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Sustar U, Groselj U, Khan SA, Shafi S, Khan I, Kovac J, Bizjan BJ, Battelino T, Sadiq F. A homozygous variant in the GPIHBP1 gene in a child with severe hypertriglyceridemia and a systematic literature review. Front Genet 2022; 13:983283. [PMID: 36051701 PMCID: PMC9424485 DOI: 10.3389/fgene.2022.983283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Due to nonspecific symptoms, rare dyslipidaemias are frequently misdiagnosed, overlooked, and undertreated, leading to increased risk for severe cardiovascular disease, pancreatitis and/or multiple organ failures before diagnosis. Better guidelines for the recognition and early diagnosis of rare dyslipidaemias are urgently required. Methods: Genomic DNA was isolated from blood samples of a Pakistani paediatric patient with hypertriglyceridemia, and from his parents and siblings. Next-generation sequencing (NGS) was performed, and an expanded dyslipidaemia panel was employed for genetic analysis. Results: The NGS revealed the presence of a homozygous missense pathogenic variant c.230G>A (NM_178172.6) in exon 3 of the GPIHBP1 (glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1) gene resulting in amino acid change p.Cys77Tyr (NP_835466.2). The patient was 5.5 years old at the time of genetic diagnosis. The maximal total cholesterol and triglyceride levels were measured at the age of 10 months (850.7 mg/dl, 22.0 mmol/L and 5,137 mg/dl, 58.0 mmol/L, respectively). The patient had cholesterol deposits at the hard palate, eruptive xanthomas, lethargy, poor appetite, and mild splenomegaly. Both parents and sister were heterozygous for the familial variant in the GPIHBP1 gene. Moreover, in the systematic review, we present 62 patients with pathogenic variants in the GPIHBP1 gene and clinical findings, associated with hyperlipoproteinemia. Conclusion: In a child with severe hypertriglyceridemia, we identified a pathogenic variant in the GPIHBP1 gene causing hyperlipoproteinemia (type 1D). In cases of severe elevations of plasma cholesterol and/or triglycerides genetic testing for rare dyslipidaemias should be performed as soon as possible for optimal therapy and patient management.
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Affiliation(s)
- Ursa Sustar
- Department of Endocrinology, Diabetes and Metabolism, University Children’s Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Urh Groselj
- Department of Endocrinology, Diabetes and Metabolism, University Children’s Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
- *Correspondence: Urh Groselj, ; Fouzia Sadiq,
| | - Sabeen Abid Khan
- Department of Paediatrics, Shifa College of Medicine, Shifa Tameer-e-Millat University, Islamabad, Pakistan
| | - Saeed Shafi
- Department of Anatomy, Shifa Tameer-e-Millat University, Islamabad, Pakistan
| | - Iqbal Khan
- Department of Vascular Surgery, Shifa International Hospital, Islamabad, Pakistan
- Department of Vascular Surgery, Shifa Tameer-e-Millat University, Islamabad, Pakistan
| | - Jernej Kovac
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Clinical Institute for Special Laboratory Diagnostics, University Children’s Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Barbara Jenko Bizjan
- Clinical Institute for Special Laboratory Diagnostics, University Children’s Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Tadej Battelino
- Department of Endocrinology, Diabetes and Metabolism, University Children’s Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Fouzia Sadiq
- Directorate of Research, Shifa Tameer-e-Millat University, Islamabad, Pakistan
- *Correspondence: Urh Groselj, ; Fouzia Sadiq,
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Du X, Gu H, Sun Y, Hu Y. Ly-6D of Japanese flounder (Paralichthys olivaceus) functions as a complement regulator and promotes host clearance of pathogen. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 122:104104. [PMID: 33891970 DOI: 10.1016/j.dci.2021.104104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
The Lymphocyte antigen-6 (Ly-6) superfamily has been considered to play an important role in the innate immunity of mammals. The functions of Ly-6 proteins are diverse since their low sequence homology. Currently, the function of Ly-6D, a member of Ly-6 family proteins, is completely unknown in teleost. In the present study, we identified and characterized a Ly-6D homologue (named PoLy-6D) from the teleost fish Paralichthys olivaceus and examined its immune function. PoLy-6D possesses a hydrophobic signal peptide, a LU domain including a conserved "LXCXXC" motif in N-terminus and a "CCXXXXCN" motif in C-terminus. Under normal physiological condition, PoLy-6D expression distributes in all the examined tissues, the highest three tissues are successively spleen, head kidney, and blood. When infected by extracellular and intracellular bacterial pathogens and viral pathogen, PoLy-6D expression was induced and the patterns vary with different types of microbial pathogens infection and different immune tissues. In vitro experiment showed recombinant PoLy-6D (rPoLy-6D) inhibited the lysis of rabbit red blood cells by serum and selectively improved bacterial survival in serum. After serum were treated by antibody of rPoLy-6D, bacteriostatic effect of serum was obviously enhanced. These results indicate the importance of PoLy-6D as a complement regulator. rPoLy-6D possessed the binding activity to multiple bacteria but did not exhibit antimicrobial activities. The interaction between rPoLy-6D and bacteria suggests that PoLy-6D is involved in host clearance of pathogens probably by serving as a receptor for pathogens. Overexpression of PoLy-6D in vivo promoted the host defense against invading E. piscicida. These findings add new insights into the regulation mechanism of the complement system in teleost and emphasize the importance of Ly-6D products for the control of pathogen infection.
