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Foster C, Gagnon CA, Ashraf AP. Altered lipid metabolism and the development of metabolic-associated fatty liver disease. Curr Opin Lipidol 2024; 35:200-207. [PMID: 38484227 DOI: 10.1097/mol.0000000000000933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
PURPOSE OF REVIEW An increasing amount of research has underscored the significant role of lipoproteins in the pathogenesis of metabolic-associated fatty liver disease (MAFLD). This comprehensive review examines the intricate relationship between lipoprotein abnormalities and the development of MAFLD. RECENT FINDINGS Atherogenic dyslipidemia seen in insulin resistance states play a significant role in initiating and exacerbating hepatic lipid accumulation. There are also specific genetic factors ( PNPLA3 , TM6SF2 , MBOAT7 , HSD17B13 , GCKR- P446L) and transcription factors (SREBP-2, FXR, and LXR9) that increase susceptibility to both lipoprotein disorders and MAFLD. Most monogenic primary lipid disorders do not cause hepatic steatosis unless accompanied by metabolic stress. Hepatic steatosis occurs in the presence of secondary systemic metabolic stress in conjunction with predisposing environmental factors that lead to insulin resistance. Identifying specific aberrant lipoprotein metabolic factors promoting hepatic fat accumulation and subsequently exacerbating steatohepatitis will shed light on potential targets for therapeutic interventions. SUMMARY The clinical implications of interconnection between genetic factors and an insulin resistant environment that predisposes MAFLD is many fold. Potential therapeutic strategies in preventing or mitigating MAFLD progression include lifestyle modifications, pharmacological interventions, and emerging therapies targeting aberrant lipoprotein metabolism.
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Affiliation(s)
- Christy Foster
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Alabama at Birmingham
| | - Charles A Gagnon
- University of Alabama at Birmingham Marnix E. Heersink School of Medicine, Birmingham, Alabama, USA
| | - Ambika P Ashraf
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Alabama at Birmingham
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2
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Smati S, Wargny M, Boursier J, Moulin P, Di Filippo M, Cariou B. Prevalence of Liver Steatosis and Fibrosis in Adults With Primary Hypobetaliproteinemia: Results From the HYPOCHOL Study. Clin Gastroenterol Hepatol 2024:S1542-3565(24)00606-2. [PMID: 38971410 DOI: 10.1016/j.cgh.2024.06.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 06/02/2024] [Accepted: 06/21/2024] [Indexed: 07/08/2024]
Affiliation(s)
- Sarra Smati
- Nantes Université, CHU Nantes, CNRS, Inserm, L'institut du Thorax, Nantes, France; CHU Nantes, Inserm, CIC 1413, L'institut du Thorax, Nantes, France
| | - Matthieu Wargny
- Nantes Université, CHU Nantes, CNRS, Inserm, L'institut du Thorax, Nantes, France; CHU Nantes, Inserm, CIC 1413, L'institut du Thorax, Nantes, France; Nantes Université, CHU Nantes, Pôle Hospitalo-Universitaire 11: Santé Publique, Clinique des Données, INSERM, CIC 1413, Nantes, France
| | - Jerome Boursier
- Service d'Hépato-Gastroentérologie et Oncologie Digestive, Hôpital Universitaire d'Angers, Angers, France; Laboratoire HIFIH, SFR ICAT 4208, Université d'Angers, Angers, France
| | - Philippe Moulin
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France; Fédération d'Endocrinologie, Maladies Métaboliques, Diabète, et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Mathilde Di Filippo
- Fédération d'Endocrinologie, Maladies Métaboliques, Diabète, et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France; UF Dyslipidémies, Service de Biochimie et de Biologie Moléculaire, Laboratoire de Biologie Médicale MultiStites, Hospices Civils de Lyon, Bron, France
| | - Bertrand Cariou
- Nantes Université, CHU Nantes, CNRS, Inserm, L'institut du Thorax, Nantes, France; CHU Nantes, Inserm, CIC 1413, L'institut du Thorax, Nantes, France.
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3
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Burks KH, Xie Y, Gildea M, Jung IH, Mukherjee S, Lee P, Pudupakkam U, Wagoner R, Patel V, Santana K, Alisio A, Goldberg IJ, Finck BN, Fisher EA, Davidson NO, Stitziel NO. ANGPTL3 deficiency impairs lipoprotein production and produces adaptive changes in hepatic lipid metabolism. J Lipid Res 2024; 65:100500. [PMID: 38219820 PMCID: PMC10875267 DOI: 10.1016/j.jlr.2024.100500] [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: 05/22/2023] [Revised: 12/22/2023] [Accepted: 12/23/2023] [Indexed: 01/16/2024] Open
Abstract
Angiopoietin-like protein 3 (ANGPTL3) is a hepatically secreted protein and therapeutic target for reducing plasma triglyceride-rich lipoproteins and low-density lipoprotein (LDL) cholesterol. Although ANGPTL3 modulates the metabolism of circulating lipoproteins, its role in triglyceride-rich lipoprotein assembly and secretion remains unknown. CRISPR-associated protein 9 (CRISPR/Cas9) was used to target ANGPTL3 in HepG2 cells (ANGPTL3-/-) whereupon we observed ∼50% reduction of apolipoprotein B100 (ApoB100) secretion, accompanied by an increase in ApoB100 early presecretory degradation via a predominantly lysosomal mechanism. Despite defective particle secretion in ANGPTL3-/- cells, targeted lipidomic analysis did not reveal neutral lipid accumulation in ANGPTL3-/- cells; rather ANGPTL3-/- cells demonstrated decreased secretion of newly synthesized triglycerides and increased fatty acid oxidation. Furthermore, RNA sequencing demonstrated significantly altered expression of key lipid metabolism genes, including targets of peroxisome proliferator-activated receptor α, consistent with decreased lipid anabolism and increased lipid catabolism. In contrast, CRISPR/Cas9 LDL receptor (LDLR) deletion in ANGPTL3-/- cells did not result in a secretion defect at baseline, but proteasomal inhibition strongly induced compensatory late presecretory degradation of ApoB100 and impaired its secretion. Additionally, these ANGPTL3-/-;LDLR-/- cells rescued the deficient LDL clearance of LDLR-/- cells. In summary, ANGPTL3 deficiency in the presence of functional LDLR leads to the production of fewer lipoprotein particles due to early presecretory defects in particle assembly that are associated with adaptive changes in intrahepatic lipid metabolism. In contrast, when LDLR is absent, ANGPTL3 deficiency is associated with late presecretory regulation of ApoB100 degradation without impaired secretion. Our findings therefore suggest an unanticipated intrahepatic role for ANGPTL3, whose function varies with LDLR status.
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Affiliation(s)
- Kendall H Burks
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Yan Xie
- Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, USA
| | - Michael Gildea
- Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - In-Hyuk Jung
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Sandip Mukherjee
- Division of Nutritional Science and Obesity Medicine, Department of Medicine, Center for Human Nutrition, Washington University School of Medicine, Saint Louis, MO, USA
| | - Paul Lee
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Upasana Pudupakkam
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Ryan Wagoner
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Ved Patel
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Katherine Santana
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Arturo Alisio
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Ira J Goldberg
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Brian N Finck
- Division of Nutritional Science and Obesity Medicine, Department of Medicine, Center for Human Nutrition, Washington University School of Medicine, Saint Louis, MO, USA
| | - Edward A Fisher
- Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Nicholas O Davidson
- Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, USA.
| | - Nathan O Stitziel
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA; Department of Genetics, Washington University School of Medicine, Saint Louis, MO, USA.
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4
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Chen Z, Wang S, Pottekat A, Duffey A, Jang I, Chang BH, Cho J, Finck BN, Davidson NO, Kaufman RJ. Conditional hepatocyte ablation of PDIA1 uncovers indispensable roles in both APOB and MTTP folding to support VLDL secretion. Mol Metab 2024; 80:101874. [PMID: 38211723 PMCID: PMC10832468 DOI: 10.1016/j.molmet.2024.101874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/04/2024] [Accepted: 01/06/2024] [Indexed: 01/13/2024] Open
Abstract
OBJECTIVES The assembly and secretion of hepatic very low-density lipoprotein (VLDL) plays pivotal roles in hepatic and plasma lipid homeostasis. Protein disulfide isomerase A1 (PDIA1/P4HB) is a molecular chaperone whose functions are essential for protein folding in the endoplasmic reticulum. Here we investigated the physiological requirement in vivo for PDIA1 in maintaining VLDL assembly and secretion. METHODS Pdia1/P4hb was conditionally deleted in adult mouse hepatocytes and the phenotypes characterized. Mechanistic analyses in primary hepatocytes determined how PDIA1 ablation alters MTTP synthesis and degradation as well as altering synthesis and secretion of Apolipoprotein B (APOB), along with complementary expression of intact PDIA1 vs a catalytically inactivated PDIA1 mutant. RESULTS Hepatocyte-specific deletion of Pdia1/P4hb inhibited hepatic MTTP expression and dramatically reduced VLDL production, leading to severe hepatic steatosis and hypolipidemia. Pdia1-deletion did not affect mRNA expression or protein stability of MTTP but rather prevented Mttp mRNA translation. We demonstrate an essential role for PDIA1 in MTTP synthesis and function and show that PDIA1 interacts with APOB in an MTTP-independent manner via its molecular chaperone function to support APOB folding and secretion. CONCLUSIONS PDIA1 plays indispensable roles in APOB folding, MTTP synthesis and activity to support VLDL assembly. Thus, like APOB and MTTP, PDIA1 is an obligatory component of hepatic VLDL production.
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Affiliation(s)
- Zhouji Chen
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA.
| | - Shiyu Wang
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Anita Pottekat
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Alec Duffey
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Insook Jang
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Benny H Chang
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jaehyung Cho
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Brian N Finck
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nicholas O Davidson
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Randal J Kaufman
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA.
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Srivastava RAK. A Review of Progress on Targeting LDL Receptor-Dependent and -Independent Pathways for the Treatment of Hypercholesterolemia, a Major Risk Factor of ASCVD. Cells 2023; 12:1648. [PMID: 37371118 DOI: 10.3390/cells12121648] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
Since the discovery of the LDL receptor in 1973 by Brown and Goldstein as a causative protein in hypercholesterolemia, tremendous amounts of effort have gone into finding ways to manage high LDL cholesterol in familial hypercholesterolemic (HoFH and HeFH) individuals with loss-of-function mutations in the LDL receptor (LDLR) gene. Statins proved to be the first blockbuster drug, helping both HoFH and HeFH individuals by inhibiting the cholesterol synthesis pathway rate-limiting enzyme HMG-CoA reductase and inducing the LDL receptor. However, statins could not achieve the therapeutic goal of LDL. Other therapies targeting LDLR include PCSK9, which lowers LDLR by promoting LDLR degradation. Inducible degrader of LDLR (IDOL) also controls the LDLR protein, but an IDOL-based therapy is yet to be developed. Among the LDLR-independent pathways, such as angiopoietin-like 3 (ANGPTL3), apolipoprotein (apo) B, apoC-III and CETP, only ANGPTL3 offers the advantage of treating both HoFH and HeFH patients and showing relatively better preclinical and clinical efficacy in animal models and hypercholesterolemic individuals, respectively. While loss-of-LDLR-function mutations have been known for decades, gain-of-LDLR-function mutations have recently been identified in some individuals. The new information on gain of LDLR function, together with CRISPR-Cas9 genome/base editing technology to target LDLR and ANGPTL3, offers promise to HoFH and HeFH individuals who are at a higher risk of developing atherosclerotic cardiovascular disease (ASCVD).
