease Area, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Stephen Weldon
- Novartis Biologics Center, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Kevin Godbout
- Novartis Biologics Center, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Darrell Panza
- Cardiovascular and Metabolic Disease Area, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Susan Hanrahan
- Cardiovascular and Metabolic Disease Area, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Rose Cubbon
- Cardiovascular and Metabolic Disease Area, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Fangmin Xu
- Protein Analytics, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - John W Trauger
- Cardiovascular and Metabolic Disease Area, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Jiaping Gao
- Cardiovascular and Metabolic Disease Area, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Andrei Voznesensky
- Novartis Biologics Center, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
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Reimund M, Wolska A, Risti R, Wilson S, Sviridov D, Remaley AT, Lookene A. Apolipoprotein C-II mimetic peptide is an efficient activator of lipoprotein lipase in human plasma as studied by a calorimetric approach. Biochem Biophys Res Commun 2019; 519:67-72. [PMID: 31477272 DOI: 10.1016/j.bbrc.2019.08.130] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 08/23/2019] [Indexed: 10/26/2022]
Abstract
Elevated plasma triglyceride (TG) levels are associated with higher risk of atherosclerotic cardiovascular disease. One way to reduce plasma TG is to increase the activity of lipoprotein lipase (LPL), the rate limiting enzyme in plasma TG metabolism. An apolipoprotein (apo) C-II mimetic peptide (18A-CII-a) has been recently developed that stimulated LPL activity in vitro and decreased plasma TG concentration in animal models for hypertriglyceridemia. Since this peptide can serve as a new therapeutic approach for treatment of hypertriglyceridemia, we investigated how 18A-CII-a peptide influences LPL activity in human plasma. We used recently described isothermal titration calorimetry based approach to assess the peptide, which enables the analysis in nearly undiluted human plasma. The 18A-CII-a peptide was 3.5-fold more efficient in stimulating LPL activity than full-length apoC-II in plasma sample from normolipidemic individual. Furthermore, 18A-CII-a also increased LPL activity in hypertriglyceridemic plasma samples. Unlike apoC-II, high concentrations of the 18A-CII-a peptide did not inhibit LPL activity. The increase in LPL activity after addition of 18A-CII-a or apoC-II to plasma was due to the increase of the amount of available substrate for LPL. Measurements with isolated lipoproteins revealed that the relative activation effects of 18A-CII-a and apoC-II on LPL activity were greater in smaller size lipoprotein fractions, such as remnant lipoproteins, low-density lipoproteins and high-density lipoproteins. In summary, this report describes a novel mechanism of action for stimulation of LPL activity by apoC-II mimetic peptides.
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Affiliation(s)
- Mart Reimund
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, 12618, Estonia
| | - Anna Wolska
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Robert Risti
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, 12618, Estonia
| | - Sierra Wilson
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Denis Sviridov
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Alan T Remaley
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Aivar Lookene
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, 12618, Estonia.
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Circulating Angptl3 and Angptl8 Are Increased in Patients with Hypothyroidism. BIOMED RESEARCH INTERNATIONAL 2019; 2019:3814687. [PMID: 31380419 PMCID: PMC6662479 DOI: 10.1155/2019/3814687] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/23/2019] [Accepted: 07/02/2019] [Indexed: 12/25/2022]
Abstract
Purpose Angiopoietin-like proteins (Angptls) play critical roles in biological processes, primarily in lipid metabolism. The functional state of the thyroid has a profound influence on metabolism in the human body. Therefore, the aim of this study was to investigate possible changes in serum Angptl3, 4, and 8 levels in hypothyroid patients. Methods The study included 29 patients with clinical hypothyroidism, 30 patients with subclinical hypothyroidism, and 29 healthy subjects. Baseline clinical indices, including serum thyroid function tests, were recorded and serum Angptl3, 4, and 8 levels were measured across the three groups. Results Serum Angptl3 and 8 levels were significantly higher in the hypothyroid groups compared to the control group (p < 0.05). There were no differences in Angptl4 levels among the three groups (p > 0.05). Positive correlations were identified between Angptl3 and high-density lipoprotein cholesterol (r = 0.431, p < 0.001), and there was a negative correlation between Angptl3 and total tri-iodothyronine (TT3) (r = -0.220, p = 0.047) and free tri-iodothyronine (r = - 0.279, p = 0.013) levels. Angptl8 was positively correlated with triglyceride (r = 0.267, p = 0.012) and cholesterol levels (r= 0.235, p = 0.028) but was negatively correlated with tri-iodothyronine (r = -0.24, p = 0.031). Furthermore, we used receiver operating characteristic curve analysis to evaluate the diagnostic performance of Angptl3 and 8 in discriminating thyroid dysfunction. The area under curve for detecting thyroid dysfunction based on Angptl3 and Angptl8 was 0.763. Conclusions Our data show that serum Angptl3 and 8 levels are increased in clinical and subclinical hypothyroid patients and that Angptl3 and 8 may serve as possible biomarkers of hypothyroid disease.
