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Ghzaiel I, Zarrouk A, Essadek S, Martine L, Hammouda S, Yammine A, Ksila M, Nury T, Meddeb W, Tahri Joutey M, Mihoubi W, Caccia C, Leoni V, Samadi M, Acar N, Andreoletti P, Hammami S, Ghrairi T, Vejux A, Hammami M, Lizard G. Protective effects of milk thistle (Sylibum marianum) seed oil and α-tocopherol against 7β-hydroxycholesterol-induced peroxisomal alterations in murine C2C12 myoblasts: Nutritional insights associated with the concept of pexotherapy. Steroids 2022; 183:109032. [PMID: 35381271 DOI: 10.1016/j.steroids.2022.109032] [Citation(s) in RCA: 2] [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: 01/25/2022] [Revised: 03/15/2022] [Accepted: 03/31/2022] [Indexed: 12/11/2022]
Abstract
Peroxisomes play an important role in regulating cell metabolism and RedOx homeostasis. Peroxisomal dysfunctions favor oxidative stress and cell death. The ability of 7β-hydroxycholesterol (7β-OHC; 50 μM, 24 h), known to be increased in patients with age-related diseases such as sarcopenia, to trigger oxidative stress, mitochondrial and peroxisomal dysfunction was studied in murine C2C12 myoblasts. The capacity of milk thistle seed oil (MTSO, 100 μg/mL) as well as α-tocopherol (400 µM; reference cytoprotective agent) to counteract the toxic effects of 7β-OHC, mainly at the peroxisomal level were evaluated. The impacts of 7β-OHC, in the presence or absence of MTSO or α-tocopherol, were studied with complementary methods: measurement of cell density and viability, quantification of reactive oxygen species (ROS) production and transmembrane mitochondrial potential (ΔΨm), evaluation of peroxisomal mass as well as topographic, morphologic and functional peroxisomal changes. Our results indicate that 7β-OHC induces a loss of cell viability and a decrease of cell adhesion associated with ROS overproduction, alterations of mitochondrial ultrastructure, a drop of ΔΨm, and several peroxisomal modifications. In the presence of 7β-OHC, comparatively to untreated cells, important quantitative and qualitative peroxisomal modifications were also identified: a) a reduced number of peroxisomes with abnormal sizes and shapes, mainly localized in cytoplasmic vacuoles, were observed; b) the peroxisomal mass was decreased as indicated by lower protein and mRNA levels of the peroxisomal ABCD3 transporter; c) lower mRNA level of Pex5 involved in peroxisomal biogenesis as well as higher mRNA levels of Pex13 and Pex14, involved in peroxisomal biogenesis and/or pexophagy, was found; d) lower levels of ACOX1 and MFP2 enzymes, implicated in peroxisomal β-oxidation, were detected; e) higher levels of very-long-chain fatty acids, which are substrates of peroxisomal β-oxidation, were found. These different cytotoxic effects were strongly attenuated by MTSO, in the same range of order as with α-tocopherol. These findings underline the interest of MTSO and α-tocopherol in the prevention of peroxisomal damages (pexotherapy).
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Affiliation(s)
- Imen Ghzaiel
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France; Lab-NAFS 'Nutrition-Functional Food & Vascular Health', Faculty of Medicine, University of Monastir, LR12ES05, 5000 Monastir, Tunisia; Faculty of Sciences of Tunis, University Tunis-El Manar, 2092 Tunis, Tunisia
| | - Amira Zarrouk
- Lab-NAFS 'Nutrition-Functional Food & Vascular Health', Faculty of Medicine, University of Monastir, LR12ES05, 5000 Monastir, Tunisia; Faculty of Medicine, University of Sousse, 4000 Sousse, Tunisia.
| | - Soukaina Essadek
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France; Laboratory of Biochemistry, Neurosciences, Natural Resources and Environment, Faculty of Sciences & Techniques, University Hassan I, BP 577, 26000 Settat, Morocco
| | - Lucy Martine
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, 21065 Dijon, France
| | - Souha Hammouda
- Lab-NAFS 'Nutrition-Functional Food & Vascular Health', Faculty of Medicine, University of Monastir, LR12ES05, 5000 Monastir, Tunisia
| | - Aline Yammine
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France; Bioactive Molecules Research Laboratory, Doctoral School of Sciences and Technologies, Faculty of Sciences, Lebanese University, Fanar, Jdeidet P.O. Box 90656, Lebanon
| | - Mohamed Ksila
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France; Faculty of Sciences of Tunis, University Tunis-El Manar, 2092 Tunis, Tunisia
| | - Thomas Nury
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France
| | - Wiem Meddeb
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France
| | - Mounia Tahri Joutey
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France; Laboratory of Biochemistry, Neurosciences, Natural Resources and Environment, Faculty of Sciences & Techniques, University Hassan I, BP 577, 26000 Settat, Morocco
| | - Wafa Mihoubi
- Laboratoire de Biotechnologie Moléculaire des Eucaryotes, Centre de Biotechnologie de Sfax, B.P 1177, Université de Sfax, 3018 Sfax, Tunisia
| | - Claudio Caccia
- Laboratory of Clinical Chemistry, Hospitals of Desio, ASST-Brianza and Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Valerio Leoni
- Laboratory of Clinical Chemistry, Hospitals of Desio, ASST-Brianza and Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Mohammad Samadi
- LCPMC-A2, ICPM, Department of Chemistry, University Lorraine, Metz Technopôle, 57070 Metz, France
| | - Niyazi Acar
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, 21065 Dijon, France
| | - Pierre Andreoletti
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France
| | - Sonia Hammami
- Lab-NAFS 'Nutrition-Functional Food & Vascular Health', Faculty of Medicine, University of Monastir, LR12ES05, 5000 Monastir, Tunisia
| | - Taoufik Ghrairi
- Faculty of Sciences of Tunis, University Tunis-El Manar, 2092 Tunis, Tunisia
| | - Anne Vejux
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France
| | - Mohamed Hammami
- Lab-NAFS 'Nutrition-Functional Food & Vascular Health', Faculty of Medicine, University of Monastir, LR12ES05, 5000 Monastir, Tunisia
| | - Gérard Lizard
- Team 'Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism'EA7270/Inserm, University Bourgogne Franche-Comté, 21000 Dijon, France.
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2
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The Key Role of Peroxisomes in Follicular Growth, Oocyte Maturation, Ovulation, and Steroid Biosynthesis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:7982344. [PMID: 35154572 PMCID: PMC8831076 DOI: 10.1155/2022/7982344] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/04/2022] [Indexed: 02/06/2023]
Abstract
The absence of peroxisomes can cause disease in the human reproductive system, including the ovaries. The available peroxisomal gene-knockout female mouse models, which exhibit pathological changes in the ovary and reduced fertility, are listed in this review. Our review article provides the first systematic presentation of peroxisomal regulation and its possible functions in the ovary. Our immunofluorescence results reveal that peroxisomes are present in all cell types in the ovary; however, peroxisomes exhibit different numerical abundances and strong heterogeneity in their protein composition among distinct ovarian cell types. The peroxisomal compartment is strongly altered during follicular development and during oocyte maturation, which suggests that peroxisomes play protective roles in oocytes against oxidative stress and lipotoxicity during ovulation and in the survival of oocytes before conception. In addition, the peroxisomal compartment is involved in steroid synthesis, and peroxisomal dysfunction leads to disorder in the sexual hormone production process. However, an understanding of the cellular and molecular mechanisms underlying these physiological and pathological processes is lacking. To date, no effective treatment for peroxisome-related disease has been developed, and only supportive methods are available. Thus, further investigation is needed to resolve peroxisome deficiency in the ovary and eventually promote female fertility.
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Genetic reprogramming of remnant duodenum may contribute to type 2 diabetes improvement after Roux en-Y gastric bypass. Nutrition 2022; 99-100:111631. [DOI: 10.1016/j.nut.2022.111631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 12/31/2021] [Accepted: 02/07/2022] [Indexed: 11/22/2022]
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McCann MR, George De la Rosa MV, Rosania GR, Stringer KA. L-Carnitine and Acylcarnitines: Mitochondrial Biomarkers for Precision Medicine. Metabolites 2021; 11:51. [PMID: 33466750 PMCID: PMC7829830 DOI: 10.3390/metabo11010051] [Citation(s) in RCA: 140] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/11/2022] Open
Abstract
Biomarker discovery and implementation are at the forefront of the precision medicine movement. Modern advances in the field of metabolomics afford the opportunity to readily identify new metabolite biomarkers across a wide array of disciplines. Many of the metabolites are derived from or directly reflective of mitochondrial metabolism. L-carnitine and acylcarnitines are established mitochondrial biomarkers used to screen neonates for a series of genetic disorders affecting fatty acid oxidation, known as the inborn errors of metabolism. However, L-carnitine and acylcarnitines are not routinely measured beyond this screening, despite the growing evidence that shows their clinical utility outside of these disorders. Measurements of the carnitine pool have been used to identify the disease and prognosticate mortality among disorders such as diabetes, sepsis, cancer, and heart failure, as well as identify subjects experiencing adverse drug reactions from various medications like valproic acid, clofazimine, zidovudine, cisplatin, propofol, and cyclosporine. The aim of this review is to collect and interpret the literature evidence supporting the clinical biomarker application of L-carnitine and acylcarnitines. Further study of these metabolites could ultimately provide mechanistic insights that guide therapeutic decisions and elucidate new pharmacologic targets.
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Affiliation(s)
- Marc R. McCann
- The NMR Metabolomics Laboratory, Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Mery Vet George De la Rosa
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109, USA; (M.V.G.); (G.R.R.)
| | - Gus R. Rosania
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109, USA; (M.V.G.); (G.R.R.)
| | - Kathleen A. Stringer
- The NMR Metabolomics Laboratory, Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA;
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, University of Michigan, Ann Arbor, MI 48109, USA
- Michigan Center for Integrative Research in Critical Care, University of Michigan, Ann Arbor, MI 48109, USA
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Shen S, Faouzi S, Souquere S, Roy S, Routier E, Libenciuc C, André F, Pierron G, Scoazec JY, Robert C. Melanoma Persister Cells Are Tolerant to BRAF/MEK Inhibitors via ACOX1-Mediated Fatty Acid Oxidation. Cell Rep 2020; 33:108421. [DOI: 10.1016/j.celrep.2020.108421] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 07/10/2020] [Accepted: 11/01/2020] [Indexed: 12/21/2022] Open
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Quiñones W, Acosta H, Gonçalves CS, Motta MCM, Gualdrón-López M, Michels PAM. Structure, Properties, and Function of Glycosomes in Trypanosoma cruzi. Front Cell Infect Microbiol 2020; 10:25. [PMID: 32083023 PMCID: PMC7005584 DOI: 10.3389/fcimb.2020.00025] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 01/15/2020] [Indexed: 12/29/2022] Open
Abstract
Glycosomes are peroxisome-related organelles that have been identified in kinetoplastids and diplonemids. The hallmark of glycosomes is their harboring of the majority of the glycolytic enzymes. Our biochemical studies and proteome analysis of Trypanosoma cruzi glycosomes have located, in addition to enzymes of the glycolytic pathway, enzymes of several other metabolic processes in the organelles. These analyses revealed many aspects in common with glycosomes from other trypanosomatids as well as features that seem specific for T. cruzi. Their enzyme content indicates that T. cruzi glycosomes are multifunctional organelles, involved in both several catabolic processes such as glycolysis and anabolic ones. Specifically discussed in this minireview are the cross-talk between glycosomal metabolism and metabolic processes occurring in other cell compartments, and the importance of metabolite translocation systems in the glycosomal membrane to enable the coordination between the spatially separated processes. Possible mechanisms for metabolite translocation across the membrane are suggested by proteins identified in the organelle's membrane-homologs of the ABC and MCF transporter families-and the presence of channels as inferred previously from the detection of channel-forming proteins in glycosomal membrane preparations from the related parasite T. brucei. Together, these data provide insight in the way in which different parts of T. cruzi metabolism, although uniquely distributed over different compartments, are integrated and regulated. Moreover, this information reveals opportunities for the development of drugs against Chagas disease caused by these parasites and for which currently no adequate treatment is available.
