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Miura D, Tsurigami R, Kato H, Wariishi H, Shimizu M. Pathway crosstalk between the central metabolic and heme biosynthetic pathways in Phanerochaete chrysosporium. Appl Microbiol Biotechnol 2024; 108:37. [PMID: 38183476 PMCID: PMC10771590 DOI: 10.1007/s00253-023-12846-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/28/2023] [Accepted: 10/03/2023] [Indexed: 01/08/2024]
Abstract
A comprehensive analysis to survey heme-binding proteins produced by the white-rot fungus Phanerochaete chrysosporium was achieved using a biotinylated heme-streptavidin beads system. Mitochondrial citrate synthase (PcCS), glyceraldehyde 3-phosphate dehydrogenase (PcGAPDH), and 2-Cys thioredoxin peroxidase (mammalian HBP23 homolog) were identified as putative heme-binding proteins. Among these, PcCS and PcGAPDH were further characterized using heterologously expressed recombinant proteins. Difference spectra of PcCS titrated with hemin exhibited an increase in the Soret absorbance at 414 nm, suggesting that the axial ligand of the heme is a His residue. The activity of PcCS was strongly inhibited by hemin with Ki oxaloacetate of 8.7 μM and Ki acetyl-CoA of 5.8 μM. Since the final step of heme biosynthesis occurred at the mitochondrial inner membrane, the inhibition of PcCS by heme is thought to be a physiological event. The inhibitory mode of the heme was similar to that of CoA analogues, suggesting that heme binds to PcCS at His347 at the AcCoA-CoA binding site, which was supported by the homology model of PcCS. PcGAPDH was also inhibited by heme, with a lower concentration than that for PcCS. This might be caused by the different location of these enzymes. From the integration of these phenomena, it was concluded that metabolic regulations by heme in the central metabolic and heme synthetic pathways occurred in the mitochondria and cytosol. This novel pathway crosstalk between the central metabolic and heme biosynthetic pathways, via a heme molecule, is important in regulating the metabolic balance (heme synthesis, ATP synthesis, flux balance of the tricarboxylic acid (TCA) cycle and cellular redox balance (NADPH production) during fungal aromatic degradation. KEY POINTS: • A comprehensive survey of heme-binding proteins in P. chrysosporium was achieved. • Several heme-binding proteins including CS and GAPDH were identified. • A novel metabolic regulation by heme in the central metabolic pathways was found.
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Affiliation(s)
- Daisuke Miura
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8566, Japan.
| | - Ryoga Tsurigami
- Faculty of Agriculture, Meijo University, Nagoya, Aichi, 468-8502, Japan
| | - Hiroyuki Kato
- Faculty of Agriculture, Meijo University, Nagoya, Aichi, 468-8502, Japan
| | - Hiroyuki Wariishi
- Faculty of Arts and Science, Kyushu University, Fukuoka, Fukuoka, 819-0395, Japan
| | - Motoyuki Shimizu
- Faculty of Agriculture, Meijo University, Nagoya, Aichi, 468-8502, Japan.
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2
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Dunaway LS, Loeb SA, Petrillo S, Tolosano E, Isakson BE. Heme metabolism in nonerythroid cells. J Biol Chem 2024; 300:107132. [PMID: 38432636 PMCID: PMC10988061 DOI: 10.1016/j.jbc.2024.107132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/31/2024] [Accepted: 02/23/2024] [Indexed: 03/05/2024] Open
Abstract
Heme is an iron-containing prosthetic group necessary for the function of several proteins termed "hemoproteins." Erythrocytes contain most of the body's heme in the form of hemoglobin and contain high concentrations of free heme. In nonerythroid cells, where cytosolic heme concentrations are 2 to 3 orders of magnitude lower, heme plays an essential and often overlooked role in a variety of cellular processes. Indeed, hemoproteins are found in almost every subcellular compartment and are integral in cellular operations such as oxidative phosphorylation, amino acid metabolism, xenobiotic metabolism, and transcriptional regulation. Growing evidence reveals the participation of heme in dynamic processes such as circadian rhythms, NO signaling, and the modulation of enzyme activity. This dynamic view of heme biology uncovers exciting possibilities as to how hemoproteins may participate in a range of physiologic systems. Here, we discuss how heme is regulated at the level of its synthesis, availability, redox state, transport, and degradation and highlight the implications for cellular function and whole organism physiology.
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Affiliation(s)
- Luke S Dunaway
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Skylar A Loeb
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Sara Petrillo
- Deptartment Molecular Biotechnology and Health Sciences and Molecular Biotechnology Center "Guido Tarone", University of Torino, Torino, Italy
| | - Emanuela Tolosano
- Deptartment Molecular Biotechnology and Health Sciences and Molecular Biotechnology Center "Guido Tarone", University of Torino, Torino, Italy
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA.
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3
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Balogun O, Nejak-Bowen K. The Hepatic Porphyrias: Revealing the Complexities of a Rare Disease. Semin Liver Dis 2023; 43:446-459. [PMID: 37973028 PMCID: PMC11256094 DOI: 10.1055/s-0043-1776760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The porphyrias are a group of metabolic disorders that are caused by defects in heme biosynthesis pathway enzymes. The result is accumulation of heme precursors, which can cause neurovisceral and/or cutaneous photosensitivity. Liver is commonly either a source or target of excess porphyrins, and porphyria-associated hepatic dysfunction ranges from minor abnormalities to liver failure. In this review, the first of a three-part series, we describe the defects commonly found in each of the eight enzymes involved in heme biosynthesis. We also discuss the pathophysiology of the hepatic porphyrias in detail, covering epidemiology, histopathology, diagnosis, and complications. Cellular consequences of porphyrin accumulation are discussed, with an emphasis on oxidative stress, protein aggregation, hepatocellular cancer, and endothelial dysfunction. Finally, we review current therapies to treat and manage symptoms of hepatic porphyria.
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Affiliation(s)
- Oluwashanu Balogun
- Department of Experimental Pathology, University of Pittsburgh, Pittsburgh, PA
| | - Kari Nejak-Bowen
- Department of Experimental Pathology, University of Pittsburgh, Pittsburgh, PA
- Pittsburgh Liver Institute, University of Pittsburgh, Pittsburgh, PA
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4
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Voltarelli VA, Alves de Souza RW, Miyauchi K, Hauser CJ, Otterbein LE. Heme: The Lord of the Iron Ring. Antioxidants (Basel) 2023; 12:antiox12051074. [PMID: 37237940 DOI: 10.3390/antiox12051074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/26/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023] Open
Abstract
Heme is an iron-protoporphyrin complex with an essential physiologic function for all cells, especially for those in which heme is a key prosthetic group of proteins such as hemoglobin, myoglobin, and cytochromes of the mitochondria. However, it is also known that heme can participate in pro-oxidant and pro-inflammatory responses, leading to cytotoxicity in various tissues and organs such as the kidney, brain, heart, liver, and in immune cells. Indeed, heme, released as a result of tissue damage, can stimulate local and remote inflammatory reactions. These can initiate innate immune responses that, if left uncontrolled, can compound primary injuries and promote organ failure. In contrast, a cadre of heme receptors are arrayed on the plasma membrane that is designed either for heme import into the cell, or for the purpose of activating specific signaling pathways. Thus, free heme can serve either as a deleterious molecule, or one that can traffic and initiate highly specific cellular responses that are teleologically important for survival. Herein, we review heme metabolism and signaling pathways, including heme synthesis, degradation, and scavenging. We will focus on trauma and inflammatory diseases, including traumatic brain injury, trauma-related sepsis, cancer, and cardiovascular diseases where current work suggests that heme may be most important.