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Affiliation(s)
- Rai Ajit K Srivastava
- Integrated Pharma Solutions LLC, Boston, MA 02101-02117, USA
- College of Professional Studies, Northeastern University, Boston, MA 02101-02117, USA
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6
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Lin Y, Lu K, Yu S, Cai T, Zitnik M. Multimodal learning on graphs for disease relation extraction. J Biomed Inform 2023:104415. [PMID: 37276949 DOI: 10.1016/j.jbi.2023.104415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 02/24/2023] [Accepted: 05/30/2023] [Indexed: 06/07/2023]
Abstract
OBJECTIVE Disease knowledge graphs have emerged as a powerful tool for AI, enabling the connection, organization, and access to diverse information about diseases. However, the relations between disease concepts are often distributed across multiple data formats, including plain language and incomplete disease knowledge graphs. As a result, extracting disease relations from multimodal data sources is crucial for constructing accurate and comprehensive disease knowledge graphs. METHODS We introduce REMAP, a multimodal approach for disease relation extraction. The REMAP machine learning approach jointly embeds a partial, incomplete knowledge graph and a medical language dataset into a compact latent vector space, aligning the multimodal embeddings for optimal disease relation extraction. Additionally, REMAP utilizes a decoupled model structure to enable inference in single-modal data, which can be applied under missing modality scenarios. RESULTS We apply the REMAP approach to a disease knowledge graph with 96,913 relations and a text dataset of 1.24 million sentences. On a dataset annotated by human experts, REMAP improves language-based disease relation extraction by 10.0% (accuracy) and 17.2% (F1-score) by fusing disease knowledge graphs with language information. Furthermore, REMAP leverages text information to recommend new relationships in the knowledge graph, outperforming graph-based methods by 8.4% (accuracy) and 10.4% (F1-score). CONCLUSION In summary, REMAP is a flexible multimodal approach for extracting disease relations by fusing structured knowledge and language information. This approach provides a powerful model to easily find, access, and evaluate relations between disease concepts.
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Affiliation(s)
- Yucong Lin
- Institute of Engineering Medicine, Beijing Institute of Technology, Beijing, China; Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing, China
| | - Keming Lu
- Viterbi School of Engineering, University of Southern California, Los Angeles, CA, 90007, USA
| | - Sheng Yu
- Center for Statistical Science, Tsinghua University, Beijing, China; Department of Industrial Engineering, Tsinghua University, Beijing, China
| | - Tianxi Cai
- Department of Biostatistics, Harvard T.H.Chan School of Public Health, Boston, MA, 02115, USA; Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Marinka Zitnik
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA; Broad Institute of MIT and Harvard, Boston, MA, 02142, USA; Harvard Data Science Initiative, Cambridge, MA, 02138, USA.
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7
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Fatima M, Karwasra R, Almalki WH, Sahebkar A, Kesharwani P. Galactose engineered nanocarriers: Hopes and hypes in cancer therapy. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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8
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Metz M, Beghini M, Wolf P, Pfleger L, Hackl M, Bastian M, Freudenthaler A, Harreiter J, Zeyda M, Baumgartner-Parzer S, Marculescu R, Marella N, Hannich JT, Györi G, Berlakovich G, Roden M, Krebs M, Risti R, Lõokene A, Trauner M, Kautzky-Willer A, Krššák M, Stangl H, Fürnsinn C, Scherer T. Leptin increases hepatic triglyceride export via a vagal mechanism in humans. Cell Metab 2022; 34:1719-1731.e5. [PMID: 36220067 DOI: 10.1016/j.cmet.2022.09.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 08/08/2022] [Accepted: 09/20/2022] [Indexed: 01/11/2023]
Abstract
Recombinant human leptin (metreleptin) reduces hepatic lipid content in patients with lipodystrophy and overweight patients with non-alcoholic fatty liver disease and relative hypoleptinemia independent of its anorexic action. In rodents, leptin signaling in the brain increases very-low-density lipoprotein triglyceride (VLDL-TG) secretion and reduces hepatic lipid content via the vagus nerve. In this randomized, placebo-controlled crossover trial (EudraCT Nr. 2017-003014-22), we tested whether a comparable mechanism regulates hepatic lipid metabolism in humans. A single metreleptin injection stimulated hepatic VLDL-TG secretion (primary outcome) and reduced hepatic lipid content in fasted, lean men (n = 13, age range 20-38 years) but failed to do so in metabolically healthy liver transplant recipients (n = 9, age range 26-62 years) who represent a model for hepatic denervation. In an independent cohort of lean men (n = 10, age range 23-31 years), vagal stimulation by modified sham feeding replicated the effects of metreleptin on VLDL-TG secretion. Therefore, we propose that leptin has anti-steatotic properties that are independent of food intake by stimulating hepatic VLDL-TG export via a brain-vagus-liver axis.
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Affiliation(s)
- Matthäus Metz
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Marianna Beghini
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Peter Wolf
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Lorenz Pfleger
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Martina Hackl
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Magdalena Bastian
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Angelika Freudenthaler
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Jürgen Harreiter
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Maximilian Zeyda
- Clinical Division of Pediatric Pulmonology, Allergology and Endocrinology, Department for Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna 1090, Austria
| | - Sabina Baumgartner-Parzer
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Rodrig Marculescu
- Department of Laboratory Medicine, Medical University of Vienna, Vienna 1090, Austria
| | - Nara Marella
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna 1090, Austria
| | - J Thomas Hannich
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna 1090, Austria
| | - Georg Györi
- Division of Transplantation, Department of Surgery, Medical University of Vienna, Vienna 1090, Austria
| | - Gabriela Berlakovich
- Division of Transplantation, Department of Surgery, Medical University of Vienna, Vienna 1090, Austria
| | - Michael Roden
- Division of Endocrinology and Diabetology, Medical Faculty and University Hospital, Heinrich Heine University, Düsseldorf 40225, Germany; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf 40225, Germany
| | - Michael Krebs
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Robert Risti
- Department of Chemistry, Tallinn University of Technology, Tallinn 12618, Estonia
| | - Aivar Lõokene
- Department of Chemistry, Tallinn University of Technology, Tallinn 12618, Estonia
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Alexandra Kautzky-Willer
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Martin Krššák
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Herbert Stangl
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna 1090, Austria
| | - Clemens Fürnsinn
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Thomas Scherer
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria.
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Haas ME, Pirruccello JP, Friedman SN, Wang M, Emdin CA, Ajmera VH, Simon TG, Homburger JR, Guo X, Budoff M, Corey KE, Zhou AY, Philippakis A, Ellinor PT, Loomba R, Batra P, Khera AV. Machine learning enables new insights into genetic contributions to liver fat accumulation. CELL GENOMICS 2021; 1:100066. [PMID: 34957434 PMCID: PMC8699145 DOI: 10.1016/j.xgen.2021.100066] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Excess liver fat, called hepatic steatosis, is a leading risk factor for end-stage liver disease and cardiometabolic diseases but often remains undiagnosed in clinical practice because of the need for direct imaging assessments. We developed an abdominal MRI-based machine-learning algorithm to accurately estimate liver fat (correlation coefficients, 0.97-0.99) from a truth dataset of 4,511 middle-aged UK Biobank participants, enabling quantification in 32,192 additional individuals. 17% of participants had predicted liver fat levels indicative of steatosis, and liver fat could not have been reliably estimated based on clinical factors such as BMI. A genome-wide association study of common genetic variants and liver fat replicated three known associations and identified five newly associated variants in or near the MTARC1, ADH1B, TRIB1, GPAM, and MAST3 genes (p < 3 × 10-8). A polygenic score integrating these eight genetic variants was strongly associated with future risk of chronic liver disease (hazard ratio > 1.32 per SD score, p < 9 × 10-17). Rare inactivating variants in the APOB or MTTP genes were identified in 0.8% of individuals with steatosis and conferred more than 6-fold risk (p < 2 × 10-5), highlighting a molecular subtype of hepatic steatosis characterized by defective secretion of apolipoprotein B-containing lipoproteins. We demonstrate that our imaging-based machine-learning model accurately estimates liver fat and may be useful in epidemiological and genetic studies of hepatic steatosis.
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Affiliation(s)
- Mary E. Haas
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Department of Molecular Biology, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - James P. Pirruccello
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Department of Medicine, Harvard Medical School, Boston, MA 02114, USA,Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Machine Learning for Health, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Samuel N. Friedman
- Machine Learning for Health, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Minxian Wang
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Connor A. Emdin
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Veeral H. Ajmera
- NAFLD Research Center, Department of Medicine, University of California San Diego, La Jolla, CA 92103, USA
| | - Tracey G. Simon
- Department of Medicine, Harvard Medical School, Boston, MA 02114, USA,Liver Center, Division of Gastroenterology, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Xiuqing Guo
- The Lundquist Institute for Biomedical Innovation and Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Matthew Budoff
- The Lundquist Institute for Biomedical Innovation and Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Kathleen E. Corey
- Department of Medicine, Harvard Medical School, Boston, MA 02114, USA,Liver Center, Division of Gastroenterology, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Anthony Philippakis
- Machine Learning for Health, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Eric and Wendy Schmidt Center, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Patrick T. Ellinor
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Department of Medicine, Harvard Medical School, Boston, MA 02114, USA,Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Machine Learning for Health, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Rohit Loomba
- NAFLD Research Center, Department of Medicine, University of California San Diego, La Jolla, CA 92103, USA
| | - Puneet Batra
- Machine Learning for Health, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Amit V. Khera
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Center for Genomic Medicine, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Medicine, Harvard Medical School, Boston, MA 02114, USA,Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Machine Learning for Health, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Corresponding author
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10
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Domenech M, Llano-Rivas I, Arroyo V, Ortega E. Novel APOB mutation in familial hypobetalipoproteinemia. J Clin Lipidol 2021; 16:28-32. [PMID: 34852964 DOI: 10.1016/j.jacl.2021.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 10/19/2022]
Affiliation(s)
- M Domenech
- Lipid and Vascular Risk Unit, Endocrinology and Nutrition Department, Hospital Clinic of Barcelona, Spain; Faculty of Medicine and Health Sciences. University of Barcelona. Spain; Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBEROBN). Institute of Health Carlos III, ISCIII. Spain
| | - Isabel Llano-Rivas
- Clinical Genetics, Genetic Service. Hospital Universitario Cruces, Basque Country, Spain
| | - Vicente Arroyo
- EF Clif, EASL-CLIF Consortium and Grifols Chair, Barcelona, Spain
| | - Emilio Ortega
- Lipid and Vascular Risk Unit, Endocrinology and Nutrition Department, Hospital Clinic of Barcelona, Spain; Faculty of Medicine and Health Sciences. University of Barcelona. Spain; Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBEROBN). Institute of Health Carlos III, ISCIII. Spain.