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Affiliation(s)
- Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Héctor Acosta
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Camila Silva Gonçalves
- Laboratório de Ultraestrutura Celular Hertha Meyer, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Maria Cristina M Motta
- Laboratório de Ultraestrutura Celular Hertha Meyer, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Melisa Gualdrón-López
- Instituto Salud Global, Hospital Clinic-Universitat de Barcelona, and Institute for Health Sciences Trias i Pujol, Barcelona, Spain
| | - Paul A M Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, The University of Edinburgh, Edinburgh, United Kingdom
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Chen C, Wang H, Chen B, Chen D, Lu C, Li H, Qian Y, Tan Y, Weng H, Cai L. Pex11a deficiency causes dyslipidaemia and obesity in mice. J Cell Mol Med 2018; 23:2020-2031. [PMID: 30585412 PMCID: PMC6378206 DOI: 10.1111/jcmm.14108] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 11/20/2018] [Accepted: 12/03/2018] [Indexed: 11/29/2022] Open
Abstract
Peroxisomes play a central role in lipid metabolism. We previously demonstrated that Pex11a deficiency impairs peroxisome abundance and fatty acid β‐oxidation and results in hepatic triglyceride accumulation. The role of Pex11a in dyslipidaemia and obesity is investigated here with Pex11a knockout mice (Pex11a−/−). Metabolic phenotypes including tissue weight, glucose tolerance, insulin sensitivity, cholesterol levels, fatty acid profile, oxygen consumption, physical activity were assessed in wild‐type (WT) and Pex11a−/− fed with a high‐fat diet. Molecular changes and peroxisome abundance in adipose tissue were evaluated through qRT‐PCR, Western blotting, and Immunofluorescence. Pex11a−/− showed increased fat mass, decreased skeletal muscle, higher cholesterol levels, and more severely impaired glucose and insulin tolerance. Pex11a−/− consumed less oxygen, indicating a decrease in fatty acid oxidation, which is consistent with the accumulation of very long‐ and long‐chain fatty acids. Adipose palmitic acid (C16:0) levels were elevated in Pex11a−/−, which may be because of dramatically increased fatty acid synthase mRNA and protein levels. Furthermore, Pex11a deficiency increased ventricle size and macrophage infiltration, which are related to the reduced physical activity. These data demonstrate that Pex11a deficiency impairs physical activity and energy expenditure, decreases fatty acid β‐oxidation, increases de novo lipogenesis and results in dyslipidaemia and obesity.
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Affiliation(s)
- Congcong Chen
- Chinese-American Research Institute for Pediatrics & Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Chashan University-Town, Wenzhou, China.,Department of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China.,Department of Pharmacy, Jinhua Central Hospital, Jinhua, China
| | - Hongwei Wang
- Hepatobiliary and Pancreatic Surgery Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Bicheng Chen
- Hepatobiliary and Pancreatic Surgery Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Deyuan Chen
- Department of Pathology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Chaosheng Lu
- Chinese-American Research Institute for Pediatrics & Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Chashan University-Town, Wenzhou, China
| | - Haiyan Li
- Chinese-American Research Institute for Pediatrics & Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Chashan University-Town, Wenzhou, China
| | - Yan Qian
- Chinese-American Research Institute for Pediatrics & Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Chashan University-Town, Wenzhou, China
| | - Yi Tan
- Chinese-American Research Institute for Pediatrics & Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Chashan University-Town, Wenzhou, China.,Department of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China.,Pediatric Research Institute, Departments of Pediatrics, Radiation Oncology, Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky
| | - Huachun Weng
- Chinese-American Research Institute for Pediatrics & Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Chashan University-Town, Wenzhou, China
| | - Lu Cai
- Chinese-American Research Institute for Pediatrics & Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Chashan University-Town, Wenzhou, China.,Department of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China.,Pediatric Research Institute, Departments of Pediatrics, Radiation Oncology, Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky
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Feidantsis K, Pörtner HO, Vlachonikola E, Antonopoulou E, Michaelidis B. Seasonal Changes in Metabolism and Cellular Stress Phenomena in the Gilthead Sea Bream (Sparus aurata). Physiol Biochem Zool 2018; 91:878-895. [PMID: 29553887 DOI: 10.1086/697170] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Seasonal temperature changes may take organisms to the upper and lower limit of their thermal range, with respective variations in their biochemical and metabolic profile. To elucidate these traits, we investigated metabolic and antioxidant patterns in tissues of sea bream Sparus aurata during seasonal acclimatization for 1 yr in the field. Metabolic patterns were assessed by determining lactate dehydrogenase, citrate synthase, and β-hydroxyacyl CoA dehydrogenase activities, their kinetic properties and plasma levels of glucose, lactate, and triglycerides and tissue succinate levels. Oxidative stress was assessed by determining antioxidant enzymes superoxide dismutase, catalase, and glutathione reductase activities and levels of thiobarbituric acid reactive substances. Xanthine oxidase (XO) activity was determined as another source of reactive oxygen species (ROS) production. Furthermore, we studied the antiapoptotic protein indicator Bcl-2 and the apoptotic protein indicators Bax, Bad, ubiquitin, and caspase as well as indexes of autophagy (LC3B II/LC3B I and SQSTM1/p62) in the liver and the heart to identify possible relationships between oxidative stress and cell death. The results indicate clear seasonal metabolic patterns involving oxidative stress during summer as well as winter. During cold acclimatization, lipid oxidation is induced, while during increased temperatures, warm-induced metabolic activation and carbohydrate oxidation are observed. Thus, oxidative stress seems to be more prominent during warming because of the increased aerobic metabolism. The seasonal profile of apoptosis and XO as another source of ROS matches the results obtained in the laboratory and are interpreted within the framework of oxygen- and capacity-limited thermal tolerance.
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9
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Tang J, Fang Q, Shao R, Shen J, He J, Niu D, Lu L. Digital gene-expression profiling analysis of the fatty liver of Landes geese fed different supplemental oils. Gene 2018; 673:32-45. [DOI: 10.1016/j.gene.2018.05.122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/08/2018] [Accepted: 05/31/2018] [Indexed: 01/18/2023]
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10
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Wang H, Dolezal JM, Kulkarni S, Lu J, Mandel J, Jackson LE, Alencastro F, Duncan AW, Prochownik EV. Myc and ChREBP transcription factors cooperatively regulate normal and neoplastic hepatocyte proliferation in mice. J Biol Chem 2018; 293:14740-14757. [PMID: 30087120 DOI: 10.1074/jbc.ra118.004099] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/02/2018] [Indexed: 12/31/2022] Open
Abstract
Analogous to the c-Myc (Myc)/Max family of bHLH-ZIP transcription factors, there exists a parallel regulatory network of structurally and functionally related proteins with Myc-like functions. Two related Myc-like paralogs, termed MondoA and MondoB/carbohydrate response element-binding protein (ChREBP), up-regulate gene expression in heterodimeric association with the bHLH-ZIP Max-like factor Mlx. Myc is necessary to support liver cancer growth, but not for normal hepatocyte proliferation. Here, we investigated ChREBP's role in these processes and its relationship to Myc. Unlike Myc loss, ChREBP loss conferred a proliferative disadvantage to normal murine hepatocytes, as did the combined loss of ChREBP and Myc. Moreover, hepatoblastomas (HBs) originating in myc-/-, chrebp-/-, or myc-/-/chrebp-/- backgrounds grew significantly more slowly. Metabolic studies on livers and HBs in all three genetic backgrounds revealed marked differences in oxidative phosphorylation, fatty acid β-oxidation (FAO), and pyruvate dehydrogenase activity. RNA-Seq of livers and HBs suggested seven distinct mechanisms of Myc-ChREBP target gene regulation. Gene ontology analysis indicated that many transcripts deregulated in the chrebp-/- background encode enzymes functioning in glycolysis, the TCA cycle, and β- and ω-FAO, whereas those dysregulated in the myc-/- background encode enzymes functioning in glycolysis, glutaminolysis, and sterol biosynthesis. In the myc-/-/chrebp-/- background, additional deregulated transcripts included those involved in peroxisomal β- and α-FAO. Finally, we observed that Myc and ChREBP cooperatively up-regulated virtually all ribosomal protein genes. Our findings define the individual and cooperative proliferative, metabolic, and transcriptional roles for the "Extended Myc Network" under both normal and neoplastic conditions.
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Affiliation(s)
- Huabo Wang
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - James M Dolezal
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Sucheta Kulkarni
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Jie Lu
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Jordan Mandel
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | - Laura E Jackson
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC
| | | | | | - Edward V Prochownik
- From the Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC, .,the Pittsburgh Liver Center.,the Hillman Cancer Center of UPMC, and.,the Department of Microbiology and Molecular Genetics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15224
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11
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Abstract
Background: Peroxisomes are small cellular organelles that were almost ignored for years because they were believed to play only a minor role in cellular functions. However, it is now known that peroxisomes play an important role in regulating cellular proliferation and differentiation as well as in the modulation of inflammatory mediators. In addition, peroxisomes have broad effects on the metabolism of lipids, hormones, and xenobiotics. Through their effects on lipid metabolism, peroxisomes also affect cellular membranes and adipocyte formation, as well as insulin sensitivity, and peroxisomes play a role in aging and tumorigenesis through their effects on oxidative stress. Objective: To review genetically determined peroxisomal disorders, especially those that particularly affect the skin, and some recent information on the specific genetic defects that lead to some of these disorders. In addition, we present some of the emerging knowledge of peroxisomal proliferator activator receptors (PPARs) and how ligands for mese receptors modulate different peroxisomal functions. We also present information on how the discovery of PPARs, and the broad and diverse group of ligands that activate these members of the superfamily of nuclear binding transcription factors, has led to development of new drugs that modulate the function of peroxisomes. Conclusion: PPAR expression and ligand modulation within the skin have shown potential uses for these ligands in a number of inflammatory cutaneous disorders, including acne vulgaris, cutaneous disorders with barrier dysfunction, cutaneous effects of aging, and poor wound healing associated with altered signal transduction, as well as for side effects induced by the metabolic dysregulation of other drugs.
