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Yin X, Chen Y, Ruze R, Xu R, Song J, Wang C, Xu Q. The evolving view of thermogenic fat and its implications in cancer and metabolic diseases. Signal Transduct Target Ther 2022; 7:324. [PMID: 36114195 PMCID: PMC9481605 DOI: 10.1038/s41392-022-01178-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/30/2022] [Accepted: 09/05/2022] [Indexed: 02/07/2023] Open
Abstract
AbstractThe incidence of metabolism-related diseases like obesity and type 2 diabetes mellitus has reached pandemic levels worldwide and increased gradually. Most of them are listed on the table of high-risk factors for malignancy, and metabolic disorders systematically or locally contribute to cancer progression and poor prognosis of patients. Importantly, adipose tissue is fundamental to the occurrence and development of these metabolic disorders. White adipose tissue stores excessive energy, while thermogenic fat including brown and beige adipose tissue dissipates energy to generate heat. In addition to thermogenesis, beige and brown adipocytes also function as dynamic secretory cells and a metabolic sink of nutrients, like glucose, fatty acids, and amino acids. Accordingly, strategies that activate and expand thermogenic adipose tissue offer therapeutic promise to combat overweight, diabetes, and other metabolic disorders through increasing energy expenditure and enhancing glucose tolerance. With a better understanding of its origins and biological functions and the advances in imaging techniques detecting thermogenesis, the roles of thermogenic adipose tissue in tumors have been revealed gradually. On the one hand, enhanced browning of subcutaneous fatty tissue results in weight loss and cancer-associated cachexia. On the other hand, locally activated thermogenic adipocytes in the tumor microenvironment accelerate cancer progression by offering fuel sources and is likely to develop resistance to chemotherapy. Here, we enumerate current knowledge about the significant advances made in the origin and physiological functions of thermogenic fat. In addition, we discuss the multiple roles of thermogenic adipocytes in different tumors. Ultimately, we summarize imaging technologies for identifying thermogenic adipose tissue and pharmacologic agents via modulating thermogenesis in preclinical experiments and clinical trials.
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Liu S, Wang Z, Zheng X, Zhang Y, Wei S, OuYang H, Liang J, Chen N, Zeng W, Jiang J. Case Report: Successful Management of a 29-Day-Old Infant With Severe Hyperlipidemia From a Novel Homozygous Variant of GPIHBP1 Gene. Front Pediatr 2022; 10:792574. [PMID: 35359903 PMCID: PMC8960264 DOI: 10.3389/fped.2022.792574] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 02/03/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Severe hyperlipidemia is characterized by markedly elevated blood triglyceride levels and severe early-onset cardiovascular diseases, pancreatitis, pancreatic necrosis or persistent multiple organ failure if left untreated. It is a rare autosomal recessive metabolic disorder originated from the variants of lipoprotein lipase gene, and previous studies have demonstrated that most cases with severe hyperlipidemia are closely related to the variants of some key genes for lipolysis, such as LPL, APOC2, APOA5, LMF1, and GPIHBP1. Meanwhile, other unidentified causes also exist and are equally worthy of attention. METHODS The 29-day-old infant was diagnosed with severe hyperlipidemia, registering a plasma triglyceride level as high as 25.46 mmol/L. Whole exome sequencing was conducted to explore the possible pathogenic gene variants for this patient. RESULTS The infant was put on a low-fat diet combined with pharmacological therapy, which was successful in restraining the level of serum triglyceride and total cholesterol to a low to medium range during the follow-ups. The patient was found to be a rare novel homozygous duplication variant-c.45_48dupGCGG (Pro17Alafs*22) in GPIHBP1 gene-leading to a frameshift which failed to form the canonical termination codon TGA. The mutant messenger RNA should presumably produce a peptide consisting of 16 amino acids at the N-terminus, with 21 novel amino acids on the heels of the wild-type protein. CONCLUSIONS Our study expands on the spectrum of GPIHBP1 variants and contributes to a more comprehensive understanding of the genetic diagnosis, genetic counseling, and multimodality therapy of families with severe hyperlipidemia. Our experience gained in this study is also contributory to a deeper insight into severe hyperlipidemia and highlights the importance of molecular genetic tests.