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Aryal B, Price NL, Suarez Y, Fernández-Hernando C. ANGPTL4 in Metabolic and Cardiovascular Disease. Trends Mol Med 2019; 25:723-734. [PMID: 31235370 DOI: 10.1016/j.molmed.2019.05.010] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/13/2019] [Accepted: 05/28/2019] [Indexed: 02/07/2023]
Abstract
Alterations in circulating lipids and ectopic lipid deposition impact on the risk of developing cardiovascular and metabolic diseases. Lipoprotein lipase (LPL) hydrolyzes fatty acids (FAs) from triglyceride (TAG)-rich lipoproteins including very low density lipoproteins (VLDLs) and chylomicrons, and regulates their distribution to peripheral tissues. Angiopoietin-like 4 (ANGPTL4) mediates the inhibition of LPL activity under different circumstances. Accumulating evidence associates ANGPTL4 directly with the risk of atherosclerosis and type 2 diabetes (T2D). This review focuses on recent findings on the role of ANGPTL4 in metabolic and cardiovascular diseases. We highlight human and murine studies that explore ANGPTL4 functions in different tissues and how these effect disease development through possible autocrine and paracrine forms of regulation.
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Affiliation(s)
- Binod Aryal
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA; Integrative Cell Signaling and Neurobiology of Metabolism Program, Yale University School of Medicine, New Haven, CT, USA; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA.
| | - Nathan L Price
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA; Integrative Cell Signaling and Neurobiology of Metabolism Program, Yale University School of Medicine, New Haven, CT, USA; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Yajaira Suarez
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA; Integrative Cell Signaling and Neurobiology of Metabolism Program, Yale University School of Medicine, New Haven, CT, USA; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA; Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Carlos Fernández-Hernando
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA; Integrative Cell Signaling and Neurobiology of Metabolism Program, Yale University School of Medicine, New Haven, CT, USA; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA; Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
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Abstract
Lipoprotein lipase (LPL) plays a central role in triglyceride (TG) metabolism. By catalyzing the hydrolysis of TGs present in TG-rich lipoproteins (TRLs), LPL facilitates TG utilization and regulates circulating TG and TRL concentrations. Until very recently, structural information for LPL was limited to homology models, presumably due to the propensity of LPL to unfold and aggregate. By coexpressing LPL with a soluble variant of its accessory protein glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) and with its chaperone protein lipase maturation factor 1 (LMF1), we obtained a stable and homogenous LPL/GPIHBP1 complex that was suitable for structure determination. We report here X-ray crystal structures of human LPL in complex with human GPIHBP1 at 2.5-3.0 Å resolution, including a structure with a novel inhibitor bound to LPL. Binding of the inhibitor resulted in ordering of the LPL lid and lipid-binding regions and thus enabled determination of the first crystal structure of LPL that includes these important regions of the protein. It was assumed for many years that LPL was only active as a homodimer. The structures and additional biochemical data reported here are consistent with a new report that LPL, in complex with GPIHBP1, can be active as a monomeric 1:1 complex. The crystal structures illuminate the structural basis for LPL-mediated TRL lipolysis as well as LPL stabilization and transport by GPIHBP1.
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Brommage R, Powell DR, Vogel P. Predicting human disease mutations and identifying drug targets from mouse gene knockout phenotyping campaigns. Dis Model Mech 2019; 12:dmm038224. [PMID: 31064765 PMCID: PMC6550044 DOI: 10.1242/dmm.038224] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Two large-scale mouse gene knockout phenotyping campaigns have provided extensive data on the functions of thousands of mammalian genes. The ongoing International Mouse Phenotyping Consortium (IMPC), with the goal of examining all ∼20,000 mouse genes, has examined 5115 genes since 2011, and phenotypic data from several analyses are available on the IMPC website (www.mousephenotype.org). Mutant mice having at least one human genetic disease-associated phenotype are available for 185 IMPC genes. Lexicon Pharmaceuticals' Genome5000™ campaign performed similar analyses between 2000 and the end of 2008 focusing on the druggable genome, including enzymes, receptors, transporters, channels and secreted proteins. Mutants (4654 genes, with 3762 viable adult homozygous lines) with therapeutically interesting phenotypes were studied extensively. Importantly, phenotypes for 29 Lexicon mouse gene knockouts were published prior to observations of similar phenotypes resulting from homologous mutations in human genetic disorders. Knockout mouse phenotypes for an additional 30 genes mimicked previously published human genetic disorders. Several of these models have helped develop effective treatments for human diseases. For example, studying Tph1 knockout mice (lacking peripheral serotonin) aided the development of telotristat ethyl, an approved treatment for carcinoid syndrome. Sglt1 (also known as Slc5a1) and Sglt2 (also known as Slc5a2) knockout mice were employed to develop sotagliflozin, a dual SGLT1/SGLT2 inhibitor having success in clinical trials for diabetes. Clinical trials evaluating inhibitors of AAK1 (neuropathic pain) and SGLT1 (diabetes) are underway. The research community can take advantage of these unbiased analyses of gene function in mice, including the minimally studied 'ignorome' genes.