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11
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Jay PY, Maier MA, Saltonstall L, Duarte L, Antonino I, Vest J. Gene Silencing Therapeutics in Cardiology: A Review Article. INTERNATIONAL JOURNAL OF CARDIOVASCULAR SCIENCES 2021. [DOI: 10.36660/ijcs.20200306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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12
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Vilar-Gomez E, Gawrieh S, Liang T, McIntyre AD, Hegele RA, Chalasani N. Interrogation of selected genes influencing serum LDL-Cholesterol levels in patients with well characterized NAFLD. J Clin Lipidol 2021; 15:275-291. [PMID: 33454241 PMCID: PMC8187295 DOI: 10.1016/j.jacl.2020.12.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 12/07/2020] [Accepted: 12/23/2020] [Indexed: 12/28/2022]
Abstract
BACKGROUND The clinical significance of rare mutations in LDL metabolism genes on nonalcoholic fatty liver disease (NAFLD) severity is not well understood. OBJECTIVE To examine the significance of mutations in LDL metabolism genes including apolipoprotein B (APOB), proprotein convertase subtilisin kexin 9 (PCSK9) and LDL receptor (LDLR) in patients with NAFLD. METHODS Patients with biopsy-confirmed NAFLD from the NASH Clinical Research Network studies were stratified into 3 groups of LDL-C (≤50 mg/dL, 130-150 mg/dL, ≥ 190 mg/dL) and then 120 (40 per group) were randomly selected from the strata. We examined the presence of mutations on LDL genes and analyzed its association with selected NAFLD-related features. Multivariable analyses were adjusted for age, race, gender and use of statins. RESULTS Among 40 patients with LDL-C ≤ 50 mg/dL, 7 (18%) patients had heterozygous variants in APOB and 2 had heterozygous variants in PCSK9 (5%). We also found heterozygous mutations in 3 (8%) patients with LDL-C ≥ 190 mg/dL; 2 and 1 located in LDLR and APOE genes, respectively. Compared to wild-type controls with LDL-C ≤ 50, APOB carriers displayed higher levels of alanine aminotransferase (85.86 ± 35.14 U/L vs 45.61 ± 20.84 U/L, Adj. P = 0.002) and steatosis >66% (57% vs 24%, Adj. P = 0.050). These associations remained statistically significant after excluding statin users. Other histological features of NAFLD severity were not different between wild-type controls and APOB mutation carriers. CONCLUSION Mutations in the APOB gene are common among NAFLD patients with very low LDL-C and may be associated with increased aminotransferase levels and steatosis severity.
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Affiliation(s)
- Eduardo Vilar-Gomez
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Samer Gawrieh
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tiebing Liang
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Adam D McIntyre
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Robert A Hegele
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Naga Chalasani
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
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13
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The interaction between brain and liver regulates lipid metabolism in the TBI pathology. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166078. [PMID: 33444711 DOI: 10.1016/j.bbadis.2021.166078] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/28/2020] [Accepted: 01/03/2021] [Indexed: 12/31/2022]
Abstract
To shed light on the impact of systemic physiology on the pathology of traumatic brain injury (TBI), we examine the effects of TBI (concussive injury) and dietary fructose on critical aspects of lipid homeostasis in the brain and liver of young-adult rats. Lipids are integral components of brain structure and function, and the liver has a role on the synthesis and metabolism of lipids. Fructose is mainly metabolized in the liver with potential implications for brain function. Lipidomic analysis accompanied by unbiased sparse partial least squares discriminant analysis (sPLS-DA) identified lysophosphatidylcholine (LPC) and cholesterol ester (CE) as the top lipid families impacted by TBI and fructose in the hippocampus, and only LPC (16:0) was associated with hippocampal-dependent memory performance. Fructose and TBI elevated liver pro-inflammatory markers, interleukin-1α (IL-1α), Interferon-γ (IFN-γ) that correlated with hippocampal-dependent memory dysfunction, and monocyte chemoattractant protein-1 (MCP-1) positively correlated with LPC levels in the hippocampus. The effects of fructose were more pronounced in the liver, in agreement with the role of liver on fructose metabolism and suggest that fructose could exacerbate liver inflammation caused by TBI. The overall results indicate that TBI and fructose interact to influence systemic and central inflammation by engaging liver lipids. The impact of TBI and fructose diet on the periphery provides a therapeutic target to counteract the TBI pathogenesis.
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14
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Berardo C, Di Pasqua LG, Cagna M, Richelmi P, Vairetti M, Ferrigno A. Nonalcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis: Current Issues and Future Perspectives in Preclinical and Clinical Research. Int J Mol Sci 2020; 21:ijms21249646. [PMID: 33348908 PMCID: PMC7766139 DOI: 10.3390/ijms21249646] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a continuum of liver abnormalities often starting as simple steatosis and to potentially progress into nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis and hepatocellular carcinoma. Because of its increasing prevalence, NAFLD is becoming a major public health concern, in parallel with a worldwide increase in the recurrence rate of diabetes and metabolic syndrome. It has been estimated that NASH cirrhosis may surpass viral hepatitis C and become the leading indication for liver transplantation in the next decades. The broadening of the knowledge about NASH pathogenesis and progression is of pivotal importance for the discovery of new targeted and more effective therapies; aim of this review is to offer a comprehensive and updated overview on NAFLD and NASH pathogenesis, the most recommended treatments, drugs under development and new drug targets. The most relevant in vitro and in vivo models of NAFLD and NASH will be also reviewed, as well as the main molecular pathways involved in NAFLD and NASH development.
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Affiliation(s)
| | | | | | | | | | - Andrea Ferrigno
- Correspondence: (L.G.D.P.); (A.F.); Tel.: +39-0382-986-451 (L.G.D.P.)
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15
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Tavaglione F, Targher G, Valenti L, Romeo S. Human and molecular genetics shed lights on fatty liver disease and diabetes conundrum. Endocrinol Diabetes Metab 2020; 3:e00179. [PMID: 33102799 PMCID: PMC7576307 DOI: 10.1002/edm2.179] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/28/2020] [Accepted: 08/01/2020] [Indexed: 12/13/2022] Open
Abstract
The causal role of abdominal overweight/obesity, insulin resistance and type 2 diabetes (T2D) on the risk of fatty liver disease (FLD) has robustly been proven. A consensus of experts has recently proposed the novel definition of 'metabolic dysfunction-associated fatty liver disease, MAFLD' instead of 'nonalcoholic fatty liver disease, NAFLD', emphasizing the central role of dysmetabolism in the disease pathogenesis. Conversely, a direct and independent contribution of FLD per se on risk of developing T2D is still a controversial topic. When dealing with FLD as a potential risk factor for T2D, it is straightforward to think of hepatic insulin resistance as the most relevant underlying mechanism. Emerging evidence supports genetic determinants of FLD (eg PNPLA3, TM6SF2, MBOAT7, GCKR, HSD17B13) as determinants of insulin resistance and T2D. However, recent studies highlighted that the key molecular mechanism of dysmetabolism is not fat accumulation per se but the degree of hepatic fibrosis (excess liver fat content-lipotoxicity), leading to reduced insulin clearance, insulin resistance and T2D. A consequence of these findings is that drugs that will ameliorate liver fat accumulation and fibrosis in principle may also exert a beneficial effect on insulin resistance and risk of T2D in individuals with FLD. Finally, initial findings show that these genetic factors might be directly implicated in modulating pancreatic beta-cell function, although future studies are needed to fully understand this relationship.
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Affiliation(s)
- Federica Tavaglione
- Clinical Medicine and Hepatology UnitDepartment of Internal Medicine and GeriatricsCampus Bio‐Medico UniversityRomeItaly
- Department of Molecular and Clinical MedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Giovanni Targher
- Section of Endocrinology, Diabetes and MetabolismDepartment of MedicineUniversity and Azienda Ospedaliera Universitaria Integrata of VeronaVeronaItaly
| | - Luca Valenti
- Department of Pathophysiology and TransplantationUniversità degli Studi di MilanoMilanoItaly
- Translational MedicineDepartment of Transfusion Medicine and HematologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoMilanoItaly
| | - Stefano Romeo
- Department of Molecular and Clinical MedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Clinical Nutrition UnitDepartment of Medical and Surgical ScienceMagna Graecia UniversityCatanzaroItaly
- Department of CardiologySahlgrenska University HospitalGothenburgSweden
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16
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Ruhanen H, Haridas PAN, Jauhiainen M, Olkkonen VM. Angiopoietin-like protein 3, an emerging cardiometabolic therapy target with systemic and cell-autonomous functions. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158791. [PMID: 32777482 DOI: 10.1016/j.bbalip.2020.158791] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/23/2020] [Accepted: 08/03/2020] [Indexed: 12/13/2022]
Abstract
Angiopoietin like protein 3 (ANGPTL3) is best known for its function as an inhibitor of lipoprotein and endothelial lipases. Due to the capacity of genetic or pharmacologic ANGPTL3 suppression to markedly reduce circulating lipoproteins, and the documented cardioprotection upon such suppression, ANGPTL3 has become an emerging therapy target for which both antibody and antisense oligonucleotide (ASO) therapeutics are being clinically tested. While the antibody is relatively selective for circulating ANGPTL3, the ASO also depletes the intra-hepatocellular protein, and there is emerging evidence for cell-autonomous functions of ANGPTL3 in the liver. These include regulation of hepatocyte glucose and fatty acid uptake, insulin sensitivity, LDL/VLDL remnant uptake, VLDL assembly/secretion, polyunsaturated fatty acid (PUFA) and PUFA-derived lipid mediator content, and gene expression. In this review we elaborate on (i) why ANGPTL3 is considered one of the most promising new cardiometabolic therapy targets, and (ii) the present evidences for its intra-hepatocellular or cell-autonomous functions.
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Affiliation(s)
- Hanna Ruhanen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Molecular and Integrative Biosciences, University of Helsinki, Finland
| | | | - Matti Jauhiainen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland.
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17
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Peterson LR, Jiang X, Chen L, Goldberg AC, Farmer MS, Ory DS, Schaffer JE. Alterations in plasma triglycerides and ceramides: links with cardiac function in humans with type 2 diabetes. J Lipid Res 2020; 61:1065-1074. [PMID: 32393551 PMCID: PMC7328042 DOI: 10.1194/jlr.ra120000669] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/15/2020] [Indexed: 12/23/2022] Open
Abstract
Cardiac dysfunction in T2D is associated with excessive FA uptake, oxidation, and generation of toxic lipid species by the heart. It is not known whether decreasing lipid delivery to the heart can effect improvement in cardiac function in humans with T2D. Thus, our objective was to test the hypothesis that lowering lipid delivery to the heart would result in evidence of decreased "lipotoxicity," improved cardiac function, and salutary effects on plasma biomarkers of cardiovascular risk. Thus, we performed a double-blind randomized placebo-controlled parallel design study of the effects of 12 weeks of fenofibrate-induced lipid lowering on cardiac function, inflammation, and oxidation biomarkers, and on the ratio of two plasma ceramides, Cer d18:1 (4E) (1OH, 3OH)/24:0 and Cer d18:1 (4E) (1OH, 3OH)/16:0 (i.e., "C24:0/C16:0"), which is associated with decreased risk of cardiac dysfunction and heart failure. Fenofibrate lowered plasma TG and cholesterol but did not improve heart systolic or diastolic function. Fenofibrate treatment lowered the plasma C24:0/C16:0 ceramide ratio and minimally altered oxidative stress markers but did not alter measures of inflammation. Overall, plasma TG lowering correlated with improvement of cardiac relaxation (diastolic function) as measured by tissue Doppler-derived parameter e'. Moreover, lowering the plasma C24:0/C16:0 ceramide ratio was correlated with worse diastolic function. These findings indicate that fenofibrate treatment per se is not sufficient to effect changes in cardiac function; however, decreases in plasma TG may be linked to improved diastolic function. In contrast, decreases in plasma C24:0/C16:0 are linked with worsening cardiac function.