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Affiliation(s)
- Shu Liu
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Zhiqing Wang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xianhua Zheng
- Department of Clinical Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Ye Zhang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Sisi Wei
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Haimei OuYang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jinqun Liang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Nuan Chen
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Weihong Zeng
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jianhui Jiang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
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Fischer AW, Jaeckstein MY, Gottschling K, Heine M, Sass F, Mangels N, Schlein C, Worthmann A, Bruns OT, Yuan Y, Zhu H, Chen O, Ittrich H, Nilsson SK, Stefanicka P, Ukropec J, Balaz M, Dong H, Sun W, Reimer R, Scheja L, Heeren J. Lysosomal lipoprotein processing in endothelial cells stimulates adipose tissue thermogenic adaptation. Cell Metab 2021; 33:547-564.e7. [PMID: 33357458 DOI: 10.1016/j.cmet.2020.12.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 10/02/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022]
Abstract
In response to cold exposure, thermogenic adipocytes internalize large amounts of fatty acids after lipoprotein lipase-mediated hydrolysis of triglyceride-rich lipoproteins (TRL) in the capillary lumen of brown adipose tissue (BAT) and white adipose tissue (WAT). Here, we show that in cold-exposed mice, vascular endothelial cells in adipose tissues endocytose substantial amounts of entire TRL particles. These lipoproteins subsequently follow the endosomal-lysosomal pathway, where they undergo lysosomal acid lipase (LAL)-mediated processing. Endothelial cell-specific LAL deficiency results in impaired thermogenic capacity as a consequence of reduced recruitment of brown and brite/beige adipocytes. Mechanistically, TRL processing by LAL induces proliferation of endothelial cells and adipocyte precursors via beta-oxidation-dependent production of reactive oxygen species, which in turn stimulates hypoxia-inducible factor-1α-dependent proliferative responses. In conclusion, this study demonstrates a physiological role for TRL particle uptake into BAT and WAT and establishes endothelial lipoprotein processing as an important determinant of adipose tissue remodeling during thermogenic adaptation.
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Affiliation(s)
- Alexander W Fischer
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Michelle Y Jaeckstein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kristina Gottschling
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Markus Heine
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Frederike Sass
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nils Mangels
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Schlein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anna Worthmann
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Oliver T Bruns
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Neuherberg, Germany
| | - Yucheng Yuan
- Department of Chemistry, Brown University, Providence, RI, USA
| | - Hua Zhu
- Department of Chemistry, Brown University, Providence, RI, USA
| | - Ou Chen
- Department of Chemistry, Brown University, Providence, RI, USA
| | - Harald Ittrich
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan K Nilsson
- Department of Medical Biosciences, Umeå University, Umeå, Sweden
| | - Patrik Stefanicka
- Department of Otorhinolaryngology - Head and Neck Surgery, Comenius University, Bratislava, Slovakia
| | - Jozef Ukropec
- Institute of Experimental Endocrinology, Biomedical Research Center at the Slovak Academy of Sciences, Bratislava, Slovakia
| | - Miroslav Balaz
- Institute of Food, Nutrition and Health, ETH Zürich, Schwerzenbach, Switzerland
| | - Hua Dong
- Institute of Food, Nutrition and Health, ETH Zürich, Schwerzenbach, Switzerland
| | - Wenfei Sun
- Institute of Food, Nutrition and Health, ETH Zürich, Schwerzenbach, Switzerland
| | - Rudolf Reimer
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Chen YQ, Pottanat TG, Siegel RW, Ehsani M, Qian YW, Roell WC, Konrad RJ. Angiopoietin-like protein 4(E40K) and ANGPTL4/8 complex have reduced, temperature-dependent LPL-inhibitory activity compared to ANGPTL4. Biochem Biophys Res Commun 2020; 534:498-503. [PMID: 33239171 DOI: 10.1016/j.bbrc.2020.11.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/12/2020] [Indexed: 12/13/2022]
Abstract
We previously demonstrated that angiopoietin-like 8 (ANGPTL8) forms a localized complex with ANGPTL4 to reduce its lipoprotein lipase (LPL)-inhibitory activity and enable increased postprandial uptake of fatty acids (FA) into adipose tissue. Because prolonged cold exposure may increase adipose tissue FA uptake and decrease circulating triglycerides (TG) by reducing ANGPTL4 expression and inducing ANGPTL8 expression (and thus ANGPTL4/8 expression), we investigated the effect of temperature on ANGPTL4 and ANGPTL4/8 LPL-inhibitory activities in vitro. As the ANGPTL4(E40K) mutation results in decreased TG, we also characterized ANGPTL4(E40K) and ANGPTL4(E40K)/8 complex LPL-inhibitory activities. Interestingly, while ANGPTL3, ANGPTL3/8, and ANGPTL4 showed similar LPL inhibition at 37 °C and 22 °C, the already reduced LPL-inhibitory activity of ANGPTL4/8 at 37 °C was even more decreased at 22 °C. At 37 °C, ANGPTL4(E40K) manifested decreased LPL-inhibitory activity compared to ANGPTL4/8, while ANGPTL4(E40K)/8 had even further reduced potency. Remarkably, ANGPTL4/8, ANGPTL4(E40K), and ANGPTL4(E40K)/8 were each actually capable of stimulating LPL activity at 22 °C. Together, these results indicate that ANGPTL4/8 stimulation of LPL activity at low temperatures may represent an additional mechanism for further increasing adipose tissue FA uptake during cold exposure, beyond that already occurring due to decreased ANGPTL4 expression and increased ANGPTL8 expression. In addition, because ANGPTL4(E40K) has decreased LPL-inhibitory activity compared to ANGPTL4/8, our findings also suggest why ANGPTL4(E40K) carriers have decreased circulating TG levels.