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Affiliation(s)
- Xiangyu Du
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, 570228, PR China; Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, Haikou, 571101, China
| | - Hanjie Gu
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, Haikou, 571101, China; Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Haikou, 571101, China
| | - Yun Sun
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, 570228, PR China.
| | - Yonghua Hu
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, Haikou, 571101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China; Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Haikou, 571101, China.
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3
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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: 20] [Impact Index Per Article: 6.7] [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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Wang F, Chen S, Ren L, Wang Y, Li Z, Song T, Zhang H, Yang Q. The Effect of Silibinin on Protein Expression Profile in White Adipose Tissue of Obese Mice. Front Pharmacol 2020; 11:55. [PMID: 32184719 PMCID: PMC7059093 DOI: 10.3389/fphar.2020.00055] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/20/2020] [Indexed: 01/07/2023] Open
Abstract
Objective To investigate the effect of silibinin on the protein expression profile of white adipose tissue (WAT) in obese mice by using Tandem Mass Tag (TMT) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods According to experimental requirements, 36 C57BL/6JC mice were randomly divided into normal diet group (WC group), high fat diet group (WF group), and high fat diet + silibinin group (WS group). WS group was intragastrically administered with 54 mg/kg body weight of silibinin, and the WC group and the WF group were intragastrically administered with equal volume of normal saline. Serum samples were collected to detect fasting blood glucose and blood lipids. IPGTT was used to measure the blood glucose value at each time point and calculate the area under the glucose curve. TMT combined with LC-MS/MS were used to study the expression of WAT, and its cellular processes, biological processes, corresponding molecular functions, and related network molecular mechanisms were analyzed by bioinformatics. Finally, RT-PCR and LC-MS/MS were used to detect the mRNA and protein expressions of FABP5, Plin4, GPD1, and AGPAT2, respectively. Results Although silibinin did not reduce the mice's weight, it did improve glucose metabolism. In addition, silibinin decreased the concentration of TC, TG, and LDL-C and increased the concentration of HDL-C in the serum of mice. In the WF/WS group, 182 differentially expressed proteins were up-regulated and 159 were down-regulated. While in the WS/WF group, 362 differentially expressed proteins were up-regulated and 176 were down-regulated. Further analysis found that these differential proteins are mainly distributed in the peroxisome proliferation-activated receptor (PPAR), lipolysis of fat cells, metabolism of glycerides, oxidative phosphorylation, and other signaling pathways, and participate in cell processes and lipid metabolism through catalysis and integration functions. Specifically, silibinin reduced the expression of several key factors such as FABP5, Plin4, GPD1, and AGPTA2. Conclusion High fat diet (HFD) can increase the expression of lipid synthesis and transport-related proteins and reduce mitochondrial related proteins, thereby increasing lipid synthesis, reducing energy consumption, and improving lipid metabolism in vivo. Silibinin can reduce lipid synthesis, increase energy consumption, and improve lipid metabolism in mice in vivo.