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Affiliation(s)
- Robert Brommage
- Department of Metabolism Research, Lexicon Pharmaceuticals, 8800 Technology Forest Place, The Woodlands, TX 77381, USA
| | - David R Powell
- Department of Metabolism Research, Lexicon Pharmaceuticals, 8800 Technology Forest Place, The Woodlands, TX 77381, USA
| | - Peter Vogel
- St. Jude Children's Research Hospital, Pathology, MS 250, Room C5036A, 262 Danny Thomas Place, Memphis, TN 38105, USA
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36
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Kovrov O, Kristensen KK, Larsson E, Ploug M, Olivecrona G. On the mechanism of angiopoietin-like protein 8 for control of lipoprotein lipase activity. J Lipid Res 2019; 60:783-793. [PMID: 30686789 PMCID: PMC6446706 DOI: 10.1194/jlr.m088807] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/05/2018] [Indexed: 01/20/2023] Open
Abstract
Angiopoietin-like (ANGPTL) 8 is a secreted inhibitor of LPL, a key enzyme in plasma triglyceride metabolism. It was previously reported that ANGPTL8 requires another member of the ANGPTL family, ANGPTL3, to act on LPL. ANGPTL3, much like ANGPTL4, is a physiologically relevant regulator of LPL activity, which causes irreversible inactivation of the enzyme. Here, we show that ANGPTL8 can form complexes with either ANGPTL3 or ANGPTL4 when the proteins are refolded together from their denatured states. In contrast to the augmented inhibitory effect of the ANGPTL3/ANGPTL8 complex on LPL activity, the ANGPTL4/ANGPTL8 complex is less active compared with ANGPTL4 alone. In our experiments, all three members of the ANGPTL family use the same mechanism to inactivate LPL, which involves dissociation of active dimeric LPL to monomers. This inactivation can be counteracted by the presence of glycosylphosphatidylinositol-anchored HDL binding protein 1, the endothelial LPL transport protein previously known to protect LPL from spontaneous and ANGPTL4-catalyzed inactivation. Our data demonstrate that ANGPTL8 may function as an important metabolic switch, by forming complexes with ANGPTL3, or with ANGPTL4, in order to direct the flow of energy from triglycerides in blood according to the needs of the body.
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Affiliation(s)
- Oleg Kovrov
- Department of Medical Biosciences, Umeå University, Umeå, Sweden
| | - Kristian Kølby Kristensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Erika Larsson
- Department of Medical Biosciences, Umeå University, Umeå, Sweden
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
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37
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Nyrén R, Makoveichuk E, Malla S, Kersten S, Nilsson SK, Ericsson M, Olivecrona G. Lipoprotein lipase in mouse kidney: effects of nutritional status and high-fat diet. Am J Physiol Renal Physiol 2019; 316:F558-F571. [PMID: 30698048 DOI: 10.1152/ajprenal.00474.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Activity of lipoprotein lipase (LPL) is high in mouse kidney, but the reason is poorly understood. The aim was to characterize localization, regulation, and function of LPL in kidney of C57BL/6J mice. We found LPL mainly in proximal tubules, localized inside the tubular epithelial cells, under all conditions studied. In fed mice, some LPL colocalized with the endothelial markers CD31 and GPIHBP1 and could be removed by perfusion with heparin, indicating a vascular location. The role of angiopoietin-like protein 4 (ANGPTL4) for nutritional modulation of LPL activity was studied in wild-type and Angptl4-/- mice. In Angptl4-/- mice, kidney LPL activity remained high in fasted animals, indicating that ANGPTL4 is involved in suppression of LPL activity on fasting, like in adipose tissue. The amount of ANGPTL4 protein in kidney was low, and the protein appeared smaller in size, compared with ANGPTL4 in heart and adipose tissue. To study the influence of obesity, mice were challenged with high-fat diet for 22 wk, and LPL was studied after an overnight fast compared with fasted mice given food for 3 h. High-fat diet caused blunting of the normal adaptation of LPL activity to feeding/fasting in adipose tissue, but in kidneys this adaptation was lost only in male mice. LPL activity increases to high levels in mouse kidney after feeding, but as no difference in uptake of chylomicron triglycerides in kidneys is found between fasted and fed states, our data confirm that LPL appears to have a minor role for lipid uptake in this organ.