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Affiliation(s)
| | | | - Henry Skelton
- Laboratory Corporation of America, Herndon, Virginia
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12
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Abstract
Background: Peroxisomes are small cellular organelles that were almost ignored for years because they were believed to play only a minor role in cellular functions. However, it is now known that peroxisomes play an important role in regulating cellular proliferation and differentiation as well as in the modulation of inflammatory mediators. In addition, peroxisomes have broad effects on the metabolism of lipids, hormones, and xenobiotics. Through their effects on lipid metabolism, peroxisomes also affect cellular membranes and adipocyte formation, as well as insulin sensitivity, and peroxisomes play a role in aging and tumorigenesis through their effects on oxidative stress. Objective: To review genetically determined peroxisomal disorders, especially those that particularly affect the skin, and some recent information on the specific genetic defects that lead to some of these disorders. In addition, we present some of the emerging knowledge of peroxisomal proliferator activator receptors (PPARs) and how ligands for these receptors modulate different peroxisomal functions. We also present information on how the discovery of PPARs, and the broad and diverse group of ligands that activate these members of the superfamily of nuclear binding transcription factors, has led to development of new drugs that modulate the function of peroxisomes. Conclusion: PPAR expression and ligand modulation within the skin have shown potential uses for these ligands in a number of inflammatory cutaneous disorders, including acne vulgaris, cutaneous disorders with barrier dysfunction, cutaneous effects of aging, and poor wound healing associated with altered signal transduction, as well as for side effects induced by the metabolic dysregulation of other drugs.
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Petit VW, Rolland JL, Blond A, Cazevieille C, Djediat C, Peduzzi J, Goulard C, Bachère E, Dupont J, Destoumieux-Garzón D, Rebuffat S. A hemocyanin-derived antimicrobial peptide from the penaeid shrimp adopts an alpha-helical structure that specifically permeabilizes fungal membranes. Biochim Biophys Acta Gen Subj 2015; 1860:557-68. [PMID: 26708991 DOI: 10.1016/j.bbagen.2015.12.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/27/2015] [Accepted: 12/16/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND Hemocyanins are respiratory proteins with multiple functions. In diverse crustaceans hemocyanins can release histidine-rich antimicrobial peptides in response to microbial challenge. In penaeid shrimp, strictly antifungal peptides are released from the C-terminus of hemocyanins. METHODS The three-dimensional structure of the antifungal peptide PvHCt from Litopenaeus vannamei was determined by NMR. Its mechanism of action against the shrimp pathogen Fusarium oxysporum was investigated using immunochemistry, fluorescence and transmission electron microscopy. RESULTS PvHCt folded into an amphipathic α-helix in membrane-mimicking media and displayed a random conformation in aqueous environment. In contact with F. oxysporum, PvHCt bound massively to the surface of fungal hyphae without being imported into the cytoplasm. At minimal inhibitory concentrations, PvHCt made the fungal membrane permeable to SYTOX-green and fluorescent dextran beads of 4 kDa. Higher size beads could not enter the cytoplasm. Therefore, PvHCt likely creates local damages to the fungal membrane. While the fungal cell wall appeared preserved, gradual degeneration of the cytoplasm most often resulting in cell lysis was observed in fungal spores and hyphae. In the remaining fungal cells, PvHCt induced a protective response by the formation of daughter hyphae. CONCLUSION The massive accumulation of PvHCt at the surface of fungal hyphae and subsequent insertion into the plasma membrane disrupt its integrity as a permeability barrier, leading to disruption of internal homeostasis and fungal death. GENERAL SIGNIFICANCE The histidine-rich antimicrobial peptide PvHCt derived from shrimp hemocyanin is a strictly antifungal peptide, which adopts an amphipathic α-helical structure, and selectively binds to and permeabilizes fungal cells.
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Affiliation(s)
- Vanessa W Petit
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Jean-Luc Rolland
- Interactions Hôtes-Pathogènes-Environnements (IHPE), Ifremer, CNRS, UPVD, Université de Montpellier, UMR 5244, 34090 Montpellier, France
| | - Alain Blond
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Chantal Cazevieille
- COMET, Plateau de microscopie électronique, Plateforme Montpellier RIO Imaging, 34091 Montpellier, France
| | - Chakib Djediat
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Jean Peduzzi
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Christophe Goulard
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Evelyne Bachère
- Interactions Hôtes-Pathogènes-Environnements (IHPE), Ifremer, CNRS, UPVD, Université de Montpellier, UMR 5244, 34090 Montpellier, France
| | - Joëlle Dupont
- Institut de Systématique, Evolution, Biodiversité (ISYEB, UMR 7205), MNHN, Université Pierre et Marie Curie (UPMC), CNRS, Sorbonne Universités, 75005 Paris, France
| | - Delphine Destoumieux-Garzón
- Interactions Hôtes-Pathogènes-Environnements (IHPE), Ifremer, CNRS, UPVD, Université de Montpellier, UMR 5244, 34090 Montpellier, France
| | - Sylvie Rebuffat
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France.
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Weng H, Endo K, Li J, Kito N, Iwai N. Induction of peroxisomes by butyrate-producing probiotics. PLoS One 2015; 10:e0117851. [PMID: 25659146 PMCID: PMC4320100 DOI: 10.1371/journal.pone.0117851] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/05/2015] [Indexed: 01/04/2023] Open
Abstract
We previously found that peroxisomal biogenesis factor 11a (Pex11a) deficiency is associated with a reduction in peroxisome abundance and impaired fatty acid metabolism in hepatocytes, and results in steatosis. In the present study, we investigated whether butyrate induces Pex11a expression and peroxisome proliferation, and studied its effect on lipid metabolism. C57BL/6 mice fed standard chow or a high-fat diet (HFD) were treated with tributyrin, 4-phelybutyrate acid (4-PBA), or the butyrate-producing probiotics (Clostridium butyricum MIYAIRI 588 [CBM]) plus inulin (dietary fiber), and the body weight, white adipose tissue, serum triglycerides, mRNA expression, and peroxisome abundance were evaluated. Tributyrin or 4-PBA treatment significantly decreased body weight and increased hepatic mRNA expression of peroxisome proliferator-activated receptor-α (PPARα) and Pex11a. In addition, 4-PBA treatment increased peroxisome abundance and the expression of genes involved in peroxisomal fatty acid β-oxidation (acyl-coenzyme A oxidase 1 and hydroxysteroid [17-beta] dehydrogenase 4). CBM and inulin administration reduced adipose tissue mass and serum triglycerides, induced Pex11a, acyl-coenzyme A oxidase 1, and hydroxysteroid (17-beta) dehydrogenase 4 genes, and increased peroxisome abundance in mice fed standard chow or an HFD. In conclusion, elevation of butyrate availability (directly through administration of butyrate or indirectly via administration of butyrate-producing probiotics plus fiber) induces PPARα and Pex11a and the genes involved in peroxisomal fatty acid β-oxidation, increases peroxisome abundance, and improves lipid metabolism. These results may provide a new therapeutic strategy against hyperlipidemia and obesity.
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Affiliation(s)
- Huachun Weng
- Department of Genomic Medicine, Research Institute, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
- * E-mail: (HW); (NI)
| | - Kosuke Endo
- Department of Genomic Medicine, Research Institute, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Jiawei Li
- Department of Genomic Medicine, Research Institute, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Naoko Kito
- Department of Genomic Medicine, Research Institute, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Naoharu Iwai
- Department of Genomic Medicine, Research Institute, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
- * E-mail: (HW); (NI)
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15
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Weng H, Ji X, Endo K, Iwai N. Pex11a deficiency is associated with a reduced abundance of functional peroxisomes and aggravated renal interstitial lesions. Hypertension 2014; 64:1054-60. [PMID: 25113963 DOI: 10.1161/hypertensionaha.114.04094] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although proteinuria is known to be associated with the deterioration of chronic kidney disease, the molecular basis of this mechanism is not fully understood. We previously found that Pex11a deficiency was associated with a reduction of functional peroxisomes and impaired fatty acid metabolism in hepatocytes and resulted in steatosis. Proximal tubule cells are rich in peroxisomes. We assessed whether Pex11a deficiency might result in the derangement of peroxisome systems in proximal tubule cells and the aggravation of tubulointerstitial lesions in chronic kidney disease. Histological analyses showed that the number of functional peroxisomes in proximal tubule cells was reduced in Pex11a knockout (Pex11a(-/-)) mice. To clarify whether a decrease in the number of tubular peroxisomes might aggravate interstitial lesions, we assessed 2 models in which proximal tubule cells are overloaded with fatty acids (ie, deoxycorticosterone acetate and salt hypertension and the overload of fatty acid-bound albumin). Deoxycorticosterone acetate -salt-treated Pex11a(-/-) mice exhibited greater interstitial lesions than deoxycorticosterone acetate-salt-treated wild-type mice in terms of tubular lipid accumulation, blood pressure, urinary albumin, urinary N-acetyl-β-d-glucosaminidase, urinary 8-iso-prostane, and the histological evaluation of fibrosis and inflammation. An overload of fatty acid-bound albumin also resulted in more severe tubulointerstitial lesions in Pex11a(-/-) mice than in wild-type mice. Fenofibrate, a peroxisome proliferator-activated receptor-α agonist, restored the abundance of peroxisomes and reduced the tubulointerstitial lesions induced by deoxycorticosterone acetate-salt hypertension. In conclusion, our results indicate that proximal tubule peroxisomes play an important role in proteinuria-induced interstitial lesions. The activation of tubular peroxisomes might be an excellent therapeutic strategy against chronic kidney disease.
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Affiliation(s)
- Huachun Weng
- From the Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan.
| | - Xu Ji
- From the Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Kosuke Endo
- From the Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Naoharu Iwai
- From the Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan.
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17
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Association between the intrinsically disordered protein PEX19 and PEX3. PLoS One 2014; 9:e103101. [PMID: 25062251 PMCID: PMC4111287 DOI: 10.1371/journal.pone.0103101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/24/2014] [Indexed: 11/19/2022] Open
Abstract
In peroxisomes, peroxins (PEXs) 3 and 19 are the principal protein components of the machinery required for early peroxisomal biogenesis. For further insight into the interaction of PEX3 and PEX19, we used hydrogen exchange mass spectrometry to monitor conformational changes during complex formation between PEX3 and PEX19 in vitro. Our data showed that PEX19 remained highly flexible during interaction with PEX3. However, we could detect three changes, one each in the N-and C-terminus along with a small stretch in the middle of PEX19 (F64-L74) which became shielded from hydrogen exchange when interacting with PEX3. PEX3 became more protected from hydrogen exchange in the binding groove for PEX19 with only small changes elsewhere. Most likely the N-terminus of PEX19 initiates the binding to PEX3, and then subtle conformational changes in PEX3 affect the surface of the PEX3 molecule. PEX19 in turn, is stabilized by folding of a short helix and its C-terminal folding core permitting PEX19 to bind to PEX3 with higher affinity than just the N-terminal interaction allows. Thus within the cell, PEX3 is stabilized by PEX19 preventing PEX3 aggregation.
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Abstract
Peroxisomes are often dismissed as the cellular hoi polloi, relegated to cleaning up reactive oxygen chemical debris discarded by other organelles. However, their functions extend far beyond hydrogen peroxide metabolism. Peroxisomes are intimately associated with lipid droplets and mitochondria, and their ability to carry out fatty acid oxidation and lipid synthesis, especially the production of ether lipids, may be critical for generating cellular signals required for normal physiology. Here, we review the biology of peroxisomes and their potential relevance to human disorders including cancer, obesity-related diabetes, and degenerative neurologic disease.