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Affiliation(s)
- Yan Q Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Thomas G Pottanat
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA; Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA
| | - Robert W Siegel
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Mariam Ehsani
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Yue-Wei Qian
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - William C Roell
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
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Przygodda F, Lautherbach N, Buzelle SL, Goncalves DA, Assis AP, Paula-Gomes S, Garófalo MAR, Heck LC, Matsuo FS, Mota RF, Osako MK, Kettelhut IC, Navegantes LC. Sympathetic innervation suppresses the autophagic-lysosomal system in brown adipose tissue under basal and cold-stimulated conditions. J Appl Physiol (1985) 2020; 128:855-871. [PMID: 32027543 DOI: 10.1152/japplphysiol.00065.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The sympathetic nervous system (SNS) activates cAMP signaling and promotes trophic effects on brown adipose tissue (BAT) through poorly understood mechanisms. Because norepinephrine has been found to induce antiproteolytic effects on muscle and heart, we hypothesized that the SNS could inhibit autophagy in interscapular BAT (IBAT). Here, we describe that selective sympathetic denervation of rat IBAT kept at 25°C induced atrophy, and in parallel dephosphorylated forkhead box class O (FoxO), and increased cathepsin activity, autophagic flux, autophagosome formation, and expression of autophagy-related genes. Conversely, cold stimulus (4°C) for up to 72 h induced thermogenesis and IBAT hypertrophy, an anabolic effect that was associated with inhibition of cathepsin activity, autophagic flux, and autophagosome formation. These effects were abrogated by sympathetic denervation, which also upregulated Gabarapl1 mRNA. In addition, the cold-driven sympathetic activation stimulated the mechanistic target of rapamycin (mTOR) pathway, leading to the enhancement of protein synthesis, evaluated in vivo by puromycin incorporation, and to the inhibitory phosphorylation of Unc51-like kinase-1, a key protein in the initiation of autophagy. This coincided with a higher content of exchange protein-1 directly activated by cAMP (Epac1), a cAMP effector, and phosphorylation of Akt at Thr308, all these effects being abolished by denervation. Systemic treatment with norepinephrine for 72 h mimicked most of the cold effects on IBAT. These data suggest that the noradrenergic sympathetic inputs to IBAT restrain basal autophagy via suppression of FoxO and, in the setting of cold, stimulate protein synthesis via the Epac/Akt/mTOR-dependent pathway and suppress the autophagosome formation, probably through posttranscriptional mechanisms.NEW & NOTEWORTHY The underlying mechanisms related to the anabolic role of sympathetic innervation on brown adipose tissue (BAT) are unclear. We show that sympathetic denervation activates autophagic-lysosomal degradation, leading to a loss of mitochondrial proteins and BAT atrophy. Conversely, cold-driven sympathetic activation suppresses autophagy and stimulates protein synthesis, leading to BAT hypertrophy. Given its high-potential capacity for heat production, understanding the mechanisms that contribute to BAT mass is important to optimize chances of survival for endotherms in cold ambients.
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Affiliation(s)
- Franciele Przygodda
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Natalia Lautherbach
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Samyra Lopes Buzelle
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Dawit Albieiro Goncalves
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.,Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Ana Paula Assis
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Sílvia Paula-Gomes
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Lilian Carmo Heck
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Flávia Sayuri Matsuo
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Ryerson Fonseca Mota
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Mariana Kiomy Osako
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Isis C Kettelhut
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luiz C Navegantes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Guo C, Zhao Z, Deng X, Chen Z, Tu Z, Yuan G. Regulation of angiopoietin-like protein 8 expression under different nutritional and metabolic status. Endocr J 2019; 66:1039-1046. [PMID: 31631098 DOI: 10.1507/endocrj.ej19-0263] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with increasing prevalence worldwide. Angiopoietin-like protein 8 (ANGPTL8), a member of the angiopoietin-like protein family, is involved in glucose metabolism, lipid metabolism, and energy homeostasis and believed to be associated with T2DM. Expression levels of ANGPTL8 are often significantly altered in metabolic diseases, such as non-alcoholic fatty liver disease (NAFLD) and diabetes mellitus. Studies have shown that ANGPTL8, together with other members of this protein family, such as angiopoietin-like protein 3 (ANGPTL3) and angiopoietin-like protein 4 (ANGPTL4), regulates the activity of lipoprotein lipase (LPL), thereby participating in the regulation of triglyceride related lipoproteins (TRLs). In addition, members of the angiopoietin-like protein family are varyingly expressed among different tissues and respond differently under diverse nutritional and metabolic status. These findings may provide new options for the diagnosis and treatment of diabetes, metabolic syndromes and other diseases. In this review, the interaction between ANGPTL8 and ANGPTL3 or ANGPTL4, and the differential expression of ANGPTL8 responding to different nutritional and metabolic status during the regulation of LPL activity were reviewed.
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Affiliation(s)
- Chang Guo
- Department of Endocrinology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212001, China
| | - Zhicong Zhao
- Department of Endocrinology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212001, China
| | - Xia Deng
- Department of Endocrinology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212001, China
| | - Zian Chen
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Zhigang Tu
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Guoyue Yuan
- Department of Endocrinology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212001, China
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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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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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