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Affiliation(s)
- Rakel Nyrén
- Department of Medical Biosciences/Physiological Chemistry, Umeå University , Umeå , Sweden
| | - Elena Makoveichuk
- Department of Medical Biosciences/Physiological Chemistry, Umeå University , Umeå , Sweden
| | - Sandhya Malla
- Department of Medical Biosciences/Physiological Chemistry, Umeå University , Umeå , Sweden.,Wallenberg Center for Molecular Medicine, Umeå University , Umeå , Sweden
| | - Sander Kersten
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition and Health, Wageningen University , Wageningen , The Netherlands
| | - Stefan K Nilsson
- Department of Medical Biosciences/Physiological Chemistry, Umeå University , Umeå , Sweden
| | - Madelene Ericsson
- Department of Medical Biosciences/Physiological Chemistry, Umeå University , Umeå , Sweden
| | - Gunilla Olivecrona
- Department of Medical Biosciences/Physiological Chemistry, Umeå University , Umeå , Sweden
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38
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Shrestha P, van de Sluis B, Dullaart RP, van den Born J. Novel aspects of PCSK9 and lipoprotein receptors in renal disease-related dyslipidemia. Cell Signal 2019; 55:53-64. [DOI: 10.1016/j.cellsig.2018.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/01/2018] [Accepted: 12/03/2018] [Indexed: 12/12/2022]
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Geladari E, Tsamadia P, Vallianou NG. ANGPTL3 Inhibitors - Their Role in Cardiovascular Disease Through Regulation of Lipid Metabolism. Circ J 2018; 83:267-273. [PMID: 30504621 DOI: 10.1253/circj.cj-18-0442] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Elevated plasma lipid levels are linked to atherosclerosis, a hallmark for coronary artery disease (CAD), documented by animal studies as well as angiographic and clinical studies. The ability to treat hyperlipidemia through lifestyle changes and lipid-lowering agents has been related to the slow progression of atherosclerosis and decreased incidence of major coronary events. Angiopoietin-like proteins (ANGPTLs) are a family of secreted glycoproteins expressed in the liver that share common domain characteristics with angiopoietins, the main regulators of angiogenesis. Although ANGPTLs cannot bind the angiopoietin receptors expressed on endothelial cells, 2 ANGPTL family members (ANGPTL3 and ANGPTL4) have clinical importance because of their unambiguous effects on lipoprotein metabolism in mice and humans. The regulation of plasma lipid levels by ANGPTL3 is controlled via affecting lipoprotein lipase and endothelial lipase-mediated hydrolysis of triglycerides (TGs) and phospholipids. ANGPTL 3, along with the other 2 members, 4 and 8, is a key to balancing the distribution of circulating TGs between white adipose tissue (WAT) and oxidative tissues. Thus, ongoing trials with newly discovered medications in the form of monoclonal antibodies or antisense oligonucleotides with novel targets are under analysis and may represent a fresh frontier in the treatment of hyperlipidemia and CAD.
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Affiliation(s)
- Eleni Geladari
- Department of Internal Medicine, Evangelismos General Hospital
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40
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Surendran RP, Udayyapan SD, Clemente-Postigo M, Havik SR, Schimmel AWM, Tinahones F, Nieuwdorp M, Dallinga-Thie GM. Decreased GPIHBP1 protein levels in visceral adipose tissue partly underlie the hypertriglyceridemic phenotype in insulin resistance. PLoS One 2018; 13:e0205858. [PMID: 30408040 PMCID: PMC6224034 DOI: 10.1371/journal.pone.0205858] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/02/2018] [Indexed: 01/29/2023] Open
Abstract
GPIHBP1 is a protein localized at the endothelial cell surface that facilitates triglyceride (TG) lipolysis by binding lipoprotein lipase (LPL). Whether Glycosyl Phosphatidyl Inositol high density lipoprotein binding protein 1 (GPIHBP1) function is impaired and may underlie the hyperTG phenotype observed in type 2 diabetes is not yet established. To elucidate the mechanism underlying impaired TG homeostasis in insulin resistance state we studied the effect of insulin on GPIHBP1 protein expression in human microvascular endothelial cells (HMVEC) under flow conditions. Next, we assessed visceral adipose tissue GPIHBP1 protein expression in type 2 diabetes Leprdb/db mouse model as well as in subjects with ranging levels of insulin resistance. We report that insulin reduces the expression of GPIHBP1 protein in HMVECs. Furthermore, GPIHBP1 protein expression in visceral adipose tissue in Leprdb/db mice is significantly reduced as is the active monomeric form of GPIHBP1 as compared to Leprdb/m mice. A similar decrease in GPIHBP1 protein was observed in subjects with increased body weight. GPIHBP1 protein expression was negatively associated with insulin and HOMA-IR. In conclusion, our data suggest that decreased GPIHBP1 availability in insulin resistant state may hamper peripheral lipolysis capacity.