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Nonalcoholic fatty liver disease: molecular pathways and therapeutic strategies. Lipids Health Dis 2013; 12:171. [PMID: 24209497 PMCID: PMC3827997 DOI: 10.1186/1476-511x-12-171] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 11/07/2013] [Indexed: 02/07/2023] Open
Abstract
Along with rising numbers of patients with metabolic syndrome, the prevalence of nonalcoholic fatty liver disease (NAFLD) has increased in proportion with the obesity epidemic. While there are no established treatments for NAFLD, current research is targeting new molecular mechanisms that underlie NAFLD and associated metabolic disorders. This review discusses some of these emerging molecular mechanisms and their therapeutic implications for the treatment of NAFLD. The basic research that has identified potential molecular targets for pharmacotherapy will be outlined.
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Weng H, Ji X, Naito Y, Endo K, Ma X, Takahashi R, Shen C, Hirokawa G, Fukushima Y, Iwai N. Pex11α deficiency impairs peroxisome elongation and division and contributes to nonalcoholic fatty liver in mice. Am J Physiol Endocrinol Metab 2013; 304:E187-96. [PMID: 23169785 DOI: 10.1152/ajpendo.00425.2012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hepatic triglyceride (TG) accumulation is considered to be a prerequisite for developing nonalcoholic fatty liver (NAFL). Peroxisomes have many important functions in lipid metabolism, including fatty acid β-oxidization. However, the pathogenic link between NAFL and peroxisome biogenesis remains unclear. To examine the molecular and physiological functions of the Pex11α gene, we disrupted this gene in mice. Body weights and hepatic TG concentrations in Pex11α(-/-) mice were significantly higher than those in wild-type (WT) mice fed a normal or a high-fat diet. Hepatic TG concentrations in fasted Pex11α(-/-) mice were significantly higher than those in fasted WT mice. Plasma TG levels increased at lower rates in Pex11α(-/-) mice than in WT mice after treatment with the lipoprotein lipase inhibitor tyloxapol. The number of peroxisomes was lower in the livers of Pex11α(-/-) mice than in those of WT mice. Ultrastructural analysis showed that small and regular spherically shaped peroxisomes were more prevalent in Pex11α(-/-) mice fed normal chow supplemented without or with fenofibrate. We observed a significantly higher ratio of empty peroxisomes containing only PMP70, a peroxisome membrane protein, but not catalase, a peroxisome matrix protein, in Pex11α(-/-) mice. The mRNA expression levels of peroxisomal fatty acid oxidation-related genes (ATP-binding cassette, subfamily D, member 2, and acyl-CoA thioesterase 3) were significantly higher in WT mice than those in Pex11α(-/-) mice under fed conditions. Our results demonstrate that Pex11α deficiency impairs peroxisome elongation and abundance and peroxisomal fatty acid oxidation, which contributes to increased lipid accumulation in the liver.
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Affiliation(s)
- Huachun Weng
- Department of Genomic Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
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21
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Sahoo S, Franzson L, Jonsson JJ, Thiele I. A compendium of inborn errors of metabolism mapped onto the human metabolic network. MOLECULAR BIOSYSTEMS 2013; 8:2545-58. [PMID: 22699794 DOI: 10.1039/c2mb25075f] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inborn errors of metabolism (IEMs) are hereditary metabolic defects, which are encountered in almost all major metabolic pathways occurring in man. Many IEMs are screened for in neonates through metabolomic analysis of dried blood spot samples. To enable the mapping of these metabolomic data onto the published human metabolic reconstruction, we added missing reactions and pathways involved in acylcarnitine (AC) and fatty acid oxidation (FAO) metabolism. Using literary data, we reconstructed an AC/FAO module consisting of 352 reactions and 139 metabolites. When this module was combined with the human metabolic reconstruction, the synthesis of 39 acylcarnitines and 22 amino acids, which are routinely measured, was captured and 235 distinct IEMs could be mapped. We collected phenotypic and clinical features for each IEM enabling comprehensive classification. We found that carbohydrate, amino acid, and lipid metabolism were most affected by the IEMs, while the brain was the most commonly affected organ. Furthermore, we analyzed the IEMs in the context of metabolic network topology to gain insight into common features between metabolically connected IEMs. While many known examples were identified, we discovered some surprising IEM pairs that shared reactions as well as clinical features but not necessarily causal genes. Moreover, we could also re-confirm that acetyl-CoA acts as a central metabolite. This network based analysis leads to further insight of hot spots in human metabolism with respect to IEMs. The presented comprehensive knowledge base of IEMs will provide a valuable tool in studying metabolic changes involved in inherited metabolic diseases.
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Abstract
Inborn errors of metabolism may impact on muscle and peripheral nerve. Abnormalities involve mitochondria and other subcellular organelles such as peroxisomes and lysosomes related to the turnover and recycling of cellular compartments. Treatable causes are β-oxidation defects producing progressive neuropathy; pyruvate dehydrogenase deficiency, porphyria, or vitamin B12 deficiency causing recurrent episodes of neuropathy or acute motor deficit mimicking Guillain-Barré syndrome. On the other hand, lysosomal (mucopolysaccharidosis, Gaucher and Fabry diseases), mitochondriopathic (mitochondrial or nuclear mutations or mDNA depletion), peroxisomal (adrenomyeloneuropathy, Refsum disease, sterol carrier protein-2 deficiency, cerebrotendinous xanthomatosis, α-methylacyl racemase deficiency) diseases are multisystemic disorders involving also the heart, liver, brain, retina, and kidney. Pathophysiology of most metabolic myopathies is related to the impairment of energy production or to abnormal production of reactive oxygen species (ROS). Main symptoms are exercise intolerance with myalgias, cramps and recurrent myoglobinuria or limb weakness associated with elevation of serum creatine kinase. Carnitine palmitoyl transferase deficiency, followed by acid maltase deficiency, and lipin deficiency, are the most common cause of isolated rhabdomyolysis. Metabolic myopathies are frequently associated to extra-neuromuscular disorders particularly involving the heart, liver, brain, retina, skin, and kidney.
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Affiliation(s)
- Adele D'Amico
- Molecular Medicine and Unit of Neuromuscular and Neurodegenerative Diseases, IRCCS-Children's Hospital Bambino Gesù, Rome, Italy
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23
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Translocation of solutes and proteins across the glycosomal membrane of trypanosomes; possibilities and limitations for targeting with trypanocidal drugs. Parasitology 2012; 140:1-20. [PMID: 22914253 DOI: 10.1017/s0031182012001278] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glycosomes are specialized peroxisomes found in all kinetoplastid organisms. The organelles are unique in harbouring most enzymes of the glycolytic pathway. Matrix proteins, synthesized in the cytosol, cofactors and metabolites have to be transported across the membrane. Recent research on Trypanosoma brucei has provided insight into how these translocations across the membrane occur, although many details remain to be elucidated. Proteins are imported by a cascade of reactions performed by specialized proteins, called peroxins, in which a cytosolic receptor with bound matrix protein inserts itself in the membrane to deliver its cargo into the organelle and is subsequently retrieved from the glycosome to perform further rounds of import. Bulky solutes, such as cofactors and acyl-CoAs, seem to be translocated by specific transporter molecules, whereas smaller solutes such as glycolytic intermediates probably cross the membrane through pore-forming channels. The presence of such channels is in apparent contradiction with previous results that suggested a low permeability of the glycosomal membrane. We propose 3 possible, not mutually exclusive, solutions for this paradox. Glycosomal glycolytic enzymes have been validated as drug targets against trypanosomatid-borne diseases. We discuss the possible implications of the new data for the design of drugs to be delivered into glycosomes.
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Joshi S, Agrawal G, Subramani S. Phosphorylation-dependent Pex11p and Fis1p interaction regulates peroxisome division. Mol Biol Cell 2012; 23:1307-15. [PMID: 22337771 PMCID: PMC3315806 DOI: 10.1091/mbc.e11-09-0782] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pex11p plays a conserved role in peroxisome division. Although Pex11p is phosphorylated, the exact role of this modification was either unknown or confusing. Phosphorylation of Pichia pastoris Pex11p at serine 173 occurs at the peroxisome and is necessary for its interaction with Fis1p, a key protein of the peroxisome division complex. Peroxisome division is regulated by the conserved peroxin Pex11p. In Saccharomyces cerevisiae (Sc), induction of the phosphoprotein ScPex11p coincides with peroxisome biogenesis. We show that the ScPex11p homologue in Pichia pastoris (PpPex11p) is phosphorylated at serine 173. PpPex11p expression and phosphorylation are induced in oleate and coordinated with peroxisome biogenesis. PpPex11p transits to peroxisomes via the endoplasmic reticulum (ER). PpPex11p is unstable and ER restricted gin pex3Δ and pex19Δ cells, which are impaired in peroxisomal membrane protein biogenesis. In oleate medium, the P. pastoris mutants pex11A (constitutively unphosphorylated; S173A) and pex11D (constitutively phosphorylated; S173D) exhibit juxtaposed elongated peroxisomes (JEPs) and hyperdivided forms, respectively, although protein levels remain unchanged. In contrast with ScPex11p, the ER-to-peroxisome translocation in P. pastoris is phosphorylation independent, and the phosphorylation occurs at the peroxisome. We show that PpPex11p interacts with the peroxisome fission machinery via PpFis1p and is regulated by phosphorylation because PpPex11p and PpPex11Dp interact more strongly with PpFis1p than PpPex11Ap. Neither PpPex11p nor PpFis1p is necessary for peroxisome division in methanol medium. We propose a model for the role of PpPex11p in the regulation of peroxisome division through a phosphorylation-dependent interaction with the fission machinery, providing novel insights into peroxisome morphogenesis.
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Affiliation(s)
- Saurabh Joshi
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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25
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Nakayama M, Sato H, Okuda T, Fujisawa N, Kono N, Arai H, Suzuki E, Umeda M, Ishikawa HO, Matsuno K. Drosophila carrying pex3 or pex16 mutations are models of Zellweger syndrome that reflect its symptoms associated with the absence of peroxisomes. PLoS One 2011; 6:e22984. [PMID: 21826223 PMCID: PMC3149631 DOI: 10.1371/journal.pone.0022984] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 07/10/2011] [Indexed: 11/19/2022] Open
Abstract
The peroxisome biogenesis disorders (PBDs) are currently difficult-to-treat multiple-organ dysfunction disorders that result from the defective biogenesis of peroxisomes. Genes encoding Peroxins, which are required for peroxisome biogenesis or functions, are known causative genes of PBDs. The human peroxin genes PEX3 or PEX16 are required for peroxisomal membrane protein targeting, and their mutations cause Zellweger syndrome, a class of PBDs. Lack of understanding about the pathogenesis of Zellweger syndrome has hindered the development of effective treatments. Here, we developed potential Drosophila models for Zellweger syndrome, in which the Drosophila pex3 or pex16 gene was disrupted. As found in Zellweger syndrome patients, peroxisomes were not observed in the homozygous Drosophila pex3 mutant, which was larval lethal. However, the pex16 homozygote lacking its maternal contribution was viable and still maintained a small number of peroxisome-like granules, even though PEX16 is essential for the biosynthesis of peroxisomes in humans. These results suggest that the requirements for pex3 and pex16 in peroxisome biosynthesis in Drosophila are different, and the role of PEX16 orthologs may have diverged between mammals and Drosophila. The phenotypes of our Zellweger syndrome model flies, such as larval lethality in pex3, and reduced size, shortened longevity, locomotion defects, and abnormal lipid metabolisms in pex16, were reminiscent of symptoms of this disorder, although the Drosophila pex16 mutant does not recapitulate the infant death of Zellweger syndrome. Furthermore, pex16 mutants showed male-specific sterility that resulted from the arrest of spermatocyte maturation. pex16 expressed in somatic cyst cells but not germline cells had an essential role in the maturation of male germline cells, suggesting that peroxisome-dependent signals in somatic cyst cells could contribute to the progression of male germ-cell maturation. These potential Drosophila models for Zellweger syndrome should contribute to our understanding of its pathology.