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Affiliation(s)
- Vanessa Azevedo Voltarelli
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Rodrigo W Alves de Souza
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Kenji Miyauchi
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Carl J Hauser
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Leo Edmond Otterbein
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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5
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Liu Y, Birsoy K. Metabolic sensing and control in mitochondria. Mol Cell 2023; 83:877-889. [PMID: 36931256 PMCID: PMC10332353 DOI: 10.1016/j.molcel.2023.02.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 03/18/2023]
Abstract
Mitochondria are membrane-enclosed organelles with endosymbiotic origins, harboring independent genomes and a unique biochemical reaction network. To perform their critical functions, mitochondria must maintain a distinct biochemical environment and coordinate with the cytosolic metabolic networks of the host cell. This coordination requires them to sense and control metabolites and respond to metabolic stresses. Indeed, mitochondria adopt feedback or feedforward control strategies to restrain metabolic toxicity, enable metabolic conservation, ensure stable levels of key metabolites, allow metabolic plasticity, and prevent futile cycles. A diverse panel of metabolic sensors mediates these regulatory circuits whose malfunctioning leads to inborn errors of metabolism with mild to severe clinical manifestations. In this review, we discuss the logic and molecular basis of metabolic sensing and control in mitochondria. The past research outlined recurring patterns in mitochondrial metabolic sensing and control and highlighted key knowledge gaps in this organelle that are potentially addressable with emerging technological breakthroughs.
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Affiliation(s)
- Yuyang Liu
- Laboratory of Metabolic Regulation and Genetics, The Rockefeller University, New York, NY, USA
| | - Kıvanç Birsoy
- Laboratory of Metabolic Regulation and Genetics, The Rockefeller University, New York, NY, USA.
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6
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Novakova Z, Milosevic M, Kutil Z, Ondrakova M, Havlinova B, Kasparek P, Sandoval-Acuña C, Korandova Z, Truksa J, Vrbacky M, Rohlena J, Barinka C. Generation and characterization of human U-2 OS cell lines with the CRISPR/Cas9-edited protoporphyrinogen oxidase IX gene. Sci Rep 2022; 12:17081. [PMID: 36224252 PMCID: PMC9556554 DOI: 10.1038/s41598-022-21147-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 09/23/2022] [Indexed: 02/05/2023] Open
Abstract
In humans, disruptions in the heme biosynthetic pathway are associated with various types of porphyrias, including variegate porphyria that results from the decreased activity of protoporphyrinogen oxidase IX (PPO; E.C.1.3.3.4), the enzyme catalyzing the penultimate step of the heme biosynthesis. Here we report the generation and characterization of human cell lines, in which PPO was inactivated using the CRISPR/Cas9 system. The PPO knock-out (PPO-KO) cell lines are viable with the normal proliferation rate and show massive accumulation of protoporphyrinogen IX, the PPO substrate. Observed low heme levels trigger a decrease in the amount of functional heme containing respiratory complexes III and IV and overall reduced oxygen consumption rates. Untargeted proteomics further revealed dysregulation of 22 cellular proteins, including strong upregulation of 5-aminolevulinic acid synthase, the major regulatory protein of the heme biosynthesis, as well as additional ten targets with unknown association to heme metabolism. Importantly, knock-in of PPO into PPO-KO cells rescued their wild-type phenotype, confirming the specificity of our model. Overall, our model system exploiting a non-erythroid human U-2 OS cell line reveals physiological consequences of the PPO ablation at the cellular level and can serve as a tool to study various aspects of dysregulated heme metabolism associated with variegate porphyria.
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Affiliation(s)
- Zora Novakova
- grid.448014.dLaboratory of Structural Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Mirko Milosevic
- grid.448014.dLaboratory of Cellular Metabolism, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic ,grid.4491.80000 0004 1937 116XFaculty of Science, Charles University, Vinicna 5, Prague, 12108 Czech Republic
| | - Zsofia Kutil
- grid.448014.dLaboratory of Structural Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Marketa Ondrakova
- grid.448014.dLaboratory of Structural Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Barbora Havlinova
- grid.448014.dLaboratory of Structural Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Petr Kasparek
- grid.418827.00000 0004 0620 870XCzech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Cristian Sandoval-Acuña
- grid.448014.dLaboratory of Tumour Resistance, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Zuzana Korandova
- grid.418925.30000 0004 0633 9419Laboratory of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, Prague, 14220 Czech Republic ,grid.4491.80000 0004 1937 116XFirst Faculty of Medicine, Charles University, Katerinska 32, Prague, 12108 Czech Republic
| | - Jaroslav Truksa
- grid.448014.dLaboratory of Tumour Resistance, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Marek Vrbacky
- grid.418925.30000 0004 0633 9419Laboratory of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, Prague, 14220 Czech Republic
| | - Jakub Rohlena
- grid.448014.dLaboratory of Cellular Metabolism, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
| | - Cyril Barinka
- grid.448014.dLaboratory of Structural Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, Vestec, 25250 Czech Republic
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7
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Ma CD, Van Horn CG, Wan M, Bishop C, Bonkovsky HL. Assessment of porphyrogenicity of drugs and chemicals in selected hepatic cell culture models through a fluorescence-based screening assay. Pharmacol Res Perspect 2022; 10:e00951. [PMID: 35445802 PMCID: PMC9022196 DOI: 10.1002/prp2.951] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 04/02/2022] [Indexed: 12/15/2022] Open
Abstract
Compounds that induce 5-aminolevulinic acid [ALA] synthase-1 and/or cytochromes P-450 may induce acute porphyric attacks in patients with the acute hepatic porphyrias [AHPs]. Currently, there is no simple, robust model used to assess and predict the porphyrogenicity of drugs and chemicals. Our aim was to develop a fluorescence-based in vitro assay for this purpose. We studied four different hepatic cell culture models: HepG2 cells, LMH cells, 3D HepG2 organoids, and 3D organoids of primary liver cells from people without known disease [normal human controls]. We took advantage of the fluorescent properties of protoporphyrin IX [PP], the last intermediate of the heme biosynthesis pathway, performing fluorescence spectrometry to measure the intensity of fluorescence emitted by these cells treated with selected compounds of importance to patients with AHPs. Among the four cell culture models, the LMH cells produced the highest fluorescence readings, suggesting that these cells retain more robust heme biosynthesis enzymes or that the other cell models may have lost their inducibility of ALA synthase-1 [ALAS-1]. Allyl isopropyl acetamide [AIA], a known potent porphyrogen and inducer of ALAS-1, was used as a positive control to help predict porphyrogenicity for tested compounds. Among the tested compounds (acetaminophen, acetylsalicylic acid, β-estradiol, hydroxychloroquine sulfate, alpha-methyldopa, D (-) norgestrel, phenobarbital, phenytoin, sulfamethoxazole, sulfisoxazole, sodium valproate, and valsartan), concentrations greater than 0.314 mM for norgestrel, phenobarbital, phenytoin, and sodium valproate produced fluorescence readings higher than the reading produced by the positive AIA control. Porphyrin accumulation was also measured by HPLC to confirm the validity of the assay. We conclude that LMH cell cultures in multi-well plates are an inexpensive, robust, and simple system to predict the porphyrogenicity of existing or novel compounds that may exacerbate the AHPs.