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Affiliation(s)
- R. Preethi Surendran
- Department of Experimental Vascular Medicine, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
| | - Shanti D. Udayyapan
- Department of Experimental Vascular Medicine, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
| | - Mercedes Clemente-Postigo
- Unidad de Gestión Clínica Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Complejo Hospitalario de Málaga (Virgen de la Victoria)/Universidad de Malaga, Malaga, Spain
- CIBER Fisiopatologia de la Obesidad y Nutrición (CB06/03), Barcelona, Spain
| | - Stefan R. Havik
- Department of Experimental Vascular Medicine, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
| | - Alinda W. M. Schimmel
- Department of Experimental Vascular Medicine, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
| | - Fransisco Tinahones
- Unidad de Gestión Clínica Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Complejo Hospitalario de Málaga (Virgen de la Victoria)/Universidad de Malaga, Malaga, Spain
- CIBER Fisiopatologia de la Obesidad y Nutrición (CB06/03), Barcelona, Spain
| | - Max Nieuwdorp
- Department of Vascular Medicine, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
| | - Geesje M. Dallinga-Thie
- Department of Experimental Vascular Medicine, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
- Unidad de Gestión Clínica Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Complejo Hospitalario de Málaga (Virgen de la Victoria)/Universidad de Malaga, Malaga, Spain
- * E-mail:
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41
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Chen LY, Xia XD, Zhao ZW, Gong D, Ma XF, Yu XH, Zhang Q, Wang SQ, Dai XY, Zheng XL, Zhang DW, Yin WD, Tang CK. MicroRNA-377 Inhibits Atherosclerosis by Regulating Triglyceride Metabolism Through the DNA Methyltransferase 1 in Apolipoprotein E-Knockout Mice. Circ J 2018; 82:2861-2871. [PMID: 30232292 DOI: 10.1253/circj.cj-18-0410] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Lipoprotein lipase (LPL) plays an important role in triglyceride metabolism. It is translocated across endothelial cells to reach the luminal surface of capillaries by glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1), where it hydrolyzes triglycerides in lipoproteins. MicroRNA 377 (miR-377) is highly associated with lipid levels. However, how miR-377 regulates triglyceride metabolism and whether it is involved in the development of atherosclerosis remain largely unexplored. Methods and Results: The clinical examination displayed that miR-377 expression was markedly lower in plasma from patients with hypertriglyceridemia compared with non-hypertriglyceridemic subjects. Bioinformatics analyses and a luciferase reporter assay showed that DNA methyltransferase 1 (DNMT1) was a target gene of miR-377. Moreover, miR-377 increased LPL binding to GPIHBP1 by directly targeting DNMT1 in human umbilical vein endothelial cells (HUVECs) and apolipoprotein E (ApoE)-knockout (KO) mice aorta endothelial cells (MAECs). In vivo, hematoxylin-eosin (H&E), Oil Red O and Masson's trichrome staining showed that ApoE-KO mice treated with miR-377 developed less atherosclerotic plaques, accompanied by reduced plasma triglyceride levels. CONCLUSIONS It is concluded that miR-377 upregulates GPIHBP1 expression, increases the LPL binding to GPIHBP1, and reduces plasma triglyceride levels, likely through targeting DNMT1, inhibiting atherosclerosis in ApoE-KO mice.
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Affiliation(s)
- Ling-Yan Chen
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Xiao-Dan Xia
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Zhen-Wang Zhao
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Duo Gong
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Xiao-Feng Ma
- Department of Internal Medicine-Cardiovascular, Nanhua Hospital, University of South China
| | - Xiao-Hua Yu
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Qiang Zhang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Si-Qi Wang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Xiao-Yan Dai
- Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou, Medical University
| | - Xi-Long Zheng
- Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Health Sciences Center
| | - Da-Wei Zhang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, University of Alberta
| | - Wei-Dong Yin
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Chao-Ke Tang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
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42
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Liu C, Li L, Guo D, Lv Y, Zheng X, Mo Z, Xie W. Lipoprotein lipase transporter GPIHBP1 and triglyceride-rich lipoprotein metabolism. Clin Chim Acta 2018; 487:33-40. [PMID: 30218660 DOI: 10.1016/j.cca.2018.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/11/2018] [Accepted: 09/11/2018] [Indexed: 02/05/2023]
Abstract
Increased plasma triglyceride serves as an independent risk factor for cardiovascular disease (CVD). Lipoprotein lipase (LPL), which hydrolyzes circulating triglyceride, plays a crucial role in normal lipid metabolism and energy balance. Hypertriglyceridemia is possibly caused by gene mutations resulting in LPL dysfunction. There are many factors that both positively and negatively interact with LPL thereby impacting TG lipolysis. Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), a newly identified factor, appears essential for transporting LPL to the luminal side of the blood vessel and offering a platform for TG hydrolysis. Numerous lines of evidence indicate that GPIHBP1 exerts distinct functions and plays diverse roles in human triglyceride-rich lipoprotein (TRL) metabolism. In this review, we discuss the GPIHBP1 gene, protein, its expression and function and subsequently focus on its regulation and provide critical evidence supporting its role in TRL metabolism. Underlying mechanisms of action are highlighted, additional studies discussed and potential therapeutic targets reviewed.
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Affiliation(s)
- Chuhao Liu
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China; 2016 Class of Excellent Doctor, University of South China, Hengyang 421001, Hunan, China
| | - Liang Li
- Department of Pathophysiology, University of South China, Hengyang 421001, Hunan, China
| | - Dongming Guo
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China
| | - Yuncheng Lv
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China
| | - XiLong Zheng
- Department of Biochemistry and Molecular Biology, The Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, The University of Calgary, Health Sciences Center, 3330 Hospital Dr NW, Calgary T2N 4N1, Alberta, Canada; Key Laboratory of Molecular Targets & Clinical Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou 511436, Guangdong, China
| | - Zhongcheng Mo
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China.
| | - Wei Xie
- Clinical Anatomy & Reproductive Medicine Application Institute, University of South China, Hengyang 421001, Hunan, China.