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Affiliation(s)
- Linda R Peterson
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110. mailto:
| | - Xuntian Jiang
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Ling Chen
- Division of Biostatistics, Washington University School of Medicine, St. Louis, MO 63110
| | - Anne C Goldberg
- Division of Endocrinology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Marsha S Farmer
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Daniel S Ory
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Jean E Schaffer
- Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215
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18
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Bromelain Confers Protection against the Non-Alcoholic Fatty Liver Disease in Male C57bl/6 Mice. Nutrients 2020; 12:nu12051458. [PMID: 32443556 PMCID: PMC7285019 DOI: 10.3390/nu12051458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/18/2022] Open
Abstract
We aimed to investigate the effect of bromelain, the extract from stems of pineapples on the high-fat diet (HFD)-induced deregulation of hepatic lipid metabolism and non-alcoholic fatty liver disease (NAFLD), and its underlying mechanism in mice. Mice were daily administrated with HFD with or without bromelain (20 mg/kg) for 12 weeks, and we found that bromelain decreased the HFD-induced increase in body weight by ~30%, organ weight by ~20% in liver weight and ~40% in white adipose tissue weight. Additionally, bromelain attenuated HFD-induced hyperlipidemia by decreasing the serum level of total cholesterol by ~15% and triglycerides level by ~25% in mice. Moreover, hepatic lipid accumulation, particularly that of total cholesterol, free cholesterol, triglycerides, fatty acids, and glycerol, was decreased by 15–30% with bromelain treatment. Mechanistically, these beneficial effects of bromelain on HFD-induced hyperlipidemia and hepatic lipid accumulation may be attributed to the decreased fatty acid uptake and cholesteryl ester synthesis and the increased lipoprotein internalization, bile acid metabolism, cholesterol clearance, the assembly and secretion of very low-density lipoprotein, and the β-oxidation of fatty acids by regulating the protein expression involved in the above mentioned hepatic metabolic pathways. Collectively, these findings suggest that bromelain has therapeutic value for treating NAFLD and metabolic diseases.
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Abstract
PURPOSE OF REVIEW Several mutations in the apolipoprotein (apo) B, proprotein convertase subtilisin kexin 9 (PCSK9) and microsomal triglyceride transfer protein genes result in low or absent levels of apoB and LDL cholesterol (LDL-C) in plasma which cause familial hypobetalipoproteinemia (FHBL) and abetalipoproteinemia (ABL). Mutations in the angiopoietin-like protein 3 ANGPTL3 gene cause familial combined hypolipidemia (FHBL2). Clinical manifestations range from none-to-severe, debilitating and life-threatening disorders. This review summarizes recent genetic, metabolic and clinical findings and management strategies. RECENT FINDINGS Fatty liver, cirrhosis and hepatocellular carcinoma have been reported in FHBL and ABL probably due to decreased triglyceride export from the liver. Loss of function mutations in PCSK-9 and ANGPTL3 cause FHBL but not hepatic steatosis. In 12 case-control studies with 57 973 individuals, an apoB truncation was associated with a 72% reduction in coronary heart disease (odds ratio, 0.28; 95% confidence interval, 0.12-0.64; P = 0.002). PCSK9 inhibitors lowered risk of cardiovascular events in large, randomized trials without apparent adverse sequelae. SUMMARY Mutations causing low LDL-C and apoB have provided insight into lipid metabolism, disease associations and the basis for drug development to lower LDL-C in disorders causing high levels of cholesterol. Early diagnosis and treatment is necessary to prevent adverse sequelae from FHBL and ABL.
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Affiliation(s)
- Francine K Welty
- Division of Cardiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
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20
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Musialik J, Boguszewska-Chachulska A, Pojda-Wilczek D, Gorzkowska A, Szymańczak R, Kania M, Kujawa-Szewieczek A, Wojcieszyn M, Hartleb M, Więcek A. A Rare Mutation in The APOB Gene Associated with Neurological Manifestations in Familial Hypobetalipoproteinemia. Int J Mol Sci 2020; 21:ijms21041439. [PMID: 32093271 PMCID: PMC7073066 DOI: 10.3390/ijms21041439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/10/2020] [Accepted: 02/15/2020] [Indexed: 12/29/2022] Open
Abstract
Clinical phenotypes of familial hypobetalipoproteinemia (FHBL) are related to a number of defective apolipoprotein B (APOB) alleles. Fatty liver disease is a typical manifestation, but serious neurological symptoms can appear. In this study, genetic analysis of the APOB gene and ophthalmological diagnostics were performed for family members with FHBL. Five relatives with FHBL, including a proband who developed neurological disorders, were examined. A sequencing analysis of the whole coding region of the APOB gene, including flanking intronic regions, was performed using the next-generation sequencing (NGS) method. Electrophysiological ophthalmological examinations were also done. In the proband and his affected relatives, NGS identified the presence of the pathogenic, rare heterozygous splicing variant c.3696+1G>T. Two known heterozygous missense variants-c.2188G>A, p.(Val730Ile) and c.8353A>C, p.(Asn2785His)-in the APOB gene were also detected. In all patients, many ophthalmologic abnormalities in electrophysiological tests were also found. The identified splicing variant c.3696+1G>T can be associated with observed autosomal, dominant FHBL with coexisting neurological symptoms, and both identified missense variants could be excluded as the main cause of observed clinical signs, according to mutation databases and the literature. Electroretinography examination is a sensitive method for the detection of early neuropathy and should therefore be recommended for the care of patients with FHBL.
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Affiliation(s)
- Joanna Musialik
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia in Katowice, 40-055 Katowice, Poland; (A.K.-S.); (A.W.)
- Correspondence:
| | | | - Dorota Pojda-Wilczek
- Department of Ophthalmology, Medical University of Silesia in Katowice, 40-055 Katowice, Poland;
| | - Agnieszka Gorzkowska
- Department of Neurology, Department of Neurorehabilitation, Medical University of Silesia in Katowice, 40-055 Katowice, Poland;
| | | | - Magdalena Kania
- Genomed SA, 02-971 Warsaw, Poland; (A.B.-C.); (R.S.); (M.K.)
| | - Agata Kujawa-Szewieczek
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia in Katowice, 40-055 Katowice, Poland; (A.K.-S.); (A.W.)
| | - Małgorzata Wojcieszyn
- Department of Gastroenterology, II John Paul Pediatric Center, 41-200 Sosnowiec, Poland;
| | - Marek Hartleb
- Department of Gastroenterology and Hepatology, Medical University of Silesia in Katowice, 40-055 Katowice, Poland;
| | - Andrzej Więcek
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia in Katowice, 40-055 Katowice, Poland; (A.K.-S.); (A.W.)
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21
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Chen HC, Chen YZ, Wang CH, Lin FJ. The nonalcoholic fatty liver disease-like phenotype and lowered serum VLDL are associated with decreased expression and DNA hypermethylation of hepatic ApoB in male offspring of ApoE deficient mothers fed a with Western diet. J Nutr Biochem 2019; 77:108319. [PMID: 31926452 DOI: 10.1016/j.jnutbio.2019.108319] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 11/13/2019] [Accepted: 12/05/2019] [Indexed: 02/06/2023]
Abstract
Increasing evidence indicates that the intra-uterine environment has consequences for later life. However, the mechanisms of this fetal programming remain unclear. We aimed to investigate the impact of diet-induced maternal hypercholesterolemia on the predisposition of offspring to nonalcoholic fatty liver diseases (NAFLD) and metabolic diseases and its underlying mechanisms. Female apolipoprotein (Apo) E-deficient mice were fed a control diet (CD) or high fat/high cholesterol Western-type diet (WD) before and throughout pregnancy and lactation, and their offspring were weaned onto a CD postnatally. Strikingly, male offspring of WD-fed dams developed glucose intolerance and decreased peripheral insulin sensitivity and exhibited hepatic steatosis. Hepatic steatosis could be attributed, at least in part, to increased hepatic lipogenesis in E18.5 embryos and decreased serum VLDL levels in adulthood. In addition, males born to WD-fed dams had lower serum ApoB levels and hepatic ApoB gene expression compared with males born to CD-fed dams. DNA methylation analysis revealed increased methylation of CpG dinucleotides on the promoter region of the ApoB genes in the livers of male offspring of WD-fed dams. Our findings suggest that maternal WD intake can exacerbate the development of NAFLD in male offspring potentially by affecting ApoB gene expression through epigenetic alterations.
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Affiliation(s)
- Hsiao-Chien Chen
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Yi-Zhen Chen
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Chih-Hong Wang
- Department of Biological Science and Technology, National Chiao Tung University, HsinChu, Taiwan
| | - Fu-Jung Lin
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan; Research Center for Development Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan.
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22
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Noto D, Giammanco A, Barbagallo CM, Cefalù AB, Averna MR. Anti-PCSK9 treatment: is ultra-low low-density lipoprotein cholesterol always good? Cardiovasc Res 2019; 114:1595-1604. [PMID: 29931148 DOI: 10.1093/cvr/cvy144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 06/08/2018] [Indexed: 12/29/2022] Open
Abstract
Anti-PCSK9 (proprotein convertase subtilisin kexin 9) monoclonal antibodies (Mab) are novel, potent lipid-lowering drugs. They demonstrated to improve the lipid profile in high cardiovascular risk patients. Anti-PCSK9 Mab inhibit the targeted low-density lipoprotein (LDL)-receptor degradation induced by PCSK9 protein and are able to reduce LDL cholesterol (LDL-C) levels on top of conventional lipid-lowering therapy. Though these drugs proved to be very safe in the short-term, little is known about the possible long-term effects, due to the short period of their marketing. The genetic low cholesterol syndromes (LCS) represent the natural models of the lipid-lowering anti-PCSK9 therapy, and a valuable opportunity to predict the long-term effects of these drugs. By looking at the clinical features of such models, we could be able to foresee possible drug-induced side effects. In the present review, the correspondences and discordances between the side effects of anti-PCSK9 therapy and the corresponding LCS models will be examined in the attempt to forecast possible long-term consequences of these novel lipid-lowering agents.
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Affiliation(s)
- Davide Noto
- Department of Bioscience Internal Medicine and Specialties, University of Palermo, Palermo, Italy
| | - Antonina Giammanco
- Department of Bioscience Internal Medicine and Specialties, University of Palermo, Palermo, Italy
| | - Carlo M Barbagallo
- Department of Bioscience Internal Medicine and Specialties, University of Palermo, Palermo, Italy
| | - Angelo B Cefalù
- Department of Bioscience Internal Medicine and Specialties, University of Palermo, Palermo, Italy
| | - Maurizio R Averna
- Department of Bioscience Internal Medicine and Specialties, University of Palermo, Palermo, Italy
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Abstract
Familial hypercholesterolemia (FH) is a common genetic condition characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C), premature atherosclerotic cardiovascular disease, and considerable unmet medical need with conventional LDL-C-lowering therapies. Between 2012 and 2015, the US Food and Drug Administration approved four novel LDL-C-lowering agents for use in patients with FH based on the pronounced LDL-C-lowering efficacy of these medicines. We review the four novel approved agents, as well as promising LDL-C-lowering agents in clinical development, with a focus on their mechanism of action, efficacy in FH cohorts, and safety.