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Affiliation(s)
- Christopher D Ma
- Department of Internal Medicine, Section on Gastroenterology and Hepatology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Cynthia G Van Horn
- Department of Internal Medicine, Section on Gastroenterology and Hepatology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Meimei Wan
- Wake Forest Institute for Regenerative Medicine, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Colin Bishop
- Wake Forest Institute for Regenerative Medicine, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Herbert L Bonkovsky
- Department of Internal Medicine, Section on Gastroenterology and Hepatology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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8
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Fleischhacker AS, Sarkar A, Liu L, Ragsdale SW. Regulation of protein function and degradation by heme, heme responsive motifs, and CO. Crit Rev Biochem Mol Biol 2022; 57:16-47. [PMID: 34517731 PMCID: PMC8966953 DOI: 10.1080/10409238.2021.1961674] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Heme is an essential biomolecule and cofactor involved in a myriad of biological processes. In this review, we focus on how heme binding to heme regulatory motifs (HRMs), catalytic sites, and gas signaling molecules as well as how changes in the heme redox state regulate protein structure, function, and degradation. We also relate these heme-dependent changes to the affected metabolic processes. We center our discussion on two HRM-containing proteins: human heme oxygenase-2, a protein that binds and degrades heme (releasing Fe2+ and CO) in its catalytic core and binds Fe3+-heme at HRMs located within an unstructured region of the enzyme, and the transcriptional regulator Rev-erbβ, a protein that binds Fe3+-heme at an HRM and is involved in CO sensing. We will discuss these and other proteins as they relate to cellular heme composition, homeostasis, and trafficking. In addition, we will discuss the HRM-containing family of proteins and how the stability and activity of these proteins are regulated in a dependent manner through the HRMs. Then, after reviewing CO-mediated protein regulation of heme proteins, we turn our attention to the involvement of heme, HRMs, and CO in circadian rhythms. In sum, we stress the importance of understanding the various roles of heme and the distribution of the different heme pools as they relate to the heme redox state, CO, and heme binding affinities.
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Affiliation(s)
- Angela S. Fleischhacker
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anindita Sarkar
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Liu Liu
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Stephen W. Ragsdale
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
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9
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Fiorito V, Allocco AL, Petrillo S, Gazzano E, Torretta S, Marchi S, Destefanis F, Pacelli C, Audrito V, Provero P, Medico E, Chiabrando D, Porporato PE, Cancelliere C, Bardelli A, Trusolino L, Capitanio N, Deaglio S, Altruda F, Pinton P, Cardaci S, Riganti C, Tolosano E. The heme synthesis-export system regulates the tricarboxylic acid cycle flux and oxidative phosphorylation. Cell Rep 2021; 35:109252. [PMID: 34133926 DOI: 10.1016/j.celrep.2021.109252] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 12/21/2020] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
Heme is an iron-containing porphyrin of vital importance for cell energetic metabolism. High rates of heme synthesis are commonly observed in proliferating cells. Moreover, the cell-surface heme exporter feline leukemia virus subgroup C receptor 1a (FLVCR1a) is overexpressed in several tumor types. However, the reasons why heme synthesis and export are enhanced in highly proliferating cells remain unknown. Here, we illustrate a functional axis between heme synthesis and heme export: heme efflux through the plasma membrane sustains heme synthesis, and implementation of the two processes down-modulates the tricarboxylic acid (TCA) cycle flux and oxidative phosphorylation. Conversely, inhibition of heme export reduces heme synthesis and promotes the TCA cycle fueling and flux as well as oxidative phosphorylation. These data indicate that the heme synthesis-export system modulates the TCA cycle and oxidative metabolism and provide a mechanistic basis for the observation that both processes are enhanced in cells with high-energy demand.
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Affiliation(s)
- Veronica Fiorito
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Anna Lucia Allocco
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Sara Petrillo
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Elena Gazzano
- Department of Oncology, University of Torino, Torino, Italy
| | - Simone Torretta
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
| | - Saverio Marchi
- Department of Clinical and Molecular Sciences, Marche Polytechnic University, Ancona, Italy
| | - Francesca Destefanis
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Consiglia Pacelli
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Valentina Audrito
- Immunogenetics Unit, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Paolo Provero
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy; Center for Omics Sciences, San Raffaele Scientific Institute IRCSS, Milano, Italy
| | - Enzo Medico
- Department of Oncology, University of Torino, Candiolo, TO, Italy; Candiolo Cancer Institute, FPO-IRCCS, Candiolo, TO, Italy
| | - Deborah Chiabrando
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Paolo Ettore Porporato
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | | | - Alberto Bardelli
- Department of Oncology, University of Torino, Candiolo, TO, Italy; Candiolo Cancer Institute, FPO-IRCCS, Candiolo, TO, Italy
| | - Livio Trusolino
- Department of Oncology, University of Torino, Candiolo, TO, Italy; Candiolo Cancer Institute, FPO-IRCCS, Candiolo, TO, Italy
| | - Nazzareno Capitanio
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Silvia Deaglio
- Immunogenetics Unit, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Fiorella Altruda
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Paolo Pinton
- Department of Medical Sciences and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Simone Cardaci
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
| | - Chiara Riganti
- Department of Oncology, University of Torino, Torino, Italy
| | - Emanuela Tolosano
- Molecular Biotechnology Center (MBC), Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.
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10
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Swenson SA, Moore CM, Marcero JR, Medlock AE, Reddi AR, Khalimonchuk O. From Synthesis to Utilization: The Ins and Outs of Mitochondrial Heme. Cells 2020; 9:E579. [PMID: 32121449 PMCID: PMC7140478 DOI: 10.3390/cells9030579] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 12/14/2022] Open
Abstract
Heme is a ubiquitous and essential iron containing metallo-organic cofactor required for virtually all aerobic life. Heme synthesis is initiated and completed in mitochondria, followed by certain covalent modifications and/or its delivery to apo-hemoproteins residing throughout the cell. While the biochemical aspects of heme biosynthetic reactions are well understood, the trafficking of newly synthesized heme-a highly reactive and inherently toxic compound-and its subsequent delivery to target proteins remain far from clear. In this review, we summarize current knowledge about heme biosynthesis and trafficking within and outside of the mitochondria.