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Affiliation(s)
- Minoru Nakayama
- Genome and Drug Research Center, Tokyo University of Science, Noda, Chiba, Japan
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Hiroyasu Sato
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Takayuki Okuda
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Nao Fujisawa
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Nozomu Kono
- Graduate School of Pharmaceutical Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Hiroyuki Arai
- Graduate School of Pharmaceutical Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Emiko Suzuki
- Structural Biology Center, National Institute of Genetics, and Department of Genetics, The Graduate University for Advanced Studies, Mishima, Shizuoka, Japan
| | - Masato Umeda
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| | - Hiroyuki O. Ishikawa
- Genome and Drug Research Center, Tokyo University of Science, Noda, Chiba, Japan
| | - Kenji Matsuno
- Genome and Drug Research Center, Tokyo University of Science, Noda, Chiba, Japan
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- * E-mail:
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Paker AM, Sunness JS, Brereton NH, Speedie LJ, Albanna L, Dharmaraj S, Moser AB, Jones RO, Raymond GV. Docosahexaenoic acid therapy in peroxisomal diseases: results of a double-blind, randomized trial. Neurology 2010; 75:826-30. [PMID: 20805528 DOI: 10.1212/wnl.0b013e3181f07061] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Peroxisome assembly disorders are genetic disorders characterized by biochemical abnormalities, including low docosahexaenoic acid (DHA). The objective was to assess whether treatment with DHA supplementation would improve biochemical abnormalities, visual function, and growth in affected individuals. METHODS This was a randomized, double-blind, placebo-controlled trial conducted at a single center. Treatment groups received supplements of DHA (100 mg/kg per day). The primary outcome measures were the change from baseline in the visual function and physical growth during the 1 year follow-up period. RESULTS Fifty individuals were enrolled and randomized. Two were subsequently excluded from study analysis when it was determined that they had a single enzyme disorder of peroxisomal beta oxidation. Thirty-four returned for follow-up. Nine patients died during the trial of their disorder, and 5 others were lost to follow-up. DHA supplementation was well tolerated. There was no difference in the outcomes between the treated and untreated groups in biochemical function, electroretinogram, or growth. Improvements were seen in both groups in certain individuals. CONCLUSIONS DHA supplementation did not improve the visual function or growth of treated individuals with peroxisome assembly disorders. CLASSIFICATION OF EVIDENCE This interventional study provides Class II evidence that DHA supplementation did not improve the visual function or growth of treated individuals with peroxisome assembly disorders during an average of 1 year of follow-up in patients aged 1 to 144 months.
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Affiliation(s)
- A M Paker
- University of Texas Medical Branch, Galveston, TX, USA
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Yernaux C, Fransen M, Brees C, Lorenzen S, Michels PAM. Trypanosoma bruceiglycosomal ABC transporters: identification and membrane targeting. Mol Membr Biol 2009; 23:157-72. [PMID: 16754359 DOI: 10.1080/09687860500460124] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Trypanosomes contain unique peroxisome-like organelles designated glycosomes which sequester enzymes involved in a variety of metabolic processes including glycolysis. We identified three ABC transporters associated with the glycosomal membrane of Trypanosoma brucei. They were designated GAT1-3 for Glycosomal ABC Transporters. These polypeptides are so-called half-ABC transporters containing only one transmembrane domain and a single nucleotide-binding domain, like their homologues of mammalian and yeast peroxisomes. The glycosomal localization was shown by immunofluorescence microscopy of trypanosomes expressing fusion constructs of the transporters with Green Fluorescent Protein. By expression of fluorescent deletion constructs, the glycosome-targeting determinant of two transporters was mapped to different fragments of their respective primary structures. Interestingly, these fragments share a short sequence motif and contain adjacent to it one--but not the same--of the predicted six transmembrane segments of the transmembrane domain. We also identified the T. brucei homologue of peroxin PEX19, which is considered to act as a chaperonin and/or receptor for cytosolically synthesized proteins destined for insertion into the peroxisomal membrane. By using a bacterial two-hybrid system, it was shown that glycosomal ABC transporter fragments containing an organelle-targeting determinant can interact with both the trypanosomatid and human PEX19, despite their low overall sequence identity. Mutated forms of human PEX19 that lost interaction with human peroxisomal membrane proteins also did not bind anymore to the T. brucei glycosomal transporter. Moreover, fragments of the glycosomal transporter were targeted to the peroxisomal membrane when expressed in mammalian cells. Together these results indicate evolutionary conservation of the glycosomal/peroxisomal membrane protein import mechanism.
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Affiliation(s)
- Cédric Yernaux
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université catholique de Louvain, Brussels, Belgium
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Kovacs WJ, Tape KN, Shackelford JE, Wikander TM, Richards MJ, Fliesler SJ, Krisans SK, Faust PL. Peroxisome deficiency causes a complex phenotype because of hepatic SREBP/Insig dysregulation associated with endoplasmic reticulum stress. J Biol Chem 2008; 284:7232-45. [PMID: 19110480 DOI: 10.1074/jbc.m809064200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulation of hepatic cholesterol biosynthesis, lipogenesis, and insulin signaling intersect at the transcriptional level by control of SREBP and Insig genes. We previously demonstrated that peroxisome-deficient PEX2-/- mice activate SREBP-2 pathways but are unable to maintain normal cholesterol homeostasis. In this study, we demonstrate that oral bile acid treatment normalized hepatic and plasma cholesterol levels and hepatic cholesterol synthesis in early postnatal PEX2 mutants, but SREBP-2 and its target gene expressions remained increased. SREBP-2 pathway induction was also observed in neonatal and longer surviving PEX2 mutants, where hepatic cholesterol levels were normal. Abnormal expression patterns for SREBP-1c and Insig-2a, and novel regulation of Insig-2b, further demonstrate that peroxisome deficiency widely affects the regulation of related metabolic pathways. We have provided the first demonstration that peroxisome deficiency activates hepatic endoplasmic reticulum (ER) stress pathways, especially the integrated stress response mediated by PERK and ATF4 signaling. Our studies suggest a mechanism whereby ER stress leads to dysregulation of the endogenous sterol response mechanism and concordantly activates oxidative stress pathways. Several metabolic derangements in peroxisome-deficient PEX2-/- liver are likely to trigger ER stress, including perturbed flux of mevalonate metabolites, altered bile acid homeostasis, changes in fatty acid levels and composition, and oxidative stress.
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Affiliation(s)
- Werner J Kovacs
- Institute of Cell Biology, ETH Zürich, CH-8093 Zürich, Switzerland.
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Seong KY, Zhao X, Xu JR, Güldener U, Kistler HC. Conidial germination in the filamentous fungus Fusarium graminearum. Fungal Genet Biol 2008; 45:389-99. [PMID: 17950638 DOI: 10.1016/j.fgb.2007.09.002] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 09/03/2007] [Accepted: 09/04/2007] [Indexed: 11/16/2022]
Affiliation(s)
- Kye-Yong Seong
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, USA
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Sanders RJ, Ofman R, Dacremont G, Wanders RJA, Kemp S. Characterization of the human omega-oxidation pathway for omega-hydroxy-very-long-chain fatty acids. FASEB J 2008; 22:2064-71. [PMID: 18182499 DOI: 10.1096/fj.07-099150] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Very-long-chain fatty acids (VLCFAs) have long been known to be degraded exclusively in peroxisomes via beta-oxidation. A defect in peroxisomal beta-oxidation results in elevated levels of VLCFAs and is associated with the most frequent inherited disorder of the central nervous system white matter, X-linked adrenoleukodystrophy. Recently, we demonstrated that VLCFAs can also undergo omega-oxidation, which may provide an alternative route for the breakdown of VLCFAs. The omega-oxidation of VLCFA is initiated by CYP4F2 and CYP4F3B, which produce omega-hydroxy-VLCFAs. In this article, we characterized the enzymes involved in the formation of very-long-chain dicarboxylic acids from omega-hydroxy-VLCFAs. We demonstrate that very-long-chain dicarboxylic acids are produced via two independent pathways. The first is mediated by an as yet unidentified, microsomal NAD(+)-dependent alcohol dehydrogenase and fatty aldehyde dehydrogenase, which is encoded by the ALDH3A2 gene and is deficient in patients with Sjögren-Larsson syndrome. The second pathway involves the NADPH-dependent hydroxylation of omega-hydroxy-VLCFAs by CYP4F2, CYP4F3B, or CYP4F3A. Enzyme kinetic studies show that oxidation of omega-hydroxy-VLCFAs occurs predominantly via the NAD(+)-dependent route. Overall, our data demonstrate that in humans all enzymes are present for the complete conversion of VLCFAs to their corresponding very-long-chain dicarboxylic acids.
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Affiliation(s)
- Robert-Jan Sanders
- Academic Medical Center, University of Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam, The Netherlands
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Sato Y, Shibata H, Nakano H, Matsuzono Y, Kashiwayama Y, Kobayashi Y, Fujiki Y, Imanaka T, Kato H. Characterization of the interaction between recombinant human peroxin Pex3p and Pex19p: identification of TRP-104 IN Pex3p as a critical residue for the interaction. J Biol Chem 2008; 283:6136-44. [PMID: 18174172 DOI: 10.1074/jbc.m706139200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteins required for peroxisome biogenesis are termed peroxins. The peroxin Pex3p is a peroxisomal membrane protein (PMP), involved in peroxisomal membrane biogenesis. It acts as a docking receptor for another peroxin Pex19p, which is a specific carrier protein for newly synthesized PMPs. Here we have determined the physicochemical properties and binding manners of Pex3p-Pex19p interaction, in terms of the affinity, the stoichiometry, and the binding site in Pex3p. The cytosolic domain of human Pex3p was overproduced, using an Escherichia coli expression system and was highly purified by two chromatography steps. Gel filtration chromatography analyses and intrinsic tryptophan fluorescence titrations revealed that a one-to-one complex is formed between monomeric Pex3p and monomeric Pex19p. The tryptophan fluorescence spectrum of Pex3p showed a large 18-nm blue shift of the maximum emission wavelength by the binding of Pex19p. This result indicates that either one or two tryptophan residues of Pex3p (Trp-104 and Trp-224) are directly involved in binding to Pex19p. We investigated the binding activities of the wild-type and tryptophan mutants of Pex3p by pull-down assays and surface plasmon resonance analyses. As a result, the wild-type and the W104A and W104F mutants showed K(D) values of 3.4 nm, 1080 nm, and 66.2 nm, respectively. The affinity differences with mutation affected their peroxisome restoring activities in pex3 ZPG208 cells. These findings suggest that the indole ring of Trp-104 directly interacts with Pex19p to facilitate the specific peroxisomal translocation of the Pex19p-PMP complexes.