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Affiliation(s)
- Ezim Ajufo
- Departments of Medicine and Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104; ,
| | - Daniel J Rader
- Departments of Medicine and Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104; ,
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24
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In vitro functional characterization of splicing variants of the APOB gene found in familial hypobetalipoproteinemia. J Clin Lipidol 2019; 13:960-969. [PMID: 31629702 DOI: 10.1016/j.jacl.2019.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/22/2019] [Accepted: 09/06/2019] [Indexed: 11/23/2022]
Abstract
BACKGROUND Familial hypobetalipoproteinemia type 1 (FHBL-1) is a codominant disorder characterized by greatly reduced plasma levels of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B. Rare exonic pathogenic variants of APOB gene (nonsense variants, minute deletions/insertions and nonsynonymous variants) have been frequently reported in subjects with FHBL-1. Also, rare intronic variants of APOB located at intron/exon junctions and assumed to affect splicing have been reported. However, the pathogenicity of most of these intronic variants remains to be established. OBJECTIVE The objective of this study was the in vitro functional characterization of six splicing variants of APOB gene identified in seven putative FHBL-1 heterozygotes. METHODS ApoB minigenes harboring each variant were expressed in COS-1 cells and their transcripts were sequenced. RESULTS Four novel variants (c.237+1G>A, c.818+5G>A, c.3000-1G>T, and c.3842+1G>A), predicted in silico to obliterate splice site activity, were found to generate abnormal transcripts. The abnormal transcripts were generated by the activation of cryptic splice sites or exon skipping. All these transcripts harbored a premature termination codon and were predicted to encode truncated apoBs devoid of function. The predicted translation products were: i) p.(Lys41Serfs*2) and p.(Val80Ilefs*10) for c.237+1G>A; ii) p.(Asn274*) for c.818+5G>A; iii) p.(Leu1001Alafs*10) for c.3000-1G>T, and iv) p.(Ser1281Argfs*2) for c.3842+1G>A. Two previously annotated rare variants (c.905-15C>G and c.1618-4G>A) with uncertain effect in silico were found to generate only wild-type transcripts. CONCLUSIONS These in vitro minigene expression studies support the assignment of pathogenicity to four novel splice site variants of APOB gene found in FHBL-1.
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Ahmad Z, Banerjee P, Hamon S, Chan KC, Bouzelmat A, Sasiela WJ, Pordy R, Mellis S, Dansky H, Gipe DA, Dunbar RL. Inhibition of Angiopoietin-Like Protein 3 With a Monoclonal Antibody Reduces Triglycerides in Hypertriglyceridemia. Circulation 2019; 140:470-486. [PMID: 31242752 PMCID: PMC6686956 DOI: 10.1161/circulationaha.118.039107] [Citation(s) in RCA: 160] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Hypertriglyceridemia is associated with increased cardiovascular risk and may be caused by impaired lipoprotein clearance. Angiopoietin-like protein 3 (ANGPTL3) inhibits lipoprotein lipase activity, increasing triglycerides and other lipids. Evinacumab, an ANGPTL3 inhibitor, reduced triglycerides in healthy human volunteers and in homozygous familial hypercholesterolemic individuals. Results from 2 Phase 1 studies in hypertriglyceridemic subjects are reported here. Methods: Subjects with triglycerides >150 but ≤450 mg/dL and low-density lipoprotein cholesterol ≥100 mg/dL (n=83 for single ascending dose study [SAD]; n=56 for multiple ascending dose study [MAD]) were randomized 3:1 to evinacumab:placebo. SAD subjects received evinacumab subcutaneously at 75/150/250 mg, or intravenously at 5/10/20 mg/kg, monitored up to day 126. MAD subjects received evinacumab subcutaneously at 150/300/450 mg once weekly, 300/450 mg every 2 weeks, or intravenously at 20 mg/kg once every 4 weeks up to day 56 with 6 months of follow-up. The primary outcomes were incidence and severity of treatment-emergent adverse events. Efficacy analyses included changes in triglycerides and other lipids over time. Results: In the SAD, 32 (51.6%) versus 9 (42.9%) subjects on evinacumab versus placebo reported treatment-emergent adverse events. In the MAD, 21 (67.7%) versus 9 (75.0%) subjects on subcutaneously evinacumab versus placebo and 6 (85.7%) versus 1 (50.0%) on intravenously evinacumab versus placebo reported treatment-emergent adverse events. No serious treatment-emergent adverse events or events leading to death or treatment discontinuation were reported. Elevations in alanine aminotransferase (7 [11.3%] SAD), aspartate aminotransferase (4 [6.5%] SAD), and creatinine phosphokinase (2 [3.2%) SAD, 1 [14.3%] MAD) were observed with evinacumab (none in the placebo groups), which were single elevations and were not dose-related. Dose-dependent reductions in triglycerides were observed in both studies, with maximum reduction of 76.9% at day 3 with 10 mg/kg intravenously (P<0.0001) in the SAD and of 83.1% at day 2 with 20 mg/kg intravenously once every 4 weeks (P=0.0003) in the MAD. Significant reductions in other lipids were observed with most evinacumab doses versus placebo. Conclusion: Evinacumab was well-tolerated in 2 Phase 1 studies. Lipid changes in hypertriglyceridemic subjects were similar to those observed with ANGPTL3 loss-of-function mutations. Because the latter is associated with reduced cardiovascular risk, ANGPTL3 inhibition may improve clinical outcomes. Clinical Trial Registration: https://www.clinicaltrials.gov. Unique identifiers: NCT01749878 and NCT02107872.
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Affiliation(s)
- Zahid Ahmad
- Division of Nutrition and Metabolic Diseases, Department of Internal Medicine, Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas (Z.A.)
| | - Poulabi Banerjee
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Sara Hamon
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Kuo-Chen Chan
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Aurelie Bouzelmat
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - William J Sasiela
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Robert Pordy
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Scott Mellis
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Hayes Dansky
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Daniel A Gipe
- Regeneron Pharmaceuticals Inc, Tarrytown, NY (P.B., S.H., K.-C.C., A.B., W.JS., R.P., S.M., H.D., D.A.G.)
| | - Richard L Dunbar
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (R.L.D.)
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Hackl MT, Fürnsinn C, Schuh CM, Krssak M, Carli F, Guerra S, Freudenthaler A, Baumgartner-Parzer S, Helbich TH, Luger A, Zeyda M, Gastaldelli A, Buettner C, Scherer T. Brain leptin reduces liver lipids by increasing hepatic triglyceride secretion and lowering lipogenesis. Nat Commun 2019; 10:2717. [PMID: 31222048 PMCID: PMC6586634 DOI: 10.1038/s41467-019-10684-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/24/2019] [Indexed: 12/31/2022] Open
Abstract
Hepatic steatosis develops when lipid influx and production exceed the liver’s ability to utilize/export triglycerides. Obesity promotes steatosis and is characterized by leptin resistance. A role of leptin in hepatic lipid handling is highlighted by the observation that recombinant leptin reverses steatosis of hypoleptinemic patients with lipodystrophy by an unknown mechanism. Since leptin mainly functions via CNS signaling, we here examine in rats whether leptin regulates hepatic lipid flux via the brain in a series of stereotaxic infusion experiments. We demonstrate that brain leptin protects from steatosis by promoting hepatic triglyceride export and decreasing de novo lipogenesis independently of caloric intake. Leptin’s anti-steatotic effects are generated in the dorsal vagal complex, require hepatic vagal innervation, and are preserved in high-fat-diet-fed rats when the blood brain barrier is bypassed. Thus, CNS leptin protects from ectopic lipid accumulation via a brain-vagus-liver axis and may be a therapeutic strategy to ameliorate obesity-related steatosis. Obesity is associated with leptin resistance and rising blood leptin levels while central leptin exposure may be limited. Here, the authors show that brain leptin infusion reduces hepatic lipid content in rats by increasing hepatic VLDL secretion and lowering liver de novo lipogenesis via a vagal mechanism.
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Affiliation(s)
- Martina Theresa Hackl
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Clemens Fürnsinn
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Christina Maria Schuh
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Martin Krssak
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria.,Department of Biomedical Imaging and Image-Guided Therapy, High-Field MR Center, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, MOLIMA, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Fabrizia Carli
- Institute of Clinical Physiology, National Research Council, Via G. Moruzzi 1, 56124, Pisa, Italy
| | - Sara Guerra
- Institute of Clinical Physiology, National Research Council, Via G. Moruzzi 1, 56124, Pisa, Italy.,Institute of Life Sciences, Sant'Anna School of Advanced Studies, Via Santa Cecilia 3, 56127, Pisa, Italy
| | - Angelika Freudenthaler
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Sabina Baumgartner-Parzer
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Thomas H Helbich
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Anton Luger
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Maximilian Zeyda
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Amalia Gastaldelli
- Institute of Clinical Physiology, National Research Council, Via G. Moruzzi 1, 56124, Pisa, Italy.,Institute of Life Sciences, Sant'Anna School of Advanced Studies, Via Santa Cecilia 3, 56127, Pisa, Italy
| | - Christoph Buettner
- Departments of Medicine and Neuroscience, and Diabetes, Obesity and Metabolism Institute (DOMI), Icahn School of Medicine at Mt Sinai, One Gustave L. Levy Pl, New York, NY, 10029, USA
| | - Thomas Scherer
- Department of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria.
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Mouzaki M, Shah A, Arce-Clachar AC, Hardy J, Bramlage K, Xanthakos SA. Extremely low levels of low-density lipoprotein potentially suggestive of familial hypobetalipoproteinemia: A separate phenotype of NAFLD? J Clin Lipidol 2019; 13:425-431. [DOI: 10.1016/j.jacl.2019.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/23/2019] [Accepted: 02/07/2019] [Indexed: 12/25/2022]
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28
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Hartz J, Hegele RA, Wilson DP. Low LDL cholesterol—Friend or foe? J Clin Lipidol 2019; 13:367-373. [DOI: 10.1016/j.jacl.2019.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 01/19/2023]
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BasuRay S, Smagris E, Cohen JC, Hobbs HH. The PNPLA3 variant associated with fatty liver disease (I148M) accumulates on lipid droplets by evading ubiquitylation. Hepatology 2017; 66:1111-1124. [PMID: 28520213 PMCID: PMC5605398 DOI: 10.1002/hep.29273] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/08/2017] [Accepted: 05/11/2017] [Indexed: 12/14/2022]
Abstract
UNLABELLED A sequence variation (I148M) in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is strongly associated with fatty liver disease, but the underlying mechanism remains obscure. In this study, we used knock-in (KI) mice (Pnpla3148M/M ) to examine the mechanism responsible for accumulation of triglyceride (TG) and PNPLA3 in hepatic lipid droplets (LDs). No differences were found between Pnpla3148M/M and Pnpla3+/+ mice in hepatic TG synthesis, utilization, or secretion. These results are consistent with TG accumulation in the Pnpla3148M/M mice being caused by impaired TG mobilization from LDs. Sucrose feeding, which is required to elicit fatty liver in KI mice, led to a much larger and more persistent increase in PNPLA3 protein in the KI mice than in wild-type (WT) mice. Inhibition of the proteasome (bortezomib), but not macroautophagy (3-methyladenine), markedly increased PNPLA3 levels in WT mice, coincident with the appearance of ubiquitylated forms of the protein. Bortezomib did not increase PNPLA3 levels in Pnpla3148M/M mice, and only trace amounts of ubiquitylated PNPLA3 were seen in these animals. CONCLUSION These results are consistent with the notion that the 148M variant disrupts ubiquitylation and proteasomal degradation of PNPLA3, resulting in accumulation of PNPLA3-148M and impaired mobilization of TG from LDs. (Hepatology 2017;66:1111-1124).