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Affiliation(s)
| | - Courtney M. Moore
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA;
| | - Jason R. Marcero
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA;
| | - Amy E. Medlock
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA;
- Augusta University/University of Georgia Medical Partnership, Athens, GA 30602, USA
| | - Amit R. Reddi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA;
- Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
- Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
- Fred and Pamela Buffett Cancer Center, Omaha, NE 68105, USA
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11
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Organ-differential responses to ethanol and kynurenic acid, a component of alcoholic beverages in gene transcription. Gene 2020; 737:144434. [PMID: 32018015 DOI: 10.1016/j.gene.2020.144434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 11/24/2022]
Abstract
Excessive alcohol (ethanol) use has long been known to affect human health negatively. However, the underlying molecular basis is incompletely understood. Moreover, consumption of alcohol is often mixed with kynurenic acid (KYNA), an abundant tryptophan metabolite produced during fermentation. The combined effect of ethanol and KYNA on host gene expression has not been investigated. The current study used mice as the model to interrogate the impact of ethanol and/or KYNA on global gene transcription. Adult male mice were administered with 2 g/kg ethanol and/or 0.1 mg/kg KYNA by gavage once a day for a week. Three organs: brain, kidney, and liver were collected and their total RNAs extracted for transcriptome sequencing and quantitative real-time PCR. Gene ontology, Kyoto encyclopedia of genes, and genomes pathway analyses revealed that alcohol affects the three organs differentially. Furthermore, the gene expression profile from alcohol and KYNA co-administration was significantly different from that of alcohol or KYNA administration alone. Strikingly, Indolamine 2,3-dioxygenase 1, a rate-limiting enzyme in tryptophan metabolism, was significantly increased in the brain after a combined exposure of alcohol and KYNA, suggesting that Trp metabolism was skewed towards the kynurenine pathway in the brain. Our systemic analysis provides new insights into the mechanism whereby alcohol and KYNA affects organ functions.
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Biliverdin reductase deficiency triggers an endothelial-to-mesenchymal transition in human endothelial cells. Arch Biochem Biophys 2019; 678:108182. [DOI: 10.1016/j.abb.2019.108182] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 10/05/2019] [Accepted: 11/04/2019] [Indexed: 02/07/2023]
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Ifhar LS, Ene HM, Ben-Shachar D. Impaired heme metabolism in schizophrenia-derived cell lines and in a rat model of the disorder: Possible involvement of mitochondrial complex I. Eur Neuropsychopharmacol 2019; 29:577-589. [PMID: 30948194 DOI: 10.1016/j.euroneuro.2019.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 03/18/2019] [Accepted: 03/22/2019] [Indexed: 02/07/2023]
Abstract
Accumulating data point to heme involvement in neuropsychiatric disorders. Heme plays a role in major cellular processes such as signal transduction, protein complex assembly and regulation of transcription and translation. Its synthesis involves the mitochondria, which dysfunction, specifically that of the complex I (Co-I) of the electron transport chain is involved in the pathophysiology of schizophrenia (SZ). Here we aimed to demonstrate that deficits in Co-I affect heme metabolism. We show a significant decrease in heme levels in Co-I deficient SZ-derived EBV transformed lymphocytes (lymphoblastoid cell lines - LCLs) as compared to healthy subjects-derived cells (n = 9/cohort). Moreover, protein levels assessed by immunoblotting and mRNA levels assessed by qRT-PCR of heme catabolic enzyme, heme Oxygenase 1 (HO-1), and protein levels of heme downstream target phosphorylated eukaryotic initiation factor 2-alpha (Peif2a/eif2a) were significantly elevated in SZ-derived cells. In contrast, protein and mRNA levels of heme synthesis rate limiting enzyme aminolevulinic acid synthase-1 (ALAS1) were unchanged in SZ derived LCLs. In addition, inhibition of Co-I by rotenone in healthy subjects-derived LCLs (n = 4/cohort) exhibited an initial increase followed by a later decrease in heme levels. These findings were associated with opposite changes in heme's downstream target and HO-1 level, similar to our findings in SZ-derived cells. We also show a brain region specific pattern of impairment in Co-I subunits and in HO-1 and PeIF2α/eIF2α in the Poly-IC rat model of SZ (n = 6/cohort). Our results provide evidence for a link between CoI and heme metabolism both in-vitro and in-vivo suggesting its contribution to SZ pathophysiology.
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Affiliation(s)
- Lee S Ifhar
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine, Rappaport Family Institute for Research in Medical Sciences, Technion IIT, POB 9649, Haifa 31096 Israel
| | - Hila M Ene
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine, Rappaport Family Institute for Research in Medical Sciences, Technion IIT, POB 9649, Haifa 31096 Israel
| | - Dorit Ben-Shachar
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine, Rappaport Family Institute for Research in Medical Sciences, Technion IIT, POB 9649, Haifa 31096 Israel.
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Activated glycine receptors may decrease endosomal NADPH oxidase activity by opposing ClC-3-mediated efflux of chloride from endosomes. Med Hypotheses 2019; 123:125-129. [DOI: 10.1016/j.mehy.2019.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/15/2019] [Indexed: 12/25/2022]
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15
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Ikushiro H, Nagami A, Takai T, Sawai T, Shimeno Y, Hori H, Miyahara I, Kamiya N, Yano T. Heme-dependent Inactivation of 5-Aminolevulinate Synthase from Caulobacter crescentus. Sci Rep 2018; 8:14228. [PMID: 30242198 PMCID: PMC6154995 DOI: 10.1038/s41598-018-32591-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 09/11/2018] [Indexed: 11/09/2022] Open
Abstract
The biosynthesis of heme is strictly regulated, probably because of the toxic effects of excess heme and its biosynthetic precursors. In many organisms, heme biosynthesis starts with the production of 5-aminolevulinic acid (ALA) from glycine and succinyl-coenzyme A, a process catalyzed by a homodimeric enzyme, pyridoxal 5′-phosphate (PLP)-dependent 5-aminolevulinate synthase (ALAS). ALAS activity is negatively regulated by heme in various ways, such as the repression of ALAS gene expression, degradation of ALAS mRNA, and inhibition of mitochondrial translocation of the mammalian precursor protein. There has been no clear evidence, however, that heme directly binds to ALAS to negatively regulate its activity. We found that recombinant ALAS from Caulobacter crescentus was inactivated via a heme-mediated feedback manner, in which the essential coenzyme PLP was rel eased to form the inactive heme-bound enzyme. The spectroscopic properties of the heme-bound ALAS showed that a histidine-thiolate hexa-coordinated ferric heme bound to each subunit with a one-to-one stoichiometry. His340 and Cys398 were identified as the axial ligands of heme, and mutant ALASs lacking either of these ligands became resistant to heme-mediated inhibition. ALAS expressed in C. crescentus was also found to bind heme, suggesting that heme-mediated feedback inhibition of ALAS is physiologically relevant in C. crescentus.
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Affiliation(s)
- Hiroko Ikushiro
- Department of Biochemistry, Faculty of Medicine, Osaka Medical College, Osaka, 569-8686, Japan.
| | - Atsushi Nagami
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Tomoko Takai
- Department of Biochemistry, Faculty of Medicine, Osaka Medical College, Osaka, 569-8686, Japan.,Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Taiki Sawai
- Department of Biochemistry, Faculty of Medicine, Osaka Medical College, Osaka, 569-8686, Japan
| | - Yuki Shimeno
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Hiroshi Hori
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Ikuko Miyahara
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Nobuo Kamiya
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan.,The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Osaka, 558-8585, Japan
| | - Takato Yano
- Department of Biochemistry, Faculty of Medicine, Osaka Medical College, Osaka, 569-8686, Japan.