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43
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A disordered acidic domain in GPIHBP1 harboring a sulfated tyrosine regulates lipoprotein lipase. Proc Natl Acad Sci U S A 2018; 115:E6020-E6029. [PMID: 29899144 DOI: 10.1073/pnas.1806774115] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The intravascular processing of triglyceride-rich lipoproteins depends on lipoprotein lipase (LPL) and GPIHBP1, a membrane protein of endothelial cells that binds LPL within the subendothelial spaces and shuttles it to the capillary lumen. In the absence of GPIHBP1, LPL remains mislocalized within the subendothelial spaces, causing severe hypertriglyceridemia (chylomicronemia). The N-terminal domain of GPIHBP1, an intrinsically disordered region (IDR) rich in acidic residues, is important for stabilizing LPL's catalytic domain against spontaneous and ANGPTL4-catalyzed unfolding. Here, we define several important properties of GPIHBP1's IDR. First, a conserved tyrosine in the middle of the IDR is posttranslationally modified by O-sulfation; this modification increases both the affinity of GPIHBP1-LPL interactions and the ability of GPIHBP1 to protect LPL against ANGPTL4-catalyzed unfolding. Second, the acidic IDR of GPIHBP1 increases the probability of a GPIHBP1-LPL encounter via electrostatic steering, increasing the association rate constant (kon) for LPL binding by >250-fold. Third, we show that LPL accumulates near capillary endothelial cells even in the absence of GPIHBP1. In wild-type mice, we expect that the accumulation of LPL in close proximity to capillaries would increase interactions with GPIHBP1. Fourth, we found that GPIHBP1's IDR is not a key factor in the pathogenicity of chylomicronemia in patients with the GPIHBP1 autoimmune syndrome. Finally, based on biophysical studies, we propose that the negatively charged IDR of GPIHBP1 traverses a vast space, facilitating capture of LPL by capillary endothelial cells and simultaneously contributing to GPIHBP1's ability to preserve LPL structure and activity.
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44
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Cushing EM, Sylvers KL, Chi X, Shetty SK, Davies BSJ. Novel GPIHBP1-independent pathway for clearance of plasma TGs in Angptl4-/-Gpihbp1-/- mice. J Lipid Res 2018; 59:1230-1243. [PMID: 29739862 DOI: 10.1194/jlr.m084749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/28/2018] [Indexed: 02/07/2023] Open
Abstract
Mice lacking glycosylphosphatidylinositol-anchored HDL-binding protein 1 (GPIHBP1) are unable to traffic LPL to the vascular lumen. Thus, triglyceride (TG) clearance is severely blunted, and mice are extremely hypertriglyceridemic. Paradoxically, mice lacking both GPIHBP1 and the LPL regulator, angiopoietin-like 4 (ANGPTL4), are far less hypertriglyceridemic. We sought to determine the mechanism by which Angptl4-/-Gpihbp1-/- double-knockout mice clear plasma TGs. We confirmed that, on a normal chow diet, plasma TG levels were lower in Angptl4-/-Gpihbp1-/- mice than in Gpihbp1-/- mice; however, the difference disappeared with administration of a high-fat diet. Although LPL remained mislocalized in double-knockout mice, plasma TG clearance in brown adipose tissue (BAT) increased compared with Gpihbp1-/- mice. Whole lipoprotein uptake was observed in the BAT of both Gpihbp1-/- and Angptl4-/-Gpihbp1-/- mice, but BAT lipase activity was significantly higher in the double-knockout mice. We conclude that Angptl4-/-Gpihbp1-/- mice clear plasma TGs primarily through a slow and noncanonical pathway that includes the uptake of whole lipoprotein particles.
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Affiliation(s)
- Emily M Cushing
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Kelli L Sylvers
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Xun Chi
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Shwetha K Shetty
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Brandon S J Davies
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242
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45
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Analysis of circulating angiopoietin-like protein 3 and genetic variants in lipid metabolism and liver health: the DiOGenes study. GENES AND NUTRITION 2018; 13:7. [PMID: 29619113 PMCID: PMC5879874 DOI: 10.1186/s12263-018-0597-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/14/2018] [Indexed: 12/20/2022]
Abstract
Background Angiopoietin-like protein 3 (ANGPTL3), a liver-derived protein, plays an important role in the lipid and lipoprotein metabolism. Using data available from the DiOGenes study, we assessed the link with clinical improvements (weight, plasma lipid, and insulin levels) and changes in liver markers, alanine aminotransferase, aspartate aminotransferase (AST), adiponectin, fetuin A and B, and cytokeratin 18 (CK-18), upon low-calorie diet (LCD) intervention. We also examined the role of genetic variation in determining the level of circulating ANGPTL3 and the relation between the identified genetic markers and markers of hepatic steatosis. Methods DiOGenes is a multicenter, controlled dietary intervention where obese participants followed an 8-week LCD (800 kcal/day, using a meal replacement product). Plasma ANGPTL3 and liver markers were measured using the SomaLogic (Boulder, CO) platform. Protein quantitative trait locus (pQTL) analyses assessed the link between more than four million common variants and the level of circulating ANGPTL3 at baseline and changes in levels during the LCD intervention. Results Changes in ANGPTL3 during weight loss showed only marginal association with changes in triglycerides (nominal p = 0.02) and insulin (p = 0.04); these results did not remain significant after correcting for multiple testing. However, significant association (after multiple-testing correction) were observed between changes in ANGPTL3 and AST during weight loss (p = 0.004) and between ANGPTL3 and CK-18 (baseline p = 1.03 × 10−7, during weight loss p = 1.47 × 10−13). Our pQTL study identified two loci significantly associated with changes in ANGPTL3. One of these loci (the APOA4-APOA5-ZNF259-BUD13 gene cluster) also displayed significant association with changes in CK-18 levels during weight loss (p = 0.007). Conclusion We clarify the link between circulating levels of ANGPTL3 and specific markers of liver function. We demonstrate that changes in ANGPLT3 and CK-18 during LCD are under genetic control from trans-acting variants. Our results suggest an extended function of ANGPTL3 in the inflammatory state of liver steatosis and toward liver metabolic processes. Electronic supplementary material The online version of this article (10.1186/s12263-018-0597-3) contains supplementary material, which is available to authorized users.