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Affiliation(s)
- Fei Wang
- Graduate School of Hebei Medical University, Shijiazhuang, China.,Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Shuchun Chen
- Graduate School of Hebei Medical University, Shijiazhuang, China.,Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Luping Ren
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Yichao Wang
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China.,North China University of Science and Technology, Tangshan, China
| | - Zelin Li
- Graduate School of Hebei Medical University, Shijiazhuang, China.,Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Tiantian Song
- Graduate School of Hebei Medical University, Shijiazhuang, China.,Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - He Zhang
- Graduate School of Hebei Medical University, Shijiazhuang, China.,Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Qiwen Yang
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China.,Hebei North University, Zhangjiakou, China
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5
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Basu D, Bornfeldt KE. Hypertriglyceridemia and Atherosclerosis: Using Human Research to Guide Mechanistic Studies in Animal Models. Front Endocrinol (Lausanne) 2020; 11:504. [PMID: 32849290 PMCID: PMC7423973 DOI: 10.3389/fendo.2020.00504] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 06/23/2020] [Indexed: 12/18/2022] Open
Abstract
Human studies support a strong association between hypertriglyceridemia and atherosclerotic cardiovascular disease (CVD). However, whether a causal relationship exists between hypertriglyceridemia and increased CVD risk is still unclear. One plausible explanation for the difficulty establishing a clear causal role for hypertriglyceridemia in CVD risk is that lipolysis products of triglyceride-rich lipoproteins (TRLs), rather than the TRLs themselves, are the likely mediators of increased CVD risk. This hypothesis is supported by studies of rare mutations in humans resulting in impaired clearance of such lipolysis products (remnant lipoprotein particles; RLPs). Several animal models of hypertriglyceridemia support this hypothesis and have provided additional mechanistic understanding. Mice deficient in lipoprotein lipase (LPL), the major vascular enzyme responsible for TRL lipolysis and generation of RLPs, or its endothelial anchor GPIHBP1, are severely hypertriglyceridemic but develop only minimal atherosclerosis as compared with animal models deficient in apolipoprotein (APO) E, which is required to clear TRLs and RLPs. Likewise, animal models convincingly show that increased clearance of TRLs and RLPs by LPL activation (achieved by inhibition of APOC3, ANGPTL3, or ANGPTL4 action, or increased APOA5) results in protection from atherosclerosis. Mechanistic studies suggest that RLPs are more atherogenic than large TRLs because they more readily enter the artery wall, and because they are enriched in cholesterol relative to triglycerides, which promotes pro-atherogenic effects in lesional cells. Other mechanistic studies show that hepatic receptors (LDLR and LRP1) and APOE are critical for RLP clearance. Thus, studies in animal models have provided additional mechanistic insight and generally agree with the hypothesis that RLPs derived from TRLs are highly atherogenic whereas hypertriglyceridemia due to accumulation of very large TRLs in plasma is not markedly atherogenic in the absence of TRL lipolysis products.
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Affiliation(s)
- Debapriya Basu
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY, United States
| | - Karin E. Bornfeldt
- Department of Medicine, University of Washington Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, WA, United States
- Department of Pathology, University of Washington Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, WA, United States
- *Correspondence: Karin E. Bornfeldt
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6
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Yu J, Murthy V, Liu SL. Relating GPI-Anchored Ly6 Proteins uPAR and CD59 to Viral Infection. Viruses 2019; 11:E1060. [PMID: 31739586 PMCID: PMC6893729 DOI: 10.3390/v11111060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/10/2019] [Accepted: 11/12/2019] [Indexed: 12/30/2022] Open
Abstract
The Ly6 (lymphocyte antigen-6)/uPAR (urokinase-type plasminogen activator receptor) superfamily protein is a group of molecules that share limited sequence homology but conserved three-fingered structures. Despite diverse cellular functions, such as in regulating host immunity, cell adhesion, and migration, the physiological roles of these factors in vivo remain poorly characterized. Notably, increasing research has focused on the interplays between Ly6/uPAR proteins and viral pathogens, the results of which have provided new insight into viral entry and virus-host interactions. While LY6E (lymphocyte antigen 6 family member E), one key member of the Ly6E/uPAR-family proteins, has been extensively studied, other members have not been well characterized. Here, we summarize current knowledge of Ly6/uPAR proteins related to viral infection, with a focus on uPAR and CD59. Our goal is to provide an up-to-date view of the Ly6/uPAR-family proteins and associated virus-host interaction and viral pathogenesis.