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Fruttero LL, Moyetta NR, Krug MS, Broll V, Grahl MVC, Real-Guerra R, Stanisçuaski F, Carlini CR. Jaburetox affects gene expression and enzyme activities in Rhodnius prolixus, a Chagas' disease vector. Acta Trop 2017; 168:54-63. [PMID: 28108369 DOI: 10.1016/j.actatropica.2017.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/09/2017] [Accepted: 01/12/2017] [Indexed: 12/18/2022]
Abstract
Jaburetox, a recombinant peptide of ∼11kDa derived from one of the Canavalia ensiformis (Jack Bean) urease isoforms, is toxic and lethal to insects belonging to different orders when administered orally or via injection. Previous findings indicated that Jaburetox acts on insects in a complex fashion, inhibiting diuresis and the transmembrane potential of Malpighian tubules, interfering with muscle contractility and affecting the immune system. In vitro, Jaburetox forms ionic channels and alters permeability of artificial lipid membranes. Moreover, recent data suggested that the central nervous system (CNS) is a target organ for ureases and Jaburetox. In this work, we employed biochemical, molecular and cellular approaches to explore the mode of action of Jaburetox using Rhodnius prolixus, one of the main Chagas' disease vectors, as experimental model. In vitro incubations with fluorescently labeled Jaburetox indicated a high affinity of the peptide for the CNS but not for salivary glands (SG). The in vitro treatment of CNS or SG homogenates with Jaburetox partially inhibited the activity of nitric oxide synthase (NOS), thus disrupting nitrinergic signaling. This inhibitory effect was also observed in vivo (by feeding) for CNS but not for SG, implying differential modulation of NOS in these organs. The inhibition of NOS activity did not correlate to a decrease in expression of its mRNA, as assessed by qPCR. UDP-N-acetylglucosamine pyrophosphorylase (UAP), a key enzyme in chitin synthesis and glycosylation pathways and a known target of Jaburetox in insect CNS, was also affected in SG, with activation of the enzyme seen after both in vivo or in vitro treatments with the peptide. Unexpectedly, incubation of Jaburetox with a recombinant R. prolixus UAP had no effect on its activity, implying that the enzyme's modulation by the peptide requires the participation of other factor(s) present in CNS or SG homogenates. Feeding Jaburetox to R. prolixus decreased the mRNA levels of UAP and chitin synthase, indicating a complex regulation exerted by the peptide on these enzymes. No changes were observed upon Jaburetox treatment in vivo and in vitro on the activity of the enzyme acid phosphatase, a possible link between UAP and NOS. Here we have demonstrated for the first time that the Jaburetox induces changes in gene expression and that SG are another target for the toxic action of the peptide. Taken together, these findings contribute to a better understanding of the mechanism of action of Jaburetox as well as to the knowledge on basic aspects of the biochemistry and neurophysiology of insects, and might help in the development of optimized strategies for insect control.
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Affiliation(s)
- Leonardo L Fruttero
- Brain Institute (Instituto do Cérebro-INSCER), Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6690, prédio 63, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil; Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, prédio 43431, CEP 91501-970, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Natalia R Moyetta
- Brain Institute (Instituto do Cérebro-INSCER), Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6690, prédio 63, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Monique Siebra Krug
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, prédio 43431, CEP 91501-970, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Valquiria Broll
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, prédio 43431, CEP 91501-970, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Matheus V Coste Grahl
- Brain Institute (Instituto do Cérebro-INSCER), Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6690, prédio 63, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Rafael Real-Guerra
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, prédio 43431, CEP 91501-970, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Fernanda Stanisçuaski
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, prédio 43431, CEP 91501-970, Porto Alegre, Rio Grande do Sul, Brazil; Department of Molecular Biology and Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, prédio 43431, CEP 91501-970, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Celia R Carlini
- Brain Institute (Instituto do Cérebro-INSCER), Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6690, prédio 63, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil; Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, prédio 43431, CEP 91501-970, Porto Alegre, Rio Grande do Sul, Brazil.
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Abstract
INTRODUCTION Mitochondria are cellular organelles that perform numerous bioenergetic, biosynthetic, and regulatory functions and play a central role in iron metabolism. Extracellular iron is taken up by cells and transported to the mitochondria, where it is utilized for synthesis of cofactors essential to the function of enzymes involved in oxidation-reduction reactions, DNA synthesis and repair, and a variety of other cellular processes. Areas covered: This article reviews the trafficking of iron to the mitochondria and normal mitochondrial iron metabolism, including heme synthesis and iron-sulfur cluster biogenesis. Much of our understanding of mitochondrial iron metabolism has been revealed by pathologies that disrupt normal iron metabolism. These conditions affect not only iron metabolism but mitochondrial function and systemic health. Therefore, this article also discusses these pathologies, including conditions of systemic and mitochondrial iron dysregulation as well as cancer. Literature covering these areas was identified via PubMed searches using keywords: Iron, mitochondria, Heme Synthesis, Iron-sulfur Cluster, and Cancer. References cited by publications retrieved using this search strategy were also consulted. Expert commentary: While much has been learned about mitochondrial and its iron, key questions remain. Developing a better understanding of mitochondrial iron and its regulation will be paramount in developing therapies for syndromes that affect mitochondrial iron.
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Affiliation(s)
- Bibbin T. Paul
- Department of Molecular Biology and Biophysics, University of Connecticut Health, Farmington, Connecticut
| | - David H. Manz
- Department of Molecular Biology and Biophysics, University of Connecticut Health, Farmington, Connecticut
- School of Dental Medicine, University of Connecticut Health, Farmington, Connecticut
| | - Frank M. Torti
- Department of Medicine, University of Connecticut Health, Farmington, Connecticut
| | - Suzy V. Torti
- Department of Molecular Biology and Biophysics, University of Connecticut Health, Farmington, Connecticut
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Barupala DP, Dzul SP, Riggs-Gelasco PJ, Stemmler TL. Synthesis, delivery and regulation of eukaryotic heme and Fe-S cluster cofactors. Arch Biochem Biophys 2016; 592:60-75. [PMID: 26785297 PMCID: PMC4784227 DOI: 10.1016/j.abb.2016.01.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 01/13/2016] [Accepted: 01/14/2016] [Indexed: 11/25/2022]
Abstract
In humans, the bulk of iron in the body (over 75%) is directed towards heme- or Fe-S cluster cofactor synthesis, and the complex, highly regulated pathways in place to accomplish biosynthesis have evolved to safely assemble and load these cofactors into apoprotein partners. In eukaryotes, heme biosynthesis is both initiated and finalized within the mitochondria, while cellular Fe-S cluster assembly is controlled by correlated pathways both within the mitochondria and within the cytosol. Iron plays a vital role in a wide array of metabolic processes and defects in iron cofactor assembly leads to human diseases. This review describes progress towards our molecular-level understanding of cellular heme and Fe-S cluster biosynthesis, focusing on the regulation and mechanistic details that are essential for understanding human disorders related to the breakdown in these essential pathways.
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Affiliation(s)
- Dulmini P Barupala
- Departments of Biochemistry and Molecular Biology, and Pharmaceutical Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Stephen P Dzul
- Departments of Biochemistry and Molecular Biology, and Pharmaceutical Sciences, Wayne State University, Detroit, MI 48201, USA
| | | | - Timothy L Stemmler
- Departments of Biochemistry and Molecular Biology, and Pharmaceutical Sciences, Wayne State University, Detroit, MI 48201, USA.