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Affiliation(s)
- Yasuhiko Sato
- Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, Japan
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Lockshon D, Surface LE, Kerr EO, Kaeberlein M, Kennedy BK. The sensitivity of yeast mutants to oleic acid implicates the peroxisome and other processes in membrane function. Genetics 2006; 175:77-91. [PMID: 17151231 PMCID: PMC1774995 DOI: 10.1534/genetics.106.064428] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The peroxisome, sole site of beta-oxidation in Saccharomyces cerevisiae, is known to be required for optimal growth in the presence of fatty acid. Screening of the haploid yeast deletion collection identified approximately 130 genes, 23 encoding peroxisomal proteins, necessary for normal growth on oleic acid. Oleate slightly enhances growth of wild-type yeast and inhibits growth of all strains identified by the screen. Nonperoxisomal processes, among them chromatin modification by H2AZ, Pol II mediator function, and cell-wall-associated activities, also prevent oleate toxicity. The most oleate-inhibited strains lack Sap190, a putative adaptor for the PP2A-type protein phosphatase Sit4 (which is also required for normal growth on oleate) and Ilm1, a protein of unknown function. Palmitoleate, the other main unsaturated fatty acid of Saccharomyces, fails to inhibit growth of the sap190delta, sit4delta, and ilm1delta strains. Data that suggest that oleate inhibition of the growth of a peroxisomal mutant is due to an increase in plasma membrane porosity are presented. We propose that yeast deficient in peroxisomal and other functions are sensitive to oleate perhaps because of an inability to effectively control the fatty acid composition of membrane phospholipids.
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Affiliation(s)
- Daniel Lockshon
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
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Guerra DG, Decottignies A, Bakker BM, Michels PAM. The mitochondrial FAD-dependent glycerol-3-phosphate dehydrogenase of Trypanosomatidae and the glycosomal redox balance of insect stages of Trypanosoma brucei and Leishmania spp. Mol Biochem Parasitol 2006; 149:155-69. [PMID: 16806528 DOI: 10.1016/j.molbiopara.2006.05.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 05/08/2006] [Accepted: 05/11/2006] [Indexed: 10/24/2022]
Abstract
The genes for the mitochondrial FAD-dependent glycerol-3-phosphate dehydrogenase were identified in Trypanosoma brucei and Leishmania major genomes. We have expressed the L. major gene in Saccharomyces cerevisiae and confirmed the subcellular localization and activity of the produced enzyme. Using cultured T. brucei procyclic and Leishmania mexicana promastigote cells with a permeabilized plasma membrane and containing intact glycosomes, it was shown that dihydroxyacetone phosphate is converted into pyruvate, and stimulates oxygen consumption, indicating that all components of the glycerol 3-phosphate/dihydoxyacetone phosphate shuttle between glycosomes and mitochondrion are present in these insect stages of both organisms. A computer model has been prepared for the energy and carbohydrate metabolism of these cells. It was used in an elementary mode analysis to get insight into the metabolic role of the shuttle in these insect-stage parasites. Our analysis suggests that the shuttle fulfils important roles for these organisms, albeit different from its well-known function in the T. brucei bloodstream form. It allows (1) a high yield of further metabolizable glycolytic products by decreasing the need to produce a secreted end product of glycosomal metabolism, succinate; (2) the consumption of glycerol and glycerol 3-phosphate derived from lipids; and (3) to keep the redox balance of the glycosome finely tuned due to a highly flexible and redundant system.
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Affiliation(s)
- Daniel G Guerra
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université catholique de Louvain, ICP-TROP 74.39, Avenue Hippocrate 74, B-1200 Brussels, Belgium
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Sanders RJ, Ofman R, Duran M, Kemp S, Wanders RJA. ω-Oxidation of Very Long-chain Fatty Acids in Human Liver Microsomes. J Biol Chem 2006; 281:13180-13187. [PMID: 16547005 DOI: 10.1074/jbc.m513481200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
X-linked adrenoleukodystrophy (X-ALD) is a severe neurodegenerative disorder biochemically characterized by elevated levels of very long-chain fatty acids (VLCFA). Excess levels of VLCFAs are thought to play an important role in the pathogenesis of X-ALD. Therefore, therapeutic approaches for X-ALD are focused on the reduction or normalization of VLCFAs. In this study, we investigated an alternative oxidation route for VLCFAs, namely omega-oxidation. The results described in this study show that VLCFAs are substrates for the omega-oxidation system in human liver microsomes. Moreover, VLCFAs were not only converted into omega-hydroxy fatty acids, but they were also further oxidized to dicarboxylic acids via cytochrome P450-mediated reactions. High sensitivity toward the specific P450 inhibitor 17-octadecynoic acid suggested that omega-hydroxylation of VLCFAs is catalyzed by P450 enzymes belonging to the CYP4A/F subfamilies. Studies with individually expressed human recombinant P450 enzymes revealed that two P450 enzymes, i.e. CYP4F2 and CYP4F3B, participate in the omega-hydroxylation of VLCFAs. Both enzymes belong to the cytochrome P450 4F subfamily and have a high affinity for VLCFAs. In summary, this study demonstrates that VLCFAs are substrates for the human omega-oxidation system, and for this reason, stimulation of the in vivo VLCFA omega-oxidation pathway may provide an alternative mode of treatment to reduce the levels of VLCFAs in patients with X-ALD.
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Affiliation(s)
- Robert-Jan Sanders
- Laboratory of Genetic Metabolic Diseases, University of Amsterdam, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
| | - Rob Ofman
- Laboratory of Genetic Metabolic Diseases, University of Amsterdam, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
| | - Marinus Duran
- Laboratory of Genetic Metabolic Diseases, University of Amsterdam, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
| | - Stephan Kemp
- Laboratory of Genetic Metabolic Diseases, University of Amsterdam, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Laboratory of Genetic Metabolic Diseases, University of Amsterdam, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands.
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Ofman R, Speijer D, Leen R, Wanders R. Proteomic analysis of mouse kidney peroxisomes: identification of RP2p as a peroxisomal nudix hydrolase with acyl-CoA diphosphatase activity. Biochem J 2006; 393:537-43. [PMID: 16185196 PMCID: PMC1360704 DOI: 10.1042/bj20050893] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 09/20/2005] [Accepted: 09/27/2005] [Indexed: 11/17/2022]
Abstract
Proteomic analysis of mouse kidney peroxisomes resulted in the identification of a novel nudix hydrolase designated RP2p, which is encoded by the D7RP2e gene. RP2p consists of 357 amino acids and contains two conserved domains: a nudix hydrolase domain and a CoA-binding domain. In addition, a PTS (peroxisomal targeting signal) type 1 (Ala-His-Leu) was found at the C-terminus. Analysis of the enzyme characteristics revealed that RP2p is a CoA diphosphatase with activity towards CoA, oxidized CoA and a wide range of CoA esters, including choloyl-CoA and branched-chain fatty-acyl-CoA esters. The enzymatic properties of RP2p indicate that at low substrate concentrations medium and long-chain fatty-acyl-CoA esters are the primary substrates. Enzyme activity was optimal at pH 9 or above, and required the presence of Mg2+ or Mn2+ ions. Subcellular fractionation studies revealed that all CoA diphosphatase activity in mouse kidney is restricted to peroxisomes.
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Affiliation(s)
- Rob Ofman
- *Department of Clinical Chemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
| | - Dave Speijer
- †Department of Medical Biochemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
| | - René Leen
- *Department of Clinical Chemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
| | - Ronald J. A. Wanders
- *Department of Clinical Chemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
- ‡Department of Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
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Lamhonwah AM, Ackerley CA, Tilups A, Edwards VD, Wanders RJ, Tein I. OCTN3 is a mammalian peroxisomal membrane carnitine transporter. Biochem Biophys Res Commun 2005; 338:1966-72. [PMID: 16288981 DOI: 10.1016/j.bbrc.2005.10.170] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2005] [Accepted: 10/25/2005] [Indexed: 11/29/2022]
Abstract
Carnitine is a zwitterion essential for the beta-oxidation of fatty acids. The role of the carnitine system is to maintain homeostasis in the acyl-CoA pools of the cell, keeping the acyl-CoA/CoA pool constant even under conditions of very high acyl-CoA turnover, thereby providing cells with a critical source of free CoA. Carnitine derivatives can be moved across intracellular barriers providing a shuttle mechanism between mitochondria, peroxisomes, and microsomes. We now demonstrate expression and colocalization of mOctn3, the intermediate-affinity carnitine transporter (Km 20 microM), and catalase in murine liver peroxisomes by TEM using immunogold labelled anti-mOctn3 and anti-catalase antibodies. We further demonstrate expression of hOCTN3 in control human cultured skin fibroblasts both by Western blotting and immunostaining analysis using our specific anti-mOctn3 antibody. In contrast with two peroxisomal biogenesis disorders, we show reduced expression of hOCTN3 in human PEX 1 deficient Zellweger fibroblasts in which the uptake of peroxisomal matrix enzymes is impaired but the biosynthesis of peroxisomal membrane proteins is normal, versus a complete absence of hOCTN3 in human PEX 19 deficient Zellweger fibroblasts in which both the uptake of peroxisomal matrix enzymes as well as peroxisomal membranes are deficient. This supports the localization of hOCTN3 to the peroxisomal membrane. Given the impermeability of the peroxisomal membrane and the key role of carnitine in the transport of different chain-shortened products out of peroxisomes, there appears to be a critical need for the intermediate-affinity carnitine/organic cation transporter, OCTN3, on peroxisomal membranes now shown to be expressed in both human and murine peroxisomes. This Octn3 localization is in keeping with the essential role of carnitine in peroxisomal lipid metabolism.
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Affiliation(s)
- Anne-Marie Lamhonwah
- Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada
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Ferrer I, Kapfhammer JP, Hindelang C, Kemp S, Troffer-Charlier N, Broccoli V, Callyzot N, Mooyer P, Selhorst J, Vreken P, Wanders RJA, Mandel JL, Pujol A. Inactivation of the peroxisomal ABCD2 transporter in the mouse leads to late-onset ataxia involving mitochondria, Golgi and endoplasmic reticulum damage. Hum Mol Genet 2005; 14:3565-77. [PMID: 16223892 DOI: 10.1093/hmg/ddi384] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
ATP-binding cassette (ABC) transporters facilitate unidirectional translocation of chemically diverse substances, ranging from peptides to lipids, across cell or organelle membranes. In peroxisomes, a subfamily of four ABC transporters (ABCD1 to ABCD4) has been related to fatty acid transport, because patients with mutations in ABCD1 (ALD gene) suffer from X-linked adrenoleukodystrophy (X-ALD), a disease characterized by an accumulation of very-long-chain fatty acids (VLCFAs). Inactivation in the mouse of the abcd1 gene leads to a late-onset neurodegenerative condition, comparable to the late-onset form of X-ALD [Pujol, A., Hindelang, C., Callizot, N., Bartsch, U., Schachner, M. and Mandel, J.L. (2002) Late onset neurological phenotype of the X-ALD gene inactivation in mice: a mouse model for adrenomyeloneuropathy. Hum. Mol. Genet., 11, 499-505.]. In the present work, we have generated and characterized a mouse deficient for abcd2, the closest paralog to abcd1. The main pathological feature in abcd2-/- mice is a late-onset cerebellar and sensory ataxia, with loss of cerebellar Purkinje cells and dorsal root ganglia cell degeneration, correlating with accumulation of VLCFAs in the latter cellular population. Axonal degeneration was present in dorsal and ventral columns in spinal cord. We have identified mitochondrial, Golgi and endoplasmic reticulum damage as the underlying pathological mechanism, thus providing evidence of a disturbed organelle cross-talk, which may be at the origin of the pathological cascade.