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Larsson M, Allan CM, Heizer PJ, Tu Y, Sandoval NP, Jung RS, Walzem RL, Beigneux AP, Young SG, Fong LG. Impaired thermogenesis and sharp increases in plasma triglyceride levels in GPIHBP1-deficient mice during cold exposure. J Lipid Res 2018; 59:706-713. [PMID: 29449313 DOI: 10.1194/jlr.m083832] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Indexed: 01/11/2023] Open
Abstract
Glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1), an endothelial cell protein, binds LPL in the subendothelial spaces and transports it to the capillary lumen. In Gpihbp1-/- mice, LPL remains stranded in the subendothelial spaces, causing hypertriglyceridemia, but how Gpihbp1-/- mice respond to metabolic stress (e.g., cold exposure) has never been studied. In wild-type mice, cold exposure increases LPL-mediated processing of triglyceride-rich lipoproteins (TRLs) in brown adipose tissue (BAT), providing fuel for thermogenesis and leading to lower plasma triglyceride levels. We suspected that defective TRL processing in Gpihbp1-/- mice might impair thermogenesis and blunt the fall in plasma triglyceride levels. Indeed, Gpihbp1-/- mice exhibited cold intolerance, but the effects on plasma triglyceride levels were paradoxical. Rather than falling, the plasma triglyceride levels increased sharply (from ∼4,000 to ∼15,000 mg/dl), likely because fatty acid release by peripheral tissues drives hepatic production of TRLs that cannot be processed. We predicted that the sharp increase in plasma triglyceride levels would not occur in Gpihbp1-/-Angptl4-/- mice, where LPL activity is higher and baseline plasma triglyceride levels are lower. Indeed, the plasma triglyceride levels in Gpihbp1-/-Angptl4-/- mice fell during cold exposure. Metabolic studies revealed increased levels of TRL processing in the BAT of Gpihbp1-/-Angptl4-/- mice.
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Affiliation(s)
- Mikael Larsson
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095.
| | - Christopher M Allan
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Patrick J Heizer
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Yiping Tu
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Norma P Sandoval
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Rachel S Jung
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Rosemary L Walzem
- Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, TX 77843
| | - Anne P Beigneux
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Stephen G Young
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095; Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095.
| | - Loren G Fong
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095.
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Su X, Peng DQ. New insights into ANGPLT3 in controlling lipoprotein metabolism and risk of cardiovascular diseases. Lipids Health Dis 2018; 17:12. [PMID: 29334984 PMCID: PMC5769531 DOI: 10.1186/s12944-018-0659-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/05/2018] [Indexed: 02/07/2023] Open
Abstract
Dyslipidemia, characterized by elevation of plasma low density lipoprotein cholesterol (LDL-C), triglyceride (TG) and reduction of plasma high density lipoprotein cholesterol (HDL-C), has been verified as a causal risk factor for cardiovascular diseases (CVD), leading to a high mortality rate in general population. It is important to understand the molecular metabolism underlying dyslipidemia in order to reduce the risk and to develop effective therapeutic approaches against CVD. ANGPTL3 (human) or Angptl3 (mouse), one member of the angiopoietin-like protein (ANGPTL) family, has been identified as an important regulator of lipid metabolism by inhibiting LPL and EL activity. Results have demonstrated that inactivation of Angptl3 in mice could obviously reduce the level of TG, LDL-C and the atherosclerotic lesion size, leading to a lower risk for dyslipidemia and CVD. Additionally, in humans, carriers with homozygous LOF mutations in ANGPTL3 have lower plasma LDL-C, TG levels and lower risk of atherosclerosis compared to the non-carriers. Here, we collect the latest data and results, giving a new insight into the important role of ANGPTL3 in controlling lipoprotein metabolism. Finally, we introduce two update reports on the antisense oligonucleotide and monoclonal antibody-based inactivation of ANGPTL3 in human clinical trials, to identify that ANGPTL3 could be a novel and effective target for the treatment of dyslipidemia and CVD.
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Affiliation(s)
- Xin Su
- Department of Cardiovascular Medicine, the Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Dao-Quan Peng
- Department of Cardiovascular Medicine, the Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China.