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20
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Chiabrando D, Vinchi F, Fiorito V, Mercurio S, Tolosano E. Heme in pathophysiology: a matter of scavenging, metabolism and trafficking across cell membranes. Front Pharmacol 2014; 5:61. [PMID: 24782769 PMCID: PMC3986552 DOI: 10.3389/fphar.2014.00061] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/18/2014] [Indexed: 01/19/2023] Open
Abstract
Heme (iron-protoporphyrin IX) is an essential co-factor involved in multiple biological processes: oxygen transport and storage, electron transfer, drug and steroid metabolism, signal transduction, and micro RNA processing. However, excess free-heme is highly toxic due to its ability to promote oxidative stress and lipid peroxidation, thus leading to membrane injury and, ultimately, apoptosis. Thus, heme metabolism needs to be finely regulated. Intracellular heme amount is controlled at multiple levels: synthesis, utilization by hemoproteins, degradation and both intracellular and intercellular trafficking. This review focuses on recent findings highlighting the importance of controlling intracellular heme levels to counteract heme-induced oxidative stress. The contributions of heme scavenging from the extracellular environment, heme synthesis and incorporation into hemoproteins, heme catabolism and heme transport in maintaining adequate intracellular heme content are discussed. Particular attention is put on the recently described mechanisms of heme trafficking through the plasma membrane mediated by specific heme importers and exporters. Finally, the involvement of genes orchestrating heme metabolism in several pathological conditions is illustrated and new therapeutic approaches aimed at controlling heme metabolism are discussed.
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Affiliation(s)
- Deborah Chiabrando
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Francesca Vinchi
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Veronica Fiorito
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Sonia Mercurio
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Emanuela Tolosano
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
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21
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Larion S, Caballes FR, Hwang SI, Lee JG, Rossman WE, Parsons J, Steuerwald N, Li T, Maddukuri V, Groseclose G, Finkielstein CV, Bonkovsky HL. Circadian rhythms in acute intermittent porphyria--a pilot study. Eur J Clin Invest 2013; 43:727-39. [PMID: 23650938 PMCID: PMC3687345 DOI: 10.1111/eci.12102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 04/01/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Acute intermittent porphyria (AIP) is an inherited disorder of haem synthesis wherein a partial deficiency of porphobilinogen (PBG) deaminase (PBGD) with other factors may give rise to biochemical and clinical manifestations of disease. The biochemical hallmarks of active AIP are relative hepatic haem deficiency and uncontrolled up-regulation of hepatic 5-aminolevulinic acid (ALA) synthase-1 (ALAS1) with over-production of ALA and PBG. The treatment of choice is intravenous haem, which restores the deficient regulatory haem pool of the liver and represses ALAS1. Recently, haem has been shown to influence circadian rhythms by controlling their negative feedback loops. We evaluated whether subjects with AIP exhibited an altered circadian profile. MATERIALS AND METHODS Over a 21-h period, we measured levels of serum cortisol, melatonin, ALA, PBG and mRNA levels (in peripheral blood mononuclear cells) of selected clock-controlled genes and genes involved in haem synthesis in 10 Caucasian (European-American) women who were either postmenopausal or had been receiving female hormone therapy, six of whom have AIP and four do not and are considered controls. RESULTS Four AIP subjects with biochemical activity exhibited higher levels of PBG and lower levels and dampened oscillation of serum cortisol, and a trend for lower levels of serum melatonin, than controls or AIP subjects without biochemical activity. Levels of clock-controlled gene mRNAs showed significant increases over baseline in all subjects at 5 a.m. and 11 p.m., whereas mRNA levels of ALAS1, ALAS2 and PBGD were increased only at 11 p.m. in subjects with active AIP. CONCLUSIONS This pilot study provides evidence for disturbances of circadian markers in women with active AIP that may trigger or sustain some common clinical features of AIP.
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Affiliation(s)
- Sebastian Larion
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
| | - F. Ryan Caballes
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Medicine, Carolinas Medical Center, Charlotte, NC
| | - Sun-Il Hwang
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Research, Carolinas Medical Center, Charlotte, NC
| | - Jin-Gyun Lee
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Research, Carolinas Medical Center, Charlotte, NC
| | - Whitney Ellefson Rossman
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Research, Carolinas Medical Center, Charlotte, NC
| | - Judy Parsons
- Department of Research, Carolinas Medical Center, Charlotte, NC
| | - Nury Steuerwald
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Research, Carolinas Medical Center, Charlotte, NC
| | - Ting Li
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Research, Carolinas Medical Center, Charlotte, NC
| | - Vinaya Maddukuri
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Medicine, Carolinas Medical Center, Charlotte, NC
| | - Gale Groseclose
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Research, Carolinas Medical Center, Charlotte, NC
| | - Carla V. Finkielstein
- The Integrated Cellular Responses Laboratory, Department of Biological Sciences, Virginia Tech, Blacksburg, VA
| | - Herbert L. Bonkovsky
- The Liver-Biliary-Pancreatic Center, Carolinas Medical Center, Charlotte, NC
- Department of Research, Carolinas Medical Center, Charlotte, NC
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Quintanilla-Vega B, Hernandez A, Mendoza-Figueroa T. Reduction in porphyrin excretion as a sensitive indicator of lead toxicity in primary cultures of adult rat hepatocytes. Toxicol In Vitro 2012; 10:675-83. [PMID: 20650251 DOI: 10.1016/s0887-2333(96)00043-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/1996] [Indexed: 11/16/2022]
Abstract
Alterations of specific metabolic pathways can be used as sensitive indicators of toxicity by chemicals and can give valuable information on the mechanism(s) involved. Short-term effects of lead on hepatic haem biosynthesis were studied in an in vitro system. Primary cultures of adult rat hepatocytes were exposed for 24-48 hr to lead (0.024-3.6 mm), and excreted and intracellular porphyrins were measured in untreated and lead-treated cultures. Cytotoxicity, as estimated by enzyme leakage, and morphological alterations were also evaluated. Control hepatocytes produced porphyrins at a rate of 387 pmol/mg cellular protein/day. Most of the released and intracellular porphyrins were protoporphyrins, although uro- and coproporphyrins were also detected in lower amounts. After 24 hr of exposure to 0.1-3.6 mm Pb(2+) , excreted porphyrins decreased by 24-92% and intracellular porphyrins by 36-60%, while 48 hr of exposure to 0.024-3.6 mm Pb(2+) caused a progressive reduction of 77-97% in porphyrin excretion and of 49-67% in intracellular porphyrins. Lead exposure also produced a differential decrease of proto-, copro- and uro-porphyrin excretion. These lead effects can be explained mainly by inhibition of the enzyme 5-aminolaevulinate dehydratase, resulting in a decreased monopyrrole supply for porphyrin biosynthesis, and probably by inhibition of the enzyme uroporphyrinogen decarboxylase. Morphological alterations and enzyme leakage were detected only after 24 hr of exposure to 2.4 mm and 48 hr of exposure to 3.6 mm Pb(2+), respectively. The results show that changes in porphyrin production, and particularly in their excretion, in cultured rat hepatocytes are useful indicators of lead toxicity, since they are more sensitive than enzyme leakage and can give preliminary information on the enzyme(s) that could be affected. They also suggest the potential benefits of the use of this method for the evaluation of compounds that alter haem biosynthesis.