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Affiliation(s)
- Jingyou Yu
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA; (J.Y.); (V.M.)
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Vaibhav Murthy
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA; (J.Y.); (V.M.)
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Shan-Lu Liu
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA; (J.Y.); (V.M.)
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
- Viruses and Emerging Pathogens Program, Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA
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7
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Leth JM, Leth-Espensen KZ, Kristensen KK, Kumari A, Lund Winther AM, Young SG, Ploug M. Evolution and Medical Significance of LU Domain-Containing Proteins. Int J Mol Sci 2019; 20:ijms20112760. [PMID: 31195646 PMCID: PMC6600238 DOI: 10.3390/ijms20112760] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/13/2022] Open
Abstract
Proteins containing Ly6/uPAR (LU) domains exhibit very diverse biological functions and have broad taxonomic distributions in eukaryotes. In general, they adopt a characteristic three-fingered folding topology with three long loops projecting from a disulfide-rich globular core. The majority of the members of this protein domain family contain only a single LU domain, which can be secreted, glycolipid anchored, or constitute the extracellular ligand binding domain of type-I membrane proteins. Nonetheless, a few proteins contain multiple LU domains, for example, the urokinase receptor uPAR, C4.4A, and Haldisin. In the current review, we will discuss evolutionary aspects of this protein domain family with special emphasis on variations in their consensus disulfide bond patterns. Furthermore, we will present selected cases where missense mutations in LU domain-containing proteins leads to dysfunctional proteins that are causally linked to genesis of human disease.
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Affiliation(s)
- Julie Maja Leth
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Katrine Zinck Leth-Espensen
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Kristian Kølby Kristensen
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Anni Kumari
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Anne-Marie Lund Winther
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Michael Ploug
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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8
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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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9
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He C, Hu X, Jung RS, Larsson M, Tu Y, Duarte-Vogel S, Kim P, Sandoval NP, Price TR, Allan CM, Raney B, Jiang H, Bensadoun A, Walzem RL, Kuo RI, Beigneux AP, Fong LG, Young SG. Lipoprotein lipase reaches the capillary lumen in chickens despite an apparent absence of GPIHBP1. JCI Insight 2017; 2:96783. [PMID: 29046479 DOI: 10.1172/jci.insight.96783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 09/11/2017] [Indexed: 12/17/2022] Open
Abstract
In mammals, GPIHBP1 is absolutely essential for transporting lipoprotein lipase (LPL) to the lumen of capillaries, where it hydrolyzes the triglycerides in triglyceride-rich lipoproteins. In all lower vertebrate species (e.g., birds, amphibians, reptiles, fish), a gene for LPL can be found easily, but a gene for GPIHBP1 has never been found. The obvious question is whether the LPL in lower vertebrates is able to reach the capillary lumen. Using purified antibodies against chicken LPL, we showed that LPL is present on capillary endothelial cells of chicken heart and adipose tissue, colocalizing with von Willebrand factor. When the antibodies against chicken LPL were injected intravenously into chickens, they bound to LPL on the luminal surface of capillaries in heart and adipose tissue. LPL was released rapidly from chicken hearts with an infusion of heparin, consistent with LPL being located inside blood vessels. Remarkably, chicken LPL bound in a specific fashion to mammalian GPIHBP1. However, we could not identify a gene for GPIHBP1 in the chicken genome, nor could we identify a transcript for GPIHBP1 in a large chicken RNA-seq data set. We conclude that LPL reaches the capillary lumen in chickens - as it does in mammals - despite an apparent absence of GPIHBP1.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Tara R Price
- Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, Texas, USA
| | | | - Brian Raney
- University of California, Santa Cruz Genomics Institute and
| | - Haibo Jiang