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Affiliation(s)
- Soumik BasuRay
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasTX,Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Eriks Smagris
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasTX,Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Jonathan C. Cohen
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Helen H. Hobbs
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasTX,Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX,Howard Hughes Medical InstituteUniversity of Texas Southwestern Medical CenterDallasTX
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Magnolo L, Noto D, Cefalù AB, Averna M, Calandra S, Yao Z, Tarugi P. Characterization of a mutant form of human apolipoprotein B (Thr26_Tyr27del) associated with familial hypobetalipoproteinemia. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:371-9. [DOI: 10.1016/j.bbalip.2016.01.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/14/2015] [Accepted: 01/24/2016] [Indexed: 10/22/2022]
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31
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Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
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32
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Yilmaz BS, Mungan NO, Di Leo E, Magnolo L, Artuso L, Bernardis I, Tumgor G, Kor D, Tarugi P. Homozygous familial hypobetalipoproteinemia: A Turkish case carrying a missense mutation in apolipoprotein B. Clin Chim Acta 2016; 452:185-90. [DOI: 10.1016/j.cca.2015.11.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 11/15/2022]
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Burnett JR, Hooper AJ. Vitamin E and oxidative stress in abetalipoproteinemia and familial hypobetalipoproteinemia. Free Radic Biol Med 2015; 88:59-62. [PMID: 26086616 DOI: 10.1016/j.freeradbiomed.2015.05.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/07/2015] [Accepted: 05/26/2015] [Indexed: 01/13/2023]
Abstract
Abetalipoproteinemia (ABL) and familial hypobetalipoproteinemia (FHBL) are genetic diseases characterized by low density lipoprotein deficiency. ABL presents early in life with the gastroenterological manifestations of fat malabsorption, steatorrhea, and failure to thrive, and later in life, with progressive ophthalmopathy and neuropathy as a result of deficiency of the fat-soluble vitamins A and E. Heterozygous FHBL subjects are usually asymptomatic, but may develop fatty liver disease. In homozygous (compound heterozygous) FHBL, the clinical and biochemical features are indistinguishable from those of ABL and treatment recommendations are the same: dietary fat restriction to prevent steatorrhea, and long-term high-dose vitamin E and A supplementation to prevent or at least slow the progression of neuromuscular and retinal degenerative disease. Despite their low plasma vitamin E levels, individuals with heterozygous FHBL do not require vitamin E supplementation. There are conflicting reports on whether increased oxidative stress is seen in ABL; these differences may relate to the small size of patient groups as well as differences in patient age and dose of vitamin E supplementation, or the contribution from dietary sources of vitamin E. High density lipoproteins in ABL appear to be severely oxidized yet able to inhibit platelet aggregation by binding to scavenger receptor B1. We review the role of vitamin E and oxidative stress in ABL and FHBL.
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Affiliation(s)
- John R Burnett
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Australia.
| | - Amanda J Hooper
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Australia; School of Pathology & Laboratory Medicine, University of Western Australia, Perth, Australia
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Fabbrini E, Magkos F. Hepatic Steatosis as a Marker of Metabolic Dysfunction. Nutrients 2015; 7:4995-5019. [PMID: 26102213 PMCID: PMC4488828 DOI: 10.3390/nu7064995] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 06/05/2015] [Accepted: 06/15/2015] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the liver manifestation of the complex metabolic derangements associated with obesity. NAFLD is characterized by excessive deposition of fat in the liver (steatosis) and develops when hepatic fatty acid availability from plasma and de novo synthesis exceeds hepatic fatty acid disposal by oxidation and triglyceride export. Hepatic steatosis is therefore the biochemical result of an imbalance between complex pathways of lipid metabolism, and is associated with an array of adverse changes in glucose, fatty acid, and lipoprotein metabolism across all tissues of the body. Intrahepatic triglyceride (IHTG) content is therefore a very good marker (and in some cases may be the cause) of the presence and the degree of multiple-organ metabolic dysfunction. These metabolic abnormalities are likely responsible for many cardiometabolic risk factors associated with NAFLD, such as insulin resistance, type 2 diabetes mellitus, and dyslipidemia. Understanding the factors involved in the pathogenesis and pathophysiology of NAFLD will lead to a better understanding of the mechanisms responsible for the metabolic complications of obesity, and hopefully to the discovery of novel effective treatments for their reversal.
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Affiliation(s)
- Elisa Fabbrini
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Faidon Magkos
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Hepatocyte-Specific Depletion of UBXD8 Induces Periportal Steatosis in Mice Fed a High-Fat Diet. PLoS One 2015; 10:e0127114. [PMID: 25970332 PMCID: PMC4430229 DOI: 10.1371/journal.pone.0127114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 04/10/2015] [Indexed: 12/19/2022] Open
Abstract
We showed previously that UBXD8 plays a key role in proteasomal degradation of lipidated ApoB in hepatocarcinoma cell lines. In the present study, we aimed to investigate the functions of UBXD8 in liver in vivo. For this purpose, hepatocyte-specific UBXD8 knockout (UBXD8-LKO) mice were generated. They were fed with a normal or high-fat diet, and the phenotypes were compared with those of littermate control mice. Hepatocytes obtained from UBXD8-LKO and control mice were analyzed in culture. After 26 wk of a high-fat diet, UBXD8-LKO mice exhibited macrovesicular steatosis in the periportal area and microvesicular steatosis in the perivenular area, whereas control mice exhibited steatosis only in the perivenular area. Furthermore, UBXD8-LKO mice on a high-fat diet had significantly lower concentrations of serum triglyceride and VLDL than control mice. A Triton WR-1339 injection study revealed that VLDL secretion from hepatocytes was reduced in UBXD8-LKO mice. The decrease of ApoB secretion upon UBXD8 depletion was recapitulated in cultured primary hepatocytes. Accumulation of lipidated ApoB in lipid droplets was observed only in UBXD8-null hepatocytes. The results showed that depletion of UBXD8 in hepatocytes suppresses VLDL secretion, and could lead to periportal steatosis when mice are fed a high-fat diet. This is the first demonstration that an abnormality in the intracellular ApoB degradation mechanism can cause steatosis, and provides a useful model for periportal steatosis, which occurs in several human diseases.
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Xu L, Gu S, Feng Q, Liang C, Xin SX. Quantitative study of liver magnetic resonance spectroscopy quality at 3T using body and phased array coils with physical analysis and clinical evaluation. PLoS One 2015; 10:e0122999. [PMID: 25881016 PMCID: PMC4400076 DOI: 10.1371/journal.pone.0122999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 02/26/2015] [Indexed: 01/20/2023] Open
Abstract
This study aims to investigate the quality difference of short echo time (TE) breathhold 1H magnetic resonance spectroscopy (MRS) of the liver at 3.0T using the body and phased array coils, respectively. In total, 20 pairs of single-voxel proton spectra of the liver were acquired at 3.0T using the phased array and body coils as receivers. Consecutive stacks of breathhold spectra were acquired using the point resolved spectroscopy (PRESS) technique at a short TE of 30 ms and a repetition time (TR) of 1500 ms. The first spectroscopy sequence was “copied” for the second acquisition to ensure identical voxel positioning. The MRS prescan adjustments of shimming and water suppression, signal-to noise ratio (SNR), and major liver quantitative information were compared between paired spectra. Theoretical calculation of the SNR and homogeneity of the region of interest (ROI, 2 cm×2 cm×2 cm) using different coils loaded with 3D liver electromagnetic model of real human body was implemented in the theoretical analysis. The theoretical analysis showed that, inside the ROI, the SNR of the phase array coil was 2.8387 times larger than that of body coil and the homogeneity of the phase array coil and body coil was 80.10% and 93.86%, respectively. The experimental results showed excellent correlations between the paired data (all r > 0.86). Compared with the body coil group, the phased array group had slightly worse shimming effect and better SNR (all P values < .01). The discrepancy of the line width because of the different coils was approximately 0.8 Hz (0.00625 ppm). No significant differences of the major liver quantitative information of Cho/Lip2 height, Cho/Lip2 area, and lipid content were observed (all P values >0.05). The theoretical analysis and clinical experiment showed that the phased array coil was superior to the body coil with respect to 3.0T breathhold hepatic proton MRS.
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Affiliation(s)
- Li Xu
- Department of Radiology, Guangdong Provincial Traditional Chinese Medicine Hospital & postdoctoral mobile research station of Guangzhou University of Traditional Chinese Medicine, Guangzhou, Guangdong Province, People’s Republic of China
| | - Shiyong Gu
- Biomedical Engineering School of the Southern Medical University, Guangzhou, Guangdong Province, People’s Republic of China
| | - Qianjin Feng
- Biomedical Engineering School of the Southern Medical University, Guangzhou, Guangdong Province, People’s Republic of China
- * E-mail: (QF); (SXX)
| | - Changhong Liang
- Department of Radiology, Guangdong General Hospital, Guangzhou, Guangdong Province, People’s Republic of China
| | - Sherman Xuegang Xin
- Biomedical Engineering School of the Southern Medical University, Guangzhou, Guangdong Province, People’s Republic of China
- Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, New York, United States of America
- * E-mail: (QF); (SXX)
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Wang X, Wang D, Shan Z. Clinical and genetic analysis of a family diagnosed with familial hypobetalipoproteinemia in which the proband was diagnosed with diabetes mellitus. Atherosclerosis 2015; 239:552-6. [PMID: 25733326 DOI: 10.1016/j.atherosclerosis.2015.02.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 02/09/2015] [Accepted: 02/16/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To perform clinical and genetic analysis of a family with familial hypobetalipoproteinemia in which the proband had been diagnosed with diabetes mellitus. METHODS Direct sequencing was performed on candidate genes such as APOB, PCSK9, and ANGPTL3. The effect of the mutant gene on lipid profile was investigated using biochemical methods. RESULTS A novel mutation Y344S in ANGPTL3 was identified but no variants were found in PCSK9 or APOB. Lipid profiles showed the levels of TG, TC, and LDL-C to be significantly lower in Y344S carriers than in non-carriers in this family. The levels of HDL-C and plasma concentrations of ANGPTL3 showed no significant differences. Western blot analysis revealed that the mutant ANGPTL3 proteins could not be secreted into the medium. CONCLUSION A novel mutation Y344S was found in ANGPTL3 gene in two diabetic patients with familial hypobetalipoproteinemia. The family study and genetic analysis suggest that this set of gene mutation may be a genetic basis for the lipid phenotypes, and may become a vascular protective factor in the probands with high risk of atherosclerosis.