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Affiliation(s)
- B Quintanilla-Vega
- Sección de Toxicología Ambiental, Centro de Investigatión y de Estudios Avanzados del IPN, Ap. Postal 14-740, México, D.F., 07000, México
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Larsen R, Gouveia Z, Soares MP, Gozzelino R. Heme cytotoxicity and the pathogenesis of immune-mediated inflammatory diseases. Front Pharmacol 2012; 3:77. [PMID: 22586395 PMCID: PMC3343703 DOI: 10.3389/fphar.2012.00077] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 04/11/2012] [Indexed: 01/01/2023] Open
Abstract
Heme, iron (Fe) protoporphyrin IX, functions as a prosthetic group in a range of hemoproteins essential to support life under aerobic conditions. The Fe contained within the prosthetic heme groups of these hemoproteins can catalyze the production of reactive oxygen species. Presumably for this reason, heme must be sequestered within those hemoproteins, thereby shielding the reactivity of its Fe-heme. However, under pathologic conditions associated with oxidative stress, some hemoproteins can release their prosthetic heme groups. While this heme is not necessarily damaging per se, it becomes highly cytotoxic in the presence of a range of inflammatory mediators such as tumor necrosis factor. This can lead to tissue damage and, as such, exacerbate the pathologic outcome of several immune-mediated inflammatory conditions. Presumably, targeting “free heme” may be used as a therapeutic intervention against these diseases.
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Alves LR, Costa ES, Sorgine MHF, Nascimento-Silva MCL, Teodosio C, Bárcena P, Castro-Faria-Neto HC, Bozza PT, Orfao A, Oliveira PL, Maya-Monteiro CM. Heme-oxygenases during erythropoiesis in K562 and human bone marrow cells. PLoS One 2011; 6:e21358. [PMID: 21765894 PMCID: PMC3135583 DOI: 10.1371/journal.pone.0021358] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 05/30/2011] [Indexed: 01/20/2023] Open
Abstract
In mammalian cells, heme can be degraded by heme-oxygenases (HO). Heme-oxygenase 1 (HO-1) is known to be the heme inducible isoform, whereas heme-oxygenase 2 (HO-2) is the constitutive enzyme. Here we investigated the presence of HO during erythroid differentiation in human bone marrow erythroid precursors and K562 cells. HO-1 mRNA and protein expression levels were below limits of detection in K562 cells. Moreover, heme was unable to induce HO-1, at the protein and mRNA profiles. Surprisingly, HO-2 expression was inhibited upon incubation with heme. To evaluate the physiological relevance of these findings, we analyzed HO expression during normal erythropoiesis in human bone marrow. Erythroid precursors were characterized by lack of significant expression of HO-1 and by progressive reduction of HO-2 during differentiation. FLVCR expression, a recently described heme exporter found in erythroid precursors, was also analyzed. Interestingly, the disruption in the HO detoxification system was accompanied by a transient induction of FLVCR. It will be interesting to verify if the inhibition of HO expression, that we found, is preventing a futile cycle of concomitant heme synthesis and catabolism. We believe that a significant feature of erythropoiesis could be the replacement of heme breakdown by heme exportation, as a mechanism to prevent heme toxicity.
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Affiliation(s)
- Liliane R. Alves
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elaine S. Costa
- Instituto de Pediatria e Puericultura Martagão Gesteira, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcos H. F. Sorgine
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Cristina Teodosio
- Centro de Investigación del Cáncer, Departamento de Medicina and Servicio de Citometria, Universidad de Salamanca, Salamanca, Spain
| | - Paloma Bárcena
- Centro de Investigación del Cáncer, Departamento de Medicina and Servicio de Citometria, Universidad de Salamanca, Salamanca, Spain
| | - Hugo C. Castro-Faria-Neto
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Patrícia T. Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Alberto Orfao
- Centro de Investigación del Cáncer, Departamento de Medicina and Servicio de Citometria, Universidad de Salamanca, Salamanca, Spain
| | - Pedro L. Oliveira
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil
- * E-mail: (CMMM); (PLO)
| | - Clarissa M. Maya-Monteiro
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- * E-mail: (CMMM); (PLO)
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Tian Q, Li T, Hou W, Zheng J, Schrum LW, Bonkovsky HL. Lon peptidase 1 (LONP1)-dependent breakdown of mitochondrial 5-aminolevulinic acid synthase protein by heme in human liver cells. J Biol Chem 2011; 286:26424-30. [PMID: 21659532 DOI: 10.1074/jbc.m110.215772] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
5-Aminolevulinic acid synthase (ALAS-1) is the first rate controlling enzyme that controls cellular heme biosynthesis. Negative feedback regulation of ALAS-1 by the end product heme is well documented and provides the foundation for heme treatment of acute porphyrias, a group of diseases caused by genetic defects in the heme biosynthesis pathway and exacerbated by controlled up-regulation of ALAS-1. Heme is known to affect ALAS-1 activity by repressing gene transcription, accelerating mRNA degradation, and impeding pre-ALAS-1 mitochondrial translocation. In the current study, we examined the effect of heme on the rate of mature ALAS-1 protein turnover in human cells and tissues and explored the mediator involved in this new regulatory mechanism. We found that heme and other metalloporphyrins such as CoPP and CrPP decreased mitochondrial ALAS-1 protein through proteolysis. This degradative effect cannot be emulated by iron or free protoporphyrin, two major chemical components of the heme ring, and is independent of oxidative stress. Down-regulating the activity of mitochondrial LONP1, an ATP-dependent protease that controls the selective turnover of mitochondrial matrix proteins, with potent inhibitors and specific siRNA diminished the negative effect of heme on mitochondrial ALAS-1. Therefore, our data support the existence of a conserved heme feedback regulatory mechanism that functions on the mature form of ALAS-1 protein through the activity of a mitochondrial proteolytic system.
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Affiliation(s)
- Qing Tian
- Liver, Digestive, and Metabolic Disorders Laboratory, Carolinas Medical Center, Charlotte, North Carolina 28203, USA
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26
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Correia MA, Sinclair PR, De Matteis F. Cytochrome P450 regulation: the interplay between its heme and apoprotein moieties in synthesis, assembly, repair, and disposal. Drug Metab Rev 2010; 43:1-26. [PMID: 20860521 DOI: 10.3109/03602532.2010.515222] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Heme is vital to our aerobic universe. Heme cellular content is finely tuned through an exquisite control of synthesis and degradation. Heme deficiency is deleterious to cells, whereas excess heme is toxic. Most of the cellular heme serves as the prosthetic moiety of functionally diverse hemoproteins, including cytochromes P450 (P450s). In the liver, P450s are its major consumers, with >50% of hepatic heme committed to their synthesis. Prosthetic heme is the sine qua non of P450 catalytic biotransformation of both endo- and xenobiotics. This well-recognized functional role notwithstanding, heme also regulates P450 protein synthesis, assembly, repair, and disposal. These less well-appreciated aspects are reviewed herein.