- Department of Medicine and.,Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, Western Australia, Perth, Australia
| | - André Bensadoun
- Division of Nutritional Science, Cornell University, Ithaca, New York, USA
| | - Rosemary L Walzem
- Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, Texas, USA
| | - Richard I Kuo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | - Stephen G Young
- Department of Medicine and.,Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
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10
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Hebbar P, Elkum N, Alkayal F, John SE, Thanaraj TA, Alsmadi O. Genetic risk variants for metabolic traits in Arab populations. Sci Rep 2017; 7:40988. [PMID: 28106113 PMCID: PMC5247683 DOI: 10.1038/srep40988] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 12/14/2016] [Indexed: 12/11/2022] Open
Abstract
Despite a high prevalence of metabolic trait related diseases in Arabian Peninsula, there is a lack of convincingly identified genetic determinants for metabolic traits in this population. Arab populations are underrepresented in global genome-wide association studies. We genotyped 1965 unrelated Arab individuals from Kuwait using Cardio-MetaboChip, and tested SNP associations with 13 metabolic traits. Models based on recessive mode of inheritance identified Chr15:40531386-rs12440118/ZNF106/W->R as a risk variant associated with glycated-hemoglobin at close to ‘genome-wide significant’ p-value and five other risk variants ‘nominally’ associated (p-value ≤ 5.45E-07) with fasting plasma glucose (rs7144734/[OTX2-AS1,RPL3P3]) and triglyceride (rs17501809/PLGRKT; rs11143005/LOC105376072; rs900543/[THSD4,NR2E3]; and Chr12:101494770/IGF1). Furthermore, we identified 33 associations (30 SNPs with 12 traits) with ‘suggestive’ evidence of association (p-value < 1.0E-05); 20 of these operate under recessive mode of inheritance. Two of these ‘suggestive’ associations (rs1800775-CETP/HDL; and rs9326246-BUD13/TGL) showed evidence at genome-wide significance in previous studies on Euro-centric populations. Involvement of many of the identified loci in mediating metabolic traits was supported by literature evidences. The identified loci participate in critical metabolic pathways (such as Ceramide signaling, and Mitogen-Activated Protein Kinase/Extracellular Signal Regulated Kinase signaling). Data from Genotype-Tissue Expression database affirmed that 7 of the identified variants differentially regulate the up/downstream genes that mediate metabolic traits.
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Affiliation(s)
| | - Naser Elkum
- Dasman Diabetes Institute, P.O. Box 1180, Dasman 15462, Kuwait
| | - Fadi Alkayal
- Dasman Diabetes Institute, P.O. Box 1180, Dasman 15462, Kuwait
| | - Sumi Elsa John
- Dasman Diabetes Institute, P.O. Box 1180, Dasman 15462, Kuwait
| | | | - Osama Alsmadi
- Dasman Diabetes Institute, P.O. Box 1180, Dasman 15462, Kuwait
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11
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Fong LG, Young SG, Beigneux AP, Bensadoun A, Oberer M, Jiang H, Ploug M. GPIHBP1 and Plasma Triglyceride Metabolism. Trends Endocrinol Metab 2016; 27:455-469. [PMID: 27185325 PMCID: PMC4927088 DOI: 10.1016/j.tem.2016.04.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 10/21/2022]
Abstract
GPIHBP1, a GPI-anchored protein in capillary endothelial cells, is crucial for the lipolytic processing of triglyceride-rich lipoproteins (TRLs). GPIHBP1 shuttles lipoprotein lipase (LPL) to its site of action in the capillary lumen and is essential for the margination of TRLs along capillaries - such that lipolytic processing can proceed. GPIHBP1 also reduces the unfolding of the LPL catalytic domain, thereby stabilizing LPL catalytic activity. Many different GPIHBP1 mutations have been identified in patients with severe hypertriglyceridemia (chylomicronemia), the majority of which interfere with folding of the protein and abolish its capacity to bind and transport LPL. The discovery of GPIHBP1 has substantially revised our understanding of intravascular triglyceride metabolism but has also raised many new questions for future research.
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Affiliation(s)
- Loren G Fong
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
| | - Stephen G Young
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
| | - Anne P Beigneux
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - André Bensadoun
- Division of Nutritional Science, Cornell University, Ithaca, NY 14853, USA
| | - Monika Oberer
- Institute of Molecular Biosciences, University of Graz and BioTechMed, Graz, Austria
| | - Haibo Jiang
- Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 220 Copenhagen N, Denmark.