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Abstract
Triglycerides and cholesterol circulate in the bloodstream as part of various lipoprotein particles. Three members of the angiopoietin-like (ANGPTL) protein family - ANGPTL3, ANGPTL4 and ANGPTL8 - have emerged as important regulators of plasma lipoprotein levels by inhibiting the enzyme lipoprotein lipase. Here, I review the role of ANGPTL3 in lipoprotein metabolism. In contrast to ANGPTL4 and ANGPTL8, ANGPTL3 is exclusively produced in the liver and can therefore be classified as a true hepatokine. ANGPTL3 cooperates with ANGPTL8 to inhibit lipoprotein lipase and is mostly active after feeding, whereas ANGPTL4 is mostly active after fasting. Inactivation of ANGPTL3 in mice reduces plasma triglyceride and free fatty acid levels and suppresses atherosclerosis. In humans, homozygous loss-of-function mutations in ANGPTL3 lead to low plasma levels of low-density lipoproteins, high-density lipoproteins and triglycerides, a condition referred to as familial combined hypolipidaemia. Heterozygous carriers of loss-of-function mutations in ANGPTL3 have a lower risk of coronary artery disease than non-carriers. At present, researchers are investigating antisense oligonucleotide and monoclonal antibody-based inactivation of ANGPTL3 in human clinical trials for the therapeutic management of dyslipidaemia and atherosclerosis. Thus, ANGPTL3 is an important liver-derived regulator of lipoprotein metabolism that holds considerable promise as a target for atherosclerosis.
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Affiliation(s)
- Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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Chi X, Britt EC, Shows HW, Hjelmaas AJ, Shetty SK, Cushing EM, Li W, Dou A, Zhang R, Davies BSJ. ANGPTL8 promotes the ability of ANGPTL3 to bind and inhibit lipoprotein lipase. Mol Metab 2017; 6:1137-1149. [PMID: 29031715 PMCID: PMC5641604 DOI: 10.1016/j.molmet.2017.06.014] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE Several members of the angiopoietin-like (ANGPTL) family of proteins, including ANGPTL3 and ANGPTL8, regulate lipoprotein lipase (LPL) activity. Deficiency in either ANGPTL3 or ANGPTL8 reduces plasma triglyceride levels and increases LPL activity, whereas overexpression of either protein does the opposite. Recent studies suggest that ANGPTL8 may functionally interact with ANGPTL3 to alter clearance of plasma triglycerides; however, the nature of this interaction has remained elusive. We tested the hypothesis that ANGPTL8 forms a complex with ANGPTL3 and that this complex is necessary for the inhibition of vascular LPL by ANGPTL3. METHODS We analyzed the interactions of ANGPTL3 and ANGPTL8 with each other and with LPL using co-immunoprecipitation, western blotting, lipase activity assays, and the NanoBiT split-luciferase system. We also used adenovirus injection to overexpress ANGPTL3 in mice that lacked ANGPTL8. RESULTS We found that ANGPTL3 or ANGPTL8 alone could only inhibit LPL at concentrations that far exceeded physiological levels, especially when LPL was bound to its endothelial cell receptor/transporter GPIHBP1 (glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1). Physical interaction was observed between ANGPTL3 and ANGPTL8 when the proteins were co-expressed, and co-expression with ANGPTL3 greatly enhanced the secretion of ANGPTL8. Importantly, ANGPTL3-ANGPTL8 complexes had a dramatically increased ability to inhibit LPL compared to either protein alone. Adenovirus experiments showed that 2-fold overexpression of ANGPTL3 significantly increased plasma triglycerides only in the presence of ANGPTL8. Protein interaction assays showed that ANGPTL8 greatly increased the ability of ANGPTL3 to bind LPL. CONCLUSIONS Together, these data indicate that ANGPTL8 binds to ANGPTL3 and that this complex is necessary for ANGPTL3 to efficiently bind and inhibit LPL.
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Affiliation(s)
- Xun Chi
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Emily C Britt
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Hannah W Shows
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Alexander J Hjelmaas
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Shwetha K Shetty
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Emily M Cushing
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Wendy Li
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Alex Dou
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Ren Zhang
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, 540 East Canfield Street, Detroit, MI 48201, USA
| | - Brandon S J Davies
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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Angiopoietin-like 4 directs uptake of dietary fat away from adipose during fasting. Mol Metab 2017; 6:809-818. [PMID: 28752045 PMCID: PMC5518724 DOI: 10.1016/j.molmet.2017.06.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/09/2017] [Accepted: 06/14/2017] [Indexed: 12/28/2022] Open
Abstract
Objective Angiopoietin-like 4 (ANGPTL4) is a fasting-induced inhibitor of lipoprotein lipase (LPL) and a regulator of plasma triglyceride metabolism. Here, we examined the kinetics of Angptl4 induction and tested the hypothesis that ANGPTL4 functions physiologically to reduce triglyceride delivery to adipose tissue during nutrient deprivation. Methods Gene expression, LPL activity, and triglyceride uptake were examined in fasted and fed wild-type and Angptl4−/− mice. Results Angptl4 was strongly induced early in fasting, and this induction was suppressed in mice with access to food during the light cycle. Fasted Angptl4−/− mice manifested increased LPL activity and triglyceride uptake in adipose tissue compared to wild-type mice. Conclusions Angptl4 is induced early in fasting to divert uptake of fatty acids and triglycerides away from adipose tissues. •Angptl4 is induced within the first few hours of fasting. •Angptl4 expression is driven by fasting rather than circadian rhythms. •Fasted Angptl4−/− mice have increased triglyceride uptake in adipose tissue. •Angptl4−/− mice also have increased LPL activity specifically in adipose tissue. •Data support a model where ANGPTL4 acts locally in adipose during fasting.
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