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Affiliation(s)
- Isidre Ferrer
- Institut de Neuropatologia, Hospital Universitari de Bellvitge, Department de Biologia Cel.lular i Anatomia Patologica, Facultat de Medicina, Universitat de Barcelona, Spain
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Larsen LN, Granlund L, Holmeide AK, Skattebøl L, Nebb HI, Bremer J. Sulfur-substituted and alpha-methylated fatty acids as peroxisome proliferator-activated receptor activators. Lipids 2005; 40:49-57. [PMID: 15825830 DOI: 10.1007/s11745-005-1359-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
FA with varying chain lengths and an alpha-methyl group and/or a sulfur in the beta-position were tested as peroxisome proliferator-activated receptor (PPAR)alpha, -delta(beta), and -gamma ligands by transient transfection in COS-1 cells using chimeric receptor expression plasmids, containing cDNAs encoding the ligand-binding domain of PPARalpha, -delta, and -gamma. For PPARalpha, an increasing activation was found with increasing chain length of the sulfur-substituted FA up to C14-S acetic acid (tetradecylthioacetic acid = TTA). The derivatives were poor, and nonsignificant, activators of PPARdelta. For PPARgamma, activation increased with increasing chain length up to C16-S acetic acid. A methyl group was introduced in the alpha-position of palmitic acid, TTA, EPA, DHA, cis9,trans11 CLA, and trans10,cis12 CLA. An increased activation of PPARalpha was obtained for the alpha-methyl derivatives compared with the unmethylated FA. This increase also resulted in increased expression of the two PPARalpha target genes acyl-CoA oxidase and liver FA-binding protein for alpha-methyl TTA, alpha-methyl EPA, and alpha-methyl DHA. Decreased or altered metabolism of these derivatives in the cells cannot be excluded. In conclusion, saturated FA with sulfur in the beta-position and increasing carbon chain length from C9-S acetic acid to C14-S acetic acid have increasing effects as activators of PPARalpha and -gamma in transfection assays. Furthermore, alpha-methyl FA derivatives of a saturated natural FA (palmitic acid), a sulfur-substituted FA (TTA), and PUFA (EPA, DHA, c9,t11 CLA, and t10,c12 CLA) are stronger PPARalpha activators than the unmethylated compounds.
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Affiliation(s)
- Laila N Larsen
- Institute of Basic Medical Sciences, Department of Biochemistry, University of Oslo, Norway.
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van Roermund CWT, de Jong M, IJlst L, van Marle J, Dansen TB, Wanders RJA, Waterham HR. The peroxisomal lumen in Saccharomyces cerevisiae is alkaline. J Cell Sci 2005; 117:4231-7. [PMID: 15316083 DOI: 10.1242/jcs.01305] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peroxisomes have a central function in lipid metabolism, including the beta-oxidation of various fatty acids. The products and substrates involved in the beta-oxidation have to cross the peroxisomal membrane, which previously has been demonstrated to constitute a closed barrier, implying the existence of specific transport mechanisms. Fatty acid transport across the yeast peroxisomal membrane may follow two routes: one for activated fatty acids, dependent on the peroxisomal ABC half transporter proteins Pxa1p and Pxa2p, and one for free fatty acids, which depends on the peroxisomal acyl-CoA synthetase Faa2p and the ATP transporter Ant1p. A proton gradient across the peroxisomal membrane as part of a proton motive force has been proposed to be required for proper peroxisomal function, but the nature of the peroxisomal pH has remained inconclusive and little is known about its generation. To determine the pH of Sacharomyces cerevisiae peroxisomes in vivo, we have used two different pH-sensitive yellow fluorescent proteins targeted to the peroxisome by virtue of a C-terminal SKL and found the peroxisomal matrix in wild-type cells to be alkaline (pH(per) 8.2), while the cytosolic pH was neutral (pH(cyt) 7.0). No Delta pH was present in ant1 Delta cells, indicating that the peroxisomal pH is regulated in an ATP-dependent way and suggesting that Ant1p activity is directly involved in maintenance of the peroxisomal pH. Moreover, we found a high peroxisomal pH of >8.6 in faa2 Delta cells, while the peroxisomal pH remained 8.1+/-0.2 in pxa2 Delta cells. Our combined results suggest that the proton gradient across the peroxisomal membrane is dependent on Ant1p activity and required for the beta-oxidation of medium chain fatty acids.
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Affiliation(s)
- Carlo W T van Roermund
- Department of Clinical Chemistry, University of Amsterdam, Academic Medical Centre, PO Box 22700, 1100 DE, Amsterdam, The Netherlands.
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Brocard CB, Boucher KK, Jedeszko C, Kim PK, Walton PA. Requirement for Microtubules and Dynein Motors in the Earliest Stages of Peroxisome Biogenesis. Traffic 2005; 6:386-95. [PMID: 15813749 DOI: 10.1111/j.1600-0854.2005.00283.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Our aim was to determine the role of microtubules in the biogenesis of peroxisomes. Fusion experiments between human PEX16- and PEX1-mutant cells in the presence of nocodazol implied that microtubules were not required for import of proteins into the peroxisomal matrix after cell fusion complementation. We further studied the importance of microtubules in the early stages of peroxisome biogenesis following the microinjection complementation of PEX16-mutant cells. In the absence of nocodazol, nuclear microinjection of plasmids expressing EGFP-SKL and Pex16p in PEX16-mutant cells resulted in the accumulation of EGFP-SKL into newly formed peroxisomes. However, pretreatment of the cells with nocodazol, prior to microinjection, resulted in the inhibition of complementation of the PEX16 mutant and the cytosolic location of the EGFP-SKL. In addition, coexpression of a dominant-negative CC1 subunit of the dynein/dynactin motor complex resulted in the inability to complement PEX16-mutant cells. Both of these treatments resulted in the cytosolic localization of expressed Pex16p. Our results demonstrate that the formation of peroxisomes via the preperoxisomal compartment is dependent upon microtubules and minus-end-directed motor proteins and that the inhibition described above occurs at a step that precedes the association of Pex16p with the vesicles that would otherwise become the peroxisomes.
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Affiliation(s)
- Cécile B Brocard
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada N6A 5C1
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Moyersoen J, Choe J, Fan E, Hol WGJ, Michels PAM. Biogenesis of peroxisomes and glycosomes: trypanosomatid glycosome assembly is a promising new drug target. FEMS Microbiol Rev 2005; 28:603-43. [PMID: 15539076 DOI: 10.1016/j.femsre.2004.06.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 06/14/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022] Open
Abstract
In trypanosomatids (Trypanosoma and Leishmania), protozoa responsible for serious diseases of mankind in tropical and subtropical countries, core carbohydrate metabolism including glycolysis is compartmentalized in peculiar peroxisomes called glycosomes. Proper biogenesis of these organelles and the correct sequestering of glycolytic enzymes are essential to these parasites. Biogenesis of glycosomes in trypanosomatids and that of peroxisomes in other eukaryotes, including the human host, occur via homologous processes involving proteins called peroxins, which exert their function through multiple, transient interactions with each other. Decreased expression of peroxins leads to death of trypanosomes. Peroxins show only a low level of sequence conservation. Therefore, it seems feasible to design compounds that will prevent interactions of proteins involved in biogenesis of trypanosomatid glycosomes without interfering with peroxisome formation in the human host cells. Such compounds would be suitable as lead drugs against trypanosomatid-borne diseases.
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Affiliation(s)
- Juliette Moyersoen
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université Catholique de Louvain, ICP-TROP 74.39, Avenue Hippocrate 74, B-1200 Brussels, Belgium
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Dhaunsi GS, Al-Essa M, Muawad W, Srivastava BS, Rashwan N. Very-long-chain fatty acids activate lysosomal hydrolases in neonatal human skin tissue. Med Princ Pract 2005; 14 Suppl 1:92-7. [PMID: 16103719 DOI: 10.1159/000086190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Accepted: 03/21/2005] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The aim of this study was to examine the in vitro effect of peroxisomal dysfunction on lysosomal enzymes, the autophagic machinery in the cell, in order to understand the mechanisms of pathogenesis of peroxisomal disorders. MATERIALS AND METHODS Foreskin samples were obtained immediately after circumcision of 1- to 2-day-old infants at the Maternity Hospital, Kuwait. Skin tissues were cleaned, cut into slices of 1-2 mm2 in size and treated with lignoceric acid (1-20 microg/ml), a very-long-chain fatty acid (VLCFA), in the presence or absence of 1-5 mM aminotriazole (ATZ). A battery of lysosomal enzymes were assayed following treatment of dermal tissue with VLCFA or ATZ. RESULTS Treatment of skin slices with lignoceric acid significantly increased (p < 0.001) the enzymic activities of acid lipase, acid phosphatase, alpha-glucosidase, alpha-galactosidase, N-acetyl-alpha-D-glucosaminidase (NAGA) and N-acetyl-alpha-D-galactosaminidase (NAGTA). ATZ (1-5 mM), an inhibitor of key peroxi somal enzyme catalase, also markedly increased the enzymic activities of acid phosphatase, alpha-glucosidase (23%) and alpha-galactosidase (18%) without any significant effect on NAGA or NAGTA. Western blot analysis further revealed that both VLCFA and ATZ significantly increased the protein expression of lysosomal enzymes, beta-galactosidase and beta-glucuronidase. CONCLUSION Experimen tal dysfunction of peroxisomes mimicked by elevated VLCFA or ATZ-mediated catalase inhibition significantly increased the activities of lysosomal hydrolases in human dermal tissue, suggesting that activation of the lysosomal system could be one of the factors responsible for cellular damage during pathogenesis of peroxisomal diseases.
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Affiliation(s)
- Gursev S Dhaunsi
- Department of Pediatrics, Faculty of Medicine, Kuwait University, Kuwait.