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Affiliation(s)
- Xiaoli Wang
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Shenyang 110001, PR China.
| | - Dongdong Wang
- Department of Obstetrics and Gynecology of Shengjing Hospital, China Medical University, Shenyang 110001, PR China
| | - Zhongyan Shan
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Shenyang 110001, PR China
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The Janus-faced manifestations of homozygous familial hypobetalipoproteinemia due to apolipoprotein B truncations. J Clin Lipidol 2015; 9:400-5. [PMID: 26073401 DOI: 10.1016/j.jacl.2015.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 12/05/2014] [Accepted: 01/18/2015] [Indexed: 11/23/2022]
Abstract
Familial hypobetalipoproteinemia is a codominant disorder characterized by low plasma levels of low-density lipoprotein cholesterol and apolipoprotein B (apoB), which in ∼50% of the cases is due to mutations in APOB gene. In most cases, these mutations cause the formation of truncated apoBs of various sizes, which have a reduced capacity to bind lipids and form lipoprotein particles. Here, we describe 2 children with severe hypobetalipoproteinemia found to be homozygous for novel APOB gene mutations. The first case (HBL-201) was an asymptomatic 13-year-old boy incidentally found to have slightly elevated serum transaminases associated with hepatic steatosis. He was homozygous for a truncated apoB (2211 amino acids, apoB-48.74) whose size is similar to that of wild-type apoB-48 (2152 amino acids) produced by the intestine. ApoB-48.74 is expected to be incorporated into chylomicrons in the intestine but might have a reduced capacity to form secretion-competent very low-density lipoprotein in the liver. The second patient (HBL-96) was a 6-month-old girl suspected to have abetalipoproteinemia, for the presence of chronic diarrhea, failure to thrive, extremely severe hypobetalipoproteinemia, and low plasma levels of vitamin E and vitamin A. She was homozygous for a nonsense mutation (Gln513*) resulting in a short truncated apoB (apoB-11.30), which is not secreted into the plasma. In this patient, the impaired chylomicron formation is responsible for the severe clinical manifestations and growth retardation. In homozygous familial hypobetalipoproteinemia, the capacity of truncated apoBs to form chylomicrons is the major factor, which affects the severity of the clinical manifestations.
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Abstract
"Primary hypobetalipoproteinemia" refers to an eclectic group of inherited lipoprotein disorders characterized by low concentrations of or absence of low-density lipoprotein cholesterol and apolipoprotein B in plasma. Abetalipoproteinemia and homozygous familial hypobetalipoproteinemia, although caused by mutations in different genes, are clinically indistinguishable. A framework for the clinical follow-up and management of these two disorders has been proposed recently, focusing on monitoring of growth in children and preventing complications by providing specialized dietary advice and fat-soluble vitamin therapeutic regimens. Other recent publications on familial combined hypolipidemia suggest that although a reduction of angiopoietin-like 3 activity may improve insulin sensitivity, complete deficiency also reduces serum cholesterol efflux capacity and increases the risk of early vascular atherosclerotic changes, despite low low-density lipoprotein cholesterol levels. Specialist laboratories offer exon-by-exon sequence analysis for the molecular diagnosis of primary hypobetalipoproteinemia. In the future, massively parallel sequencing of panels of genes involved in dyslipidemia may play a greater role in the diagnosis of these conditions.
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Levy E. Insights from human congenital disorders of intestinal lipid metabolism. J Lipid Res 2014; 56:945-62. [PMID: 25387865 DOI: 10.1194/jlr.r052415] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Indexed: 12/24/2022] Open
Abstract
The intestine must challenge the profuse daily flux of dietary fat that serves as a vital source of energy and as an essential component of cell membranes. The fat absorption process takes place in a series of orderly and interrelated steps, including the uptake and translocation of lipolytic products from the brush border membrane to the endoplasmic reticulum, lipid esterification, Apo synthesis, and ultimately the packaging of lipid and Apo components into chylomicrons (CMs). Deciphering inherited disorders of intracellular CM elaboration afforded new insight into the key functions of crucial intracellular proteins, such as Apo B, microsomal TG transfer protein, and Sar1b GTPase, the defects of which lead to hypobetalipoproteinemia, abetalipoproteinemia, and CM retention disease, respectively. These "experiments of nature" are characterized by fat malabsorption, steatorrhea, failure to thrive, low plasma levels of TGs and cholesterol, and deficiency of liposoluble vitamins and essential FAs. After summarizing and discussing the functions and regulation of these proteins for reader's comprehension, the current review focuses on their specific roles in malabsorptions and dyslipidemia-related intestinal fat hyperabsorption while dissecting the spectrum of clinical manifestations and managements. The influence of newly discovered proteins (proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 protein) on fat absorption has also been provided. Finally, it is stressed how the overexpression or polymorphism status of the critical intracellular proteins promotes dyslipidemia and cardiometabolic disorders.
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Affiliation(s)
- Emile Levy
- Research Centre, CHU Sainte-Justine and Department of Nutrition, Université de Montréal, Montreal, Quebec H3T 1C5, Canada
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41
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Abstract
Accumulation of triacylglycerols within the cytoplasm of hepatocytes to the degree that lipid droplets are visible microscopically is called liver steatosis. Most commonly, it occurs when there is an imbalance between the delivery or synthesis of fatty acids in the liver and their disposal through oxidative pathways or secretion into the blood as a component of triacylglycerols in very low density lipoprotein. This disorder is called nonalcoholic fatty liver disease (NAFLD) in the absence of alcoholic abuse and viral hepatitis, and it is often associated with insulin resistance, obesity and type 2 diabetes. Also, liver steatosis can be induced by many other causes including excessive alcohol consumption, infection with genotype 3 hepatitis C virus and certain medications. Whereas hepatic triacylglycerol accumulation was once considered the ultimate effector of hepatic lipotoxicity, triacylglycerols per se are quite inert and do not induce insulin resistance or cellular injury. Rather, lipotoxic injury in the liver appears to be mediated by the global ongoing fatty acid enrichment in the liver, paralleling the development of insulin resistance. A considerable number of fatty acid metabolites may be responsible for hepatic lipotoxicity and liver injury. Additional key contributors include hepatic cytosolic lipases and the "lipophagy" of lipid droplets, as sources of hepatic fatty acids. The specific origin of the lipids, mainly triacylglycerols, accumulating in liver has been unraveled by recent kinetic studies, and identifying the origin of the accumulated triacylglycerols in the liver of patients with NAFLD may direct the prevention and treatment of this condition.
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Affiliation(s)
- David Q-H Wang
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St. Louis, Missouri
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42
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Burnett JR, Bell DA, Hooper AJ, Hegele RA. Clinical utility gene card for: Familial hypobetalipoproteinaemia (APOB)--Update 2014. Eur J Hum Genet 2014; 23:ejhg2014225. [PMID: 25335495 DOI: 10.1038/ejhg.2014.225] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/08/2014] [Accepted: 09/19/2014] [Indexed: 01/08/2023] Open
Affiliation(s)
- John R Burnett
- 1] Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia [2] School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia
| | - Damon A Bell
- 1] Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia [2] School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia
| | - Amanda J Hooper
- 1] Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia [2] School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia [3] School of Pathology & Laboratory Medicine, University of Western Australia, Perth, Western Australia, Australia
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Di Filippo M, Moulin P, Roy P, Samson-Bouma ME, Collardeau-Frachon S, Chebel-Dumont S, Peretti N, Dumortier J, Zoulim F, Fontanges T, Parini R, Rigoldi M, Furlan F, Mancini G, Bonnefont-Rousselot D, Bruckert E, Schmitz J, Scoazec JY, Charrière S, Villar-Fimbel S, Gottrand F, Dubern B, Doummar D, Joly F, Liard-Meillon ME, Lachaux A, Sassolas A. Homozygous MTTP and APOB mutations may lead to hepatic steatosis and fibrosis despite metabolic differences in congenital hypocholesterolemia. J Hepatol 2014; 61:891-902. [PMID: 24842304 DOI: 10.1016/j.jhep.2014.05.023] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 04/16/2014] [Accepted: 05/06/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic steatohepatitis leading to fibrosis occurs in patients with abetalipoproteinemia (ABL) and homozygous or compound heterozygous familial hypobetalipoproteinemia (Ho-FHBL). We wanted to establish if liver alterations were more frequent in one of both diseases and were influenced by comorbidities. METHODS We report genetic, clinical, histological and biological characteristics of new cases of ABL (n =7) and Ho-FHBL (n = 7), and compare them with all published ABL (51) and Ho-FHBL (22) probands. RESULTS ABL patients, diagnosed during infancy, presented mainly with diarrhea, neurological and ophthalmological impairments and remained lean, whereas Ho-FHBL were diagnosed later, with milder symptoms often becoming overweight in adulthood. Despite subtle differences in lipid phenotype, liver steatosis was observed in both groups with a high prevalence of severe fibrosis (5/27 for Ho-FHBL vs. 4/58 for ABL (n.s.)). Serum triglycerides concentration was higher in Ho-FHBL whereas total and HDL-cholesterol were similar in both groups. In Ho-FHBL liver alterations were found to be independent from the apoB truncation size and apoB concentrations. CONCLUSIONS Our findings provide evidence for major liver abnormalities in both diseases. While ABL and Ho-FHBL patients have subtle differences in lipid phenotype, carriers of APOB mutations are more frequently obese. These results raise the question of a complex causal link between apoB metabolism and obesity. They suggest that the genetic defect in VLDL assembly is critical for the occurrence of liver steatosis leading to fibrosis and shows that obesity and insulin resistance might contribute by increasing lipogenesis.
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Affiliation(s)
- Mathilde Di Filippo
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et de Biologie Moléculaire du GHE, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Lyon, France; INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France.