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12
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Organization, evolution and functions of the human and mouse Ly6/uPAR family genes. Hum Genomics 2016; 10:10. [PMID: 27098205 PMCID: PMC4839075 DOI: 10.1186/s40246-016-0074-2] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/14/2016] [Indexed: 01/08/2023] Open
Abstract
Members of the lymphocyte antigen-6 (Ly6)/urokinase-type plasminogen activator receptor (uPAR) superfamily of proteins are cysteine-rich proteins characterized by a distinct disulfide bridge pattern that creates the three-finger Ly6/uPAR (LU) domain. Although the Ly6/uPAR family proteins share a common structure, their expression patterns and functions vary. To date, 35 human and 61 mouse Ly6/uPAR family members have been identified. Based on their subcellular localization, these proteins are further classified as GPI-anchored on the cell membrane, or secreted. The genes encoding Ly6/uPAR family proteins are conserved across different species and are clustered in syntenic regions on human chromosomes 8, 19, 6 and 11, and mouse Chromosomes 15, 7, 17, and 9, respectively. Here, we review the human and mouse Ly6/uPAR family gene and protein structure and genomic organization, expression, functions, and evolution, and introduce new names for novel family members.
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13
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Wu M, Liu CZ, Joiner WJ. Structural Analysis and Deletion Mutagenesis Define Regions of QUIVER/SLEEPLESS that Are Responsible for Interactions with Shaker-Type Potassium Channels and Nicotinic Acetylcholine Receptors. PLoS One 2016; 11:e0148215. [PMID: 26828958 PMCID: PMC4735452 DOI: 10.1371/journal.pone.0148215] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/13/2016] [Indexed: 12/16/2022] Open
Abstract
Ly6 proteins are endogenous prototoxins found in most animals. They show striking structural and functional parallels to snake α-neurotoxins, including regulation of ion channels and cholinergic signaling. However, the structural contributions of Ly6 proteins to regulation of effector molecules is poorly understood. This question is particularly relevant to the Ly6 protein QUIVER/SLEEPLESS (QVR/SSS), which has previously been shown to suppress excitability and synaptic transmission by upregulating potassium (K) channels and downregulating nicotinic acetylcholine receptors (nAChRs) in wake-promoting neurons to facilitate sleep in Drosophila. Using deletion mutagenesis, co-immunoprecipitations, ion flux assays, surface labeling and confocal microscopy, we demonstrate that only loop 2 is required for many of the previously described properties of SSS in transfected cells, including interactions with K channels and nAChRs. Collectively our data suggest that QVR/SSS, and by extension perhaps other Ly6 proteins, target effector molecules using limited protein motifs. Mapping these motifs may be useful in rational design of drugs that mimic or suppress Ly6-effector interactions to modulate nervous system function.
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Affiliation(s)
- Meilin Wu
- Department of Pharmacology, University of California San Diego, La Jolla, California, United States of America
| | - Clifford Z Liu
- UCSD undergraduate program, Marshall College, University of California San Diego, La Jolla, California, United States of America
| | - William J Joiner
- Department of Pharmacology, University of California San Diego, La Jolla, California, United States of America.,Center for Circadian Biology, University of California San Diego, La Jolla, California, United States of America
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14
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Reimund M, Larsson M, Kovrov O, Kasvandik S, Olivecrona G, Lookene A. Evidence for Two Distinct Binding Sites for Lipoprotein Lipase on Glycosylphosphatidylinositol-anchored High Density Lipoprotein-binding Protein 1 (GPIHBP1). J Biol Chem 2015; 290:13919-34. [PMID: 25873395 DOI: 10.1074/jbc.m114.634626] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Indexed: 01/20/2023] Open
Abstract
GPIHBP1 is an endothelial membrane protein that transports lipoprotein lipase (LPL) from the subendothelial space to the luminal side of the capillary endothelium. Here, we provide evidence that two regions of GPIHBP1, the acidic N-terminal domain and the central Ly6 domain, interact with LPL as two distinct binding sites. This conclusion is based on comparative binding studies performed with a peptide corresponding to the N-terminal domain of GPIHBP1, the Ly6 domain of GPIHBP1, wild type GPIHBP1, and the Ly6 domain mutant GPIHBP1 Q114P. Although LPL and the N-terminal domain formed a tight but short lived complex, characterized by fast on- and off-rates, the complex between LPL and the Ly6 domain formed more slowly and persisted for a longer time. Unlike the interaction of LPL with the Ly6 domain, the interaction of LPL with the N-terminal domain was significantly weakened by salt. The Q114P mutant bound LPL similarly to the N-terminal domain of GPIHBP1. Heparin dissociated LPL from the N-terminal domain, and partially from wild type GPIHBP1, but was unable to elute the enzyme from the Ly6 domain. When LPL was in complex with the acidic peptide corresponding to the N-terminal domain of GPIHBP1, the enzyme retained its affinity for the Ly6 domain. Furthermore, LPL that was bound to the N-terminal domain interacted with lipoproteins, whereas LPL bound to the Ly6 domain did not. In summary, our data suggest that the two domains of GPIHBP1 interact independently with LPL and that the functionality of LPL depends on its localization on GPIHBP1.