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Shibata H, Kashiwayama Y, Imanaka T, Kato H. Domain architecture and activity of human Pex19p, a chaperone-like protein for intracellular trafficking of peroxisomal membrane proteins. J Biol Chem 2004; 279:38486-94. [PMID: 15252024 DOI: 10.1074/jbc.m402204200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pex19p is a peroxin involved in peroxisomal membrane biogenesis and probably functions as a chaperone and/or soluble receptor specific for cargo peroxisomal membrane proteins (PMPs). To elucidate the functional constituents of Pex19p in terms of the protein structure, we investigated its domain architecture and binding affinity toward various PMPs and peroxins. The human Pex19p cDNA was overexpressed in Escherichia coli, and a highly purified sample of the Pex19p protein was prepared. When PMP22 was synthesized by cell-free translation in the presence of Pex19p, the PMP22 bound to Pex19p was soluble, whereas PMP22 alone was insoluble. This observation shows that Pex19p plays a role in capturing PMP and maintaining its solubility. In a similar manner, Pex19p was bound to PMP70 and Pex16p as well as the Pex3p soluble fragment. Limited proteolysis analyses revealed that Pex19p consists of the C-terminal core domain flanking the flexible N-terminal region. Separation of Pex19p into its N- and C-terminal halves abolished interactions with PMP22, PMP70, and Pex16p. In contrast, the flexible N-terminal half of Pex19p was bound to the Pex3p soluble fragment, suggesting that the binding mode of Pex3p toward Pex19p differs from that of other PMPs. This idea is supported by our detection of the Pex19p-Pex3p-PMP22 ternary complex.
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Affiliation(s)
- Hiroyuki Shibata
- Kinetic Crystallography Research Team, Membrane Dynamics Research Group, RIKEN, Harima Institute at SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan
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Hargrove JL, Greenspan P, Hartle DK. Nutritional significance and metabolism of very long chain fatty alcohols and acids from dietary waxes. Exp Biol Med (Maywood) 2004; 229:215-26. [PMID: 14988513 DOI: 10.1177/153537020422900301] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Very long chain fatty alcohols obtained from plant waxes and beeswax have been reported to lower plasma cholesterol in humans. This review discusses nutritional or regulatory effects produced by wax esters or aliphatic acids and alcohols found in unrefined cereal grains, beeswax, and many plant-derived foods. Reports suggest that 5-20 mg per day of mixed C24-C34 alcohols, including octacosanol and triacontanol, lower low-density lipoprotein (LDL) cholesterol by 21%-29% and raise high-density lipoprotein cholesterol by 8%-15%. Wax esters are hydrolyzed by a bile salt-dependent pancreatic carboxyl esterase, releasing long chain alcohols and fatty acids that are absorbed in the gastrointestinal tract. Studies of fatty alcohol metabolism in fibroblasts suggest that very long chain fatty alcohols, fatty aldehydes, and fatty acids are reversibly inter-converted in a fatty alcohol cycle. The metabolism of these compounds is impaired in several inherited human peroxisomal disorders, including adrenoleukodystrophy and Sjögren-Larsson syndrome. Reports on dietary management of these diseases confirm that very long chain fatty acids (VLCFA) are normal constituents of the human diet and are synthesized endogenously. Concentrations of VLCFA in blood plasma increase during fasting and when children are placed on ketogenic diets to suppress seizures. Existing data support the hypothesis that VLCFA exert regulatory roles in cholesterol metabolism in the peroxisome and also alter LDL uptake and metabolism.
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Affiliation(s)
- James L Hargrove
- Department of Foods and Nutrition, University of Georgia, Athens, Georgia 30602, USA.
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Quiñones W, Urbina JA, Dubourdieu M, Luis Concepción J. The glycosome membrane of Trypanosoma cruzi epimastigotes: protein and lipid composition. Exp Parasitol 2004; 106:135-49. [PMID: 15172221 DOI: 10.1016/j.exppara.2004.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2003] [Revised: 11/26/2003] [Accepted: 03/19/2004] [Indexed: 11/18/2022]
Abstract
Highly purified glycosomes from Trypanosoma cruzi epimastigotes were obtained by differential centrifugation and isopycnic ultracentrifugation. Glycosomal membranes, produced by carbonate treatment of purified glycosomes, exhibited about eight main protein bands and eight minor ones. Essentially the same protein pattern was observed in the detergent-rich fraction of a Triton X-114 fractionation of whole glycosomes, indicating that most of the membrane-bound polypeptides were highly hydrophobic. The orientation of these proteins was studied by in situ labelling followed by limited pronase hydrolysis of intact glycosomes. Three glycosome membrane proteins were characterized as peripheral by comparing the protein bands patterns of membrane fractions obtained by different treatments. Noteworthy membrane polypeptides were: (1) a peripheral 75k Da membrane protein, oriented towards the cytosol, which was the most abundant glycosomal membrane protein in exponentially growing epimastigotes but was essentially absent in stationary phase cells; (2) a pair of integral membrane proteins with molecular masses in the range of 85-100 kDa, which were only present in stationary phase cells; (3) a heme-containing 36k Da protein, strongly associated to the membrane, present in both growth phases; (4) a very immunogenic 41k Da integral membrane polypeptide, oriented towards the cytosol. The lipid composition of the glycosomal membranes was also investigated. The distribution of phospholipid species in glycosomes and glycosomal membranes was very similar to that of whole cells, with phosphatidyl-ethanolamine, phosphatidyl-choline, and phosphatidyl-serine as main components and smaller proportions of sphingomyelin and with phosphatidyl-inositol. On the other hand, glycosomes were enriched in endogenous sterols (ergosterol, 24-ethyl-5,7,22-cholesta-trien-3beta-ol), and precursors, when compared with whole cells, a finding consistent with the proposal that these organelles are involved in the de novo biosynthesis of sterols in trypanosomatids.
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Affiliation(s)
- Wilfredo Quiñones
- Unidad de Bioquímica de Parásitos, Centro de Ingeniería Genética, Facultad de Ciencias, Universidad de Los Andes, Apartado 38, Mérida, Venezuela
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Abstract
Peroxisome biogenesis conceptually consists of the (a) formation of the peroxisomal membrane, (b) import of proteins into the peroxisomal matrix and (c) proliferation of the organelles. Combined genetic and biochemical approaches led to the identification of 25 PEX genes-encoding proteins required for the biogenesis of peroxisomes, so-called peroxins. Peroxisomal matrix and membrane proteins are synthesized on free ribosomes in the cytosol and posttranslationally imported into the organelle in an unknown fashion. The protein import into the peroxisomal matrix and the targeting and insertion of peroxisomal membrane proteins is performed by distinct machineries. At least three peroxins have been shown to be involved in the topogenesis of peroxisomal membrane proteins. Elaborate peroxin complexes form the machinery which in a concerted action of the components transports folded, even oligomeric matrix proteins across the peroxisomal membrane. The past decade has significantly improved our knowledge of the involvement of certain peroxins in the distinct steps of the import process, like cargo recognition, docking of cargo-receptor complexes to the peroxisomal membrane, translocation, and receptor recycling. This review summarizes our knowledge of the functional role the known peroxins play in the biogenesis and maintenance of peroxisomes. Ideas on the involvement of preperoxisomal structures in the biogenesis of the peroxisomal membrane are highlighted and special attention is paid to the concept of cargo protein aggregation as a presupposition for peroxisomal matrix protein import.
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Affiliation(s)
- J H Eckert
- Institut für Physiologische Chemie, Medizinische Fakultät, Ruhr-Universität Bochum, 44780 Bochum, Germany
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Shechter I, Dai P, Huo L, Guan G. IDH1 gene transcription is sterol regulated and activated by SREBP-1a and SREBP-2 in human hepatoma HepG2 cells: evidence that IDH1 may regulate lipogenesis in hepatic cells. J Lipid Res 2003; 44:2169-80. [PMID: 12923220 DOI: 10.1194/jlr.m300285-jlr200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mRNA level for cytosolic NADP-dependent isocitrate dehydrogenase (IDH1) increases 2.3-fold, and enzyme activity of NADP-isocitrate dehydrogenase (IDH) 63%, in sterol-deprived HepG2 cells. The mRNA levels of the NADP- and NAD-dependent mitochondrial enzymes show limited or lack of regulation under the same conditions. Nucleotide sequences that are required, and sufficient, for the sterol regulation of transcription are located within a 67 bp region of an IDH1-secreted alkaline phosphatase promoter-reporter gene. The IDH1 promoter is fully activated by the expression of SREBP-1a in the cells and, to a lesser degree, by that of SREBP-2. A 5'-end truncation of 23 bp containing a CAAT and a GC-Box results in 6.5% residual activity. The promoter region involved in the activation by the sterol regulatory element binding proteins (SREBPs) is located at nucleotides -44 to -25. Mutagenesis analysis identified within this region the IDH1-SRE sequence element GTGGGCTGAG, which binds the SREBPs. Similar to the promoter activation, electrophoretic mobility shifts of probes containing the IDH1-SRE element exhibit preferential binding to SREBP-1a, as compared with SREBP-2. These results indicate that IDH1 activity is coordinately regulated with the cholesterol and fatty acid biosynthetic pathways and suggest that it is the source for the cytosolic NADPH required by these pathways.
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Affiliation(s)
- Ishaiahu Shechter
- Department of Surgery, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA.
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Eckert JH, Johnsson N. Pex10p links the ubiquitin conjugating enzyme Pex4p to the protein import machinery of the peroxisome. J Cell Sci 2003; 116:3623-34. [PMID: 12876220 DOI: 10.1242/jcs.00678] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The protein import machinery of the peroxisome consists of many proteins, collectively called the peroxins. By applying the split-ubiquitin technique we systematically tested the pair-wise interactions between the Nub- and Cub-labeled peroxins for the first time in the living cells of the yeast Saccharomyces cerevisiae. We found that Pex10p plays a central role in the protein interaction network by connecting the ubiquitin conjugation enzyme Pex4p to the other members of the protein import machinery. A yeast strain harboring a deletion of PEX3 enabled us to estimate the influence of the peroxisomal membrane on the formation of a subset of the investigated protein-protein interactions.
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Affiliation(s)
- Jörg H Eckert
- Ruhr-Universität Bochum, Institut für Physiologische Chemie, Medizinische Fakultät, 44780 Bochum, Germany
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Functional genetics of Yarrowia lipolytica. ACTA ACUST UNITED AC 2003. [DOI: 10.1007/3-540-37003-x_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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Abstract
The 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors, more commonly known as statins, are a class of drug widely used for the treatment of hypercholesterolaemia in patients with established cardiovascular disease as well as those at high risk of developing atherosclerosis. Their predominant action is to reduce circulating levels of low-density lipoprotein (LDL) cholesterol; to a smaller degree, they also increase high-density lipoprotein (HDL) cholesterol and reduce triglyceride concentrations. In recent years, however, there has been an increasing body of evidence that their effects on lipid profile cannot fully account for their cardiovascular protective actions: their beneficial effects are too rapid to be easily explained by their relatively slow effects on atherogenesis and too large to be accounted for by their relatively small effects on plaque regression. Experimental models have revealed that statins exert a variety of other cardiovascular effects, which would be predicted to be of clinical benefit: they possess anti-inflammatory properties, as evidenced by their ability to reduce the accumulation of inflammatory cells in atherosclerotic plaques; they inhibit vascular smooth muscle cell proliferation, a key event in atherogenesis; they inhibit platelet function, thereby limiting both atherosclerosis and superadded thrombosis; and they improve vascular endothelial function, largely through augmentation of nitric oxide (NO) generation. The relative importance of the lipid- and non-lipid-related effects of the statins in the clinical situation remains the subject of much continuing research.
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Affiliation(s)
- Anthony S Wierzbicki
- Department of Chemical Pathology, GKT School of Medicine, King's College London, London, UK
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