| | - Philippe Moulin
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France; Fédération d'Endocrinologie, Maladies métaboliques, Diabète et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Pascal Roy
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France; Centre National de la Recherche Scientifique UMR5558, Univ Lyon-1, Villeurbanne, France
| | | | | | - Sabrina Chebel-Dumont
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et de Biologie Moléculaire du GHE, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Lyon, France
| | - Noël Peretti
- Service de Gastroentérologie Hépatologie et Nutrition Pédiatrique, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
| | - Jérôme Dumortier
- Fédération des Spécialités Digestives, Hôpital Edouard Herriot, Hospices Civils, Lyon, France
| | - Fabien Zoulim
- Service d'Hépato-Gastro-Entérologie, Hôpital de la Croix Rousse, Hospices Civils, Lyon, France
| | - Thierry Fontanges
- Service d'Hépato-Gastro-Entérologie, Centre Hospitalier Pierre Oudot, Bourgoin Jallieu, France
| | - Rossella Parini
- Rare Metabolic Disease Unit, Department of Pediatrics, Fondazione MBBM, San Gerardo Hospital, Monza, Italy
| | - Miriam Rigoldi
- Rare Metabolic Disease Unit, Department of Pediatrics, Fondazione MBBM, San Gerardo Hospital, Monza, Italy
| | - Francesca Furlan
- Rare Metabolic Disease Unit, Department of Pediatrics, Fondazione MBBM, San Gerardo Hospital, Monza, Italy
| | - Grazia Mancini
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Dominique Bonnefont-Rousselot
- Unité pédagogique de Biochimie, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France; UPMC University Paris 6, UMR_S1166 Inserm ICAN, Paris, France; Service de Biochimie métabolique, Groupe hospitalier Pitié-Salpêtrière-Charles Foix, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Eric Bruckert
- Service d'Endocrinologie, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France
| | - Jacques Schmitz
- Service de Gastroentérologie Pédiatrique, Hôpital Necker-Enfants Malades, AP-HP, Paris, France
| | - Jean Yves Scoazec
- Service d'anatomie pathologique, Hôpital Edouard Herriot, Hospices Civils, Lyon, France
| | - Sybil Charrière
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France; Fédération d'Endocrinologie, Maladies métaboliques, Diabète et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Sylvie Villar-Fimbel
- Fédération d'Endocrinologie, Maladies métaboliques, Diabète et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Frederic Gottrand
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Jeanne de Flandre university hospital, Lille, France
| | - Béatrice Dubern
- Nutrition et Gastroentérologie Pédiatriques, Hôpital Trousseau, AP-HP, Paris, France; Institut de Cardiométabolisme et Nutrition (ICAN), INSERM UMRS U872 (Eq7) Nutriomique, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Diane Doummar
- Service de Neuropédiatrie, Hôpital Trousseau, Paris, France
| | - Francesca Joly
- Service de Gastroentérologie et d'Assistance Nutritive, Hôpital Beaujon, Clichy, France
| | | | - Alain Lachaux
- Service de Gastroentérologie Hépatologie et Nutrition Pédiatrique, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France; INSERM U 1111, Faculté de médecine Lyon Est, Université Lyon 1, Lyon, France
| | - Agnès Sassolas
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et de Biologie Moléculaire du GHE, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Lyon, France; INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
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Abstract
PURPOSE OF REVIEW Several mutations in the apoB, proprotein convertase subtilisin/kexin type 9 (PCSK9), and MTP genes result in low or absent levels of apoB and LDL-cholesterol in plasma, which cause familial hypobetalipoproteinemia and abetalipoproteinemia. Mutations in the ANGPTL3 gene cause familial combined hypolipidemia. Clinical manifestations range from none to severe, debilitating, and life-threatening disorders. This review summarizes recent genetic, metabolic, and clinical findings and presents an update on management strategies. RECENT FINDINGS Cases of cirrhosis and hepatocellular carcinoma have now been identified in heterozygous familial hypobetalipoproteinemia probably because of decreased triglyceride transport capacity from the liver. ANGPTL3 mutations cause low levels of LDL-cholesterol and low HDL-cholesterol in compound heterozygotes and homozygous individuals, decrease reverse cholesterol transport, and lower glucose levels. The effect on atherosclerosis is unknown; however, severe fatty liver has been identified. Loss-of-function mutations in PCSK9 cause familial hypobetalipoproteinemia, which appears to lower risk for coronary artery disease and has no adverse sequelae. Phase III clinical trials are now underway examining the effect of PCSK9 inhibitors on cardiovascular events in combination with statin drugs. SUMMARY Mutations causing low LDL-cholesterol and apoB have provided insight into lipid metabolism, disease associations, and the basis for drug development to lower LDL-cholesterol in disorders causing high levels of cholesterol. Early diagnosis and treatment are necessary to prevent adverse sequelae from familial hypobetalipoproteinemia and abetalipoproteinemia.
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Affiliation(s)
- Francine K Welty
- Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
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45
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Quick nuclear transportation of siRNA and in vivo hepatic ApoB gene silencing with galactose-bearing polymeric carrier. J Biotechnol 2014; 175:15-21. [DOI: 10.1016/j.jbiotec.2014.01.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/18/2014] [Accepted: 01/27/2014] [Indexed: 12/20/2022]
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Minicocci I, Santini S, Cantisani V, Stitziel N, Kathiresan S, Arroyo JA, Martí G, Pisciotta L, Noto D, Cefalù AB, Maranghi M, Labbadia G, Pigna G, Pannozzo F, Ceci F, Ciociola E, Bertolini S, Calandra S, Tarugi P, Averna M, Arca M. Clinical characteristics and plasma lipids in subjects with familial combined hypolipidemia: a pooled analysis. J Lipid Res 2013; 54:3481-90. [PMID: 24058201 DOI: 10.1194/jlr.p039875] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Angiopoietin-like 3 (ANGPTL3) regulates lipoprotein metabolism by modulating extracellular lipases. Loss-of function mutations in ANGPTL3 gene cause familial combined hypolipidemia (FHBL2). The mode of inheritance and hepatic and vascular consequences of FHBL2 have not been fully elucidated. To get further insights on these aspects, we reevaluated the clinical and the biochemical characteristics of all reported cases of FHBL2. One hundred fifteen FHBL2 individuals carrying 13 different mutations in the ANGPTL3 gene (14 homozygotes, 8 compound heterozygotes, and 93 heterozygotes) and 402 controls were considered. Carriers of two mutant alleles had undetectable plasma levels of ANGPTL3 protein, whereas heterozygotes showed a reduction ranging from 34% to 88%, according to genotype. Compared with controls, homozygotes as well as heterozygotes showed a significant reduction of all plasma lipoproteins, while no difference in lipoprotein(a) [Lp(a)] levels was detected between groups. The prevalence of fatty liver was not different in FHBL2 subjects compared with controls. Notably, diabetes mellitus and cardiovascular disease were absent among homozygotes. FHBL2 trait is inherited in a codominant manner, and the lipid-lowering effect of two ANGPTL3 mutant alleles was more than four times larger than that of one mutant allele. No changes in Lp(a) were detected in FHBL2. Furthermore, our analysis confirmed that FHBL2 is not associated with adverse clinical sequelae. The possibility that FHBL2 confers lower risk of diabetes and cardiovascular disease warrants more detailed investigation.
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Affiliation(s)
- Ilenia Minicocci
- Departments of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
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Martín-Morales R, García-Díaz JD, Tarugi P, González-Santos P, Saavedra-Vallejo P, Magnolo L, Mesa-Latorre JM, di Leo E, Valdivielso P. Familial hypobetalipoproteinemia: analysis of three Spanish cases with two new mutations in the APOB gene. Gene 2013; 531:92-6. [PMID: 24001780 DOI: 10.1016/j.gene.2013.08.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 01/25/2023]
Abstract
Extremely low LDL-cholesterol concentrations are very unusual and generally related with comorbidities accompanying malnutrition. Less frequently low LDL-cholesterol levels result from mutations in the APOB, PCSK9, ANGPTL3, SAR1B and MTTP genes (primary hypobetalipoproteinemia). We investigated three patients with plasma LDL-cholesterol levels below the fifth percentile of the Spanish population. We recorded data on demographic and anthropometric characteristics, life style habits, physical examination, liver ultrasound and lipid and lipoprotein levels, in the probands and their first-degree relatives. Secondary causes of hypocholesterolemia were ruled out by clinical study, complementary tests and follow-up. The APOB, MTTP and SAR1B genes were sequenced. Patients were found to be heterozygotes for point mutations located in the exon 26 of the APOB gene. One patient, with fatty liver, carried a previously described mutation (c.7600C>T) (Arg2507X), causing the formation of truncated Apo B-55.25. The other two mutations producing truncations are new. One asymptomatic patient carried the Arg3672X (Apo B-80.93) and the other with fatty liver and steatorrhea carried the Ser2184fsVal2193X (Apo B-48.32). Our study reinforces the concept that in the heterozygous carriers of truncated Apo Bs, the clinical manifestations of FHBL are dependent on the size of the truncations.
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Affiliation(s)
- R Martín-Morales
- Unidad de Lípidos, Unidad de Gestión Clínica de Medicina Interna, Instituto de Biomedicina de Málaga (IBIMA), Hospital Universitario Virgen de la Victoria, Universidad de Malaga, Spain
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48
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Non-alcoholic steatohepatitis-related cirrhosis in a patient with APOB L343V familial hypobetalipoproteinaemia. Clin Chim Acta 2013; 421:121-5. [DOI: 10.1016/j.cca.2013.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/01/2013] [Accepted: 03/01/2013] [Indexed: 01/01/2023]
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Cefalù AB, Pirruccello JP, Noto D, Gabriel S, Valenti V, Gupta N, Spina R, Tarugi P, Kathiresan S, Averna MR. A novel APOB mutation identified by exome sequencing cosegregates with steatosis, liver cancer, and hypocholesterolemia. Arterioscler Thromb Vasc Biol 2013; 33:2021-5. [PMID: 23723369 DOI: 10.1161/atvbaha.112.301101] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE In familial hypobetalipoproteinemia, fatty liver is a characteristic feature, and there are several reports of associated cirrhosis and hepatocarcinoma. We investigated a large kindred in which low-density lipoprotein cholesterol, fatty liver, and hepatocarcinoma displayed an autosomal dominant pattern of inheritance. APPROACH AND RESULTS The proband was a 25-year-old female with low plasma cholesterol and hepatic steatosis. Low plasma levels of total cholesterol and fatty liver were observed in 10 more family members; 1 member was affected by liver cirrhosis, and 4 more subjects died of either hepatocarcinoma or carcinoma on cirrhosis. To identify the causal mutation in this family, we performed exome sequencing in 2 participants with hypocholesterolemia and fatty liver. Approximately 22 400 single nucleotide variants were identified in each sample. After variant filtering, 300 novel shared variants remained. A nonsense variant, p.K2240X, attributable to an A>T mutation in exon 26 of APOB (c.6718A>T) was identified, and this variant was confirmed by Sanger sequencing. The gentotypic analysis of 16 family members in total showed that this mutation segregated with the low cholesterol trait. In addition, genotyping of the PNPLA3 p.I148M did not show significant frequency differences between carriers and noncarriers of the c.6718A>T APOB gene mutation. CONCLUSIONS We used exome sequencing to discover a novel nonsense mutation in exon 26 of APOB (p.K2240X) responsible for low cholesterol and fatty liver in a large kindred. This mutation may also be responsible for cirrhosis and liver cancer in this family.
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Affiliation(s)
- Angelo B Cefalù
- Dipartimento Biomedico di Medicina Interna e Specialistica, Università degli Studi di Palermo, Palermo, Italy
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Hovingh K, Besseling J, Kastelein J. Efficacy and safety of mipomersen sodium (Kynamro). Expert Opin Drug Saf 2013; 12:569-79. [PMID: 23611600 DOI: 10.1517/14740338.2013.793670] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Mipomersen is a first-in-class drug indicated as an adjunct to lipid-lowering medications and diet to reduce low-density lipoprotein-cholesterol (LDL-C), apolipoprotein B (apoB), total cholesterol (TC) and non-high density lipoprotein-cholesterol (non-HDL-C) in patients with homozygous familial hypercholesterolemia (HoFH). AREAS COVERED This article summarizes the efficacy and safety profile of mipomersen based on literature, public materials available from the Endocrinologic and Metabolic Drugs Advisory Committee meeting (FDA) in review of the New Drug Application (NDA 203568) and the recent product label. EXPERT OPINION Patients suffering from HoFH are characterized by elevated levels of LDL-C and are, therefore, at severely increased risk for cardiovascular disease (CVD). Currently available lipid-lowering therapies (LLT), such as statins, have been shown to lower LDL-C levels and CVD risk. However, in patients suffering from HoFH, additional therapy is urgently needed to further decrease LDL-C levels and CVD risk. Mipomersen (Kynamro) has recently been approved by the FDA as a novel LLT modality in patients with HoFH. Mipomersen has been show to result in highly relevant absolute LDL-C reductions in HoFH patients, and given the undisputed causal relationship between LDL-C levels and CVD risk, this additional LDL-C lowering is expected to result in a robust CVD risk reduction.
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Affiliation(s)
- Kees Hovingh
- Academic Medical Center, Department of Vascular Medicine, Meibergdreef 9, Amsterdam, 1105 AZ, Netherlands
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