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Affiliation(s)
- Mart Reimund
- From the Department of Chemistry, Tallinn University of Technology, Tallinn 12618, Estonia
| | - Mikael Larsson
- the Department of Medical Biosciences, Umeå University, SE-901 87 Umeå, Sweden, and
| | - Oleg Kovrov
- the Department of Medical Biosciences, Umeå University, SE-901 87 Umeå, Sweden, and
| | - Sergo Kasvandik
- the Institute of Technology, University of Tartu, Tartu 50411, Estonia
| | - Gunilla Olivecrona
- the Department of Medical Biosciences, Umeå University, SE-901 87 Umeå, Sweden, and
| | - Aivar Lookene
- From the Department of Chemistry, Tallinn University of Technology, Tallinn 12618, Estonia,
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15
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Kupferschmidt N, Csikasz RI, Ballell L, Bengtsson T, Garcia-Bennett AE. Large pore mesoporous silica induced weight loss in obese mice. Nanomedicine (Lond) 2014; 9:1353-62. [DOI: 10.2217/nnm.13.138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Background: There is a need for medical treatments to curb the rising rate of obesity. Weight reduction is correlated with a decrease in associated risk factors and cholesterol levels in humans. Amorphous silica particles have been found to exert a hypocholesterolemic effect in humans, making them popular dietary additives. Aim: To investigate the effect of mesoporous silica, which possess sharp pore size distributions, on: weight loss, cholesterol, triglycerides and glucose blood levels in obese mice. Materials & methods: Mesoporous silicas with differing pore size were mixed in the high-fat diet of obese mice. Results: Animals receiving large pore mesoporous silica with a high-fat diet show a significant reduction in body weight and fat composition, with no observable negative effects. Conclusion: Pore size is an important parameter for reduction of body weight and body fat composition by mesoporous silica, demonstrating promising signs for the treatment of obesity. Original submitted 30 January 2013; Revised submitted 20 June 2013
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Affiliation(s)
- Natalia Kupferschmidt
- Nanotechnology & Functional Materials, Department of Engineering Sciences, Uppsala University, Box 534, 751 21, Uppsala, Sweden
- Nanologica AB, Drottning Kristinasväg 62, SE 11428, Stockholm, Sweden
| | - Robert I Csikasz
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20B, 106 91, Stockholm, Sweden
| | - Lluís Ballell
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28769 Tres Cantos, Madrid, Spain
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20B, 106 91, Stockholm, Sweden
| | - Alfonso E Garcia-Bennett
- Department of Materials & Environmental Chemistry, MMK, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
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Abstract
All organisms use fatty acids (FAs) for energy substrates and as precursors for membrane and signaling lipids. The most efficient way to transport and store FAs is in the form of triglycerides (TGs); however, TGs are not capable of traversing biological membranes and therefore need to be cleaved by TG hydrolases ("lipases") before moving in or out of cells. This biochemical process is generally called "lipolysis." Intravascular lipolysis degrades lipoprotein-associated TGs to FAs for their subsequent uptake by parenchymal cells, whereas intracellular lipolysis generates FAs and glycerol for their release (in the case of white adipose tissue) or use by cells (in the case of other tissues). Although the importance of lipolysis has been recognized for decades, many of the key proteins involved in lipolysis have been uncovered only recently. Important new developments include the discovery of glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), the molecule that moves lipoprotein lipase from the interstitial spaces to the capillary lumen, and the discovery of adipose triglyceride lipase (ATGL) and comparative gene identification-58 (CGI-58) as crucial molecules in the hydrolysis of TGs within cells. This review summarizes current views of lipolysis and highlights the relevance of this process to human disease.
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Affiliation(s)
- Stephen G. Young
- Department of Medicine
- Department of Human Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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