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Affiliation(s)
- Maria Almira Correia
- Department of Cellular and Molecular Pharmacology, The Liver Center, University of California, San Francisco, 94158, USA.
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27
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Abstract
Heme oxygenases (HO) catabolize free heme, that is, iron (Fe) protoporphyrin (IX), into equimolar amounts of Fe(2+), carbon monoxide (CO), and biliverdin. The stress-responsive HO-1 isoenzyme affords protection against programmed cell death. The mechanism underlying this cytoprotective effect relies on the ability of HO-1 to catabolize free heme and prevent it from sensitizing cells to undergo programmed cell death. This cytoprotective effect inhibits the pathogenesis of a variety of immune-mediated inflammatory diseases.
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Okano S, Zhou L, Kusaka T, Shibata K, Shimizu K, Gao X, Kikuchi Y, Togashi Y, Hosoya T, Takahashi S, Nakajima O, Yamamoto M. Indispensable function for embryogenesis, expression and regulation of the nonspecific form of the 5-aminolevulinate synthase gene in mouse. Genes Cells 2009; 15:77-89. [PMID: 20015225 DOI: 10.1111/j.1365-2443.2009.01366.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The first step of heme biosynthesis in animals is catalyzed by 5-aminolevulinate synthase (ALAS), which controls heme supply in various tissues. To clarify the roles that the nonspecific isoform of ALAS (ALAS-N) plays in vivo, we prepared a green fluorescent protein (GFP) knock-in mouse line in which the Alas1 gene (encoding ALAS-N) is replaced with a gfp gene. We found that mice bearing a homozygous knock-in allele (Alas1(GFP/GFP)) were lethal by embryonic day 8.5, demonstrating that ALAS-N is essential for early embryogenesis. Fluorescence microscopic and flow cytometric analyses of heterozygous mouse (Alas1(+/GFP)) tissues showed that the Alas1 expression level differs substantially in tissues; Alas1 is highly expressed in testis Leydig cells, exocrine glands (including submandibular and parotid glands), endocrine glands (such as adrenal and thyroid glands) and hematopoietic lineage cells (including neutrophils and eosinophils). Quantitative analyses of GFP mRNA and ALAS-N mRNA in various tissues of Alas1(+/GFP) mice suggested that the destabilization of ALAS-N mRNA was not uniform in the various tissues. These results thus lay bare that elaborate control of the endogenous heme supply operates in various mouse tissues through regulation of the ALAS-N expression level and that this control is essential for heme homeostasis in animals.
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Affiliation(s)
- Satoshi Okano
- Research Laboratory for Molecular Genetics, Yamagata University, Yamagata 990-9585, Japan
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Sheftel AD, Lill R. The power plant of the cell is also a smithy: the emerging role of mitochondria in cellular iron homeostasis. Ann Med 2009; 41:82-99. [PMID: 18720092 DOI: 10.1080/07853890802322229] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Iron is required for a barrage of essential biochemical functions in virtually every species of life. Perturbation of the availability or utilization of iron in these functions or disruption of other components along iron-requiring pathways can not only lead to cellular/organismal insufficiency of respective biochemical end-products but also result in a broad derangement of iron homeostasis. This is largely because of the elaborate regulatory mechanisms that connect cellular iron utilization with uptake and distribution. Such mechanisms are necessitated by the 'double-edged' nature of the metal, whose very property as a useful biological catalyst also makes it able to generate highly toxic compounds. Since the majority of iron is dispatched onto a functional course by mitochondria-localized pathways, these organelles are in an ideal position within the cellular iron anabolic pathways to be a central site for regulation of iron homeostasis. The goal of this article is to provide an overview of how mitochondria acquire and use iron and examine the ramifications of disturbances in these processes on overall cellular iron homeostasis.
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Affiliation(s)
- Alex D Sheftel
- Institut fur Zytobiologie, Philipps Universitat Marburg, Germany
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30
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Niittynen M, Tuomisto JT, Pohjanvirta R. Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on heme oxygenase-1, biliverdin IXα reductase and δ-aminolevulinic acid synthetase 1 in rats with wild-type or variant AH receptor. Toxicology 2008; 250:132-42. [DOI: 10.1016/j.tox.2008.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 06/26/2008] [Accepted: 06/30/2008] [Indexed: 10/21/2022]
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31
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Zheng J, Shan Y, Lambrecht RW, Donohue SE, Bonkovsky HL. Differential regulation of human ALAS1 mRNA and protein levels by heme and cobalt protoporphyrin. Mol Cell Biochem 2008; 319:153-61. [PMID: 18719978 DOI: 10.1007/s11010-008-9888-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2008] [Accepted: 07/23/2008] [Indexed: 10/21/2022]
Abstract
5-Aminolevulinic acid synthase 1 (ALAS1) is the first and rate-controlling enzyme of heme biosynthesis. This study was to determine the effects of heme and selected nonheme metalloporphyrins on human ALAS1 gene expression in hepatocytes. We found that, upon heme and cobalt protoporphyrin (CoPP) treatments, ALAS1 mRNA levels were down-regulated significantly by ca. 50% or more. Measurement of mRNA in the presence of actinomycin D showed that these down-regulations were due to the decreases in mRNA half-lives. Furthermore, the levels of mitochondrial mature ALAS1 protein were down-regulated by 60-70%, but those of the cytosolic precursor protein were up-regulated by 2-5-fold. Measurement of protein in the presence of cycloheximide (CHX) suggests that elevation of the precursor form is due to the increase in protein half-lives. These results provide novel insights into the mechanisms of heme repressional effects on ALAS1 and provide a rationale for further investigation of CoPP as a therapeutic agent for acute porphyric syndromes.
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Affiliation(s)
- Jianyu Zheng
- Carolinas Medical Center, Charlotte, NC 28203, USA
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Abstract
The constitutive isoform of heme oxygenase, HO-2, is highly expressed in the brain and in cerebral vessels. HO-2 functions in the brain have been evaluated using pharmacological inhibitors of the enzyme and HO-2 gene deletion in in vivo animal models and in cultured cells (neurons, astrocytes, cerebral vascular endothelial cells). Rapid activation of HO-2 via post-translational modifications without upregulation of HO-2 expression or HO-1 induction coincides with the increase in cerebral blood flow aimed at maintaining brain homeostasis and neuronal survival during seizures, hypoxia, and hypotension. Pharmacological inhibition or gene deletion of brain HO-2 exacerbates oxidative stress induced by seizures, glutamate, and inflammatory cytokines, and causes cerebral vascular injury. Carbon monoxide (CO) and bilirubin, the end products of HO-catalyzed heme degradation, have distinct cytoprotective functions. CO, by binding to a heme prosthetic group, regulates the key components of cell signaling, including BK(Ca) channels, guanylyl cyclase, NADPH oxidase, and the mitochondria respiratory chain. Cerebral vasodilator effects of CO are mediated via activation of BK(Ca) channels and guanylyl cyclase. CO, by inhibiting the major components of endogenous oxidant-generating machinery, NADPH oxidase and the cytochrome C oxidase of the mitochondrial respiratory chain, blocks formation of reactive oxygen species. Bilirubin, via redox cycling with biliverdin, is a potent oxidant scavenger that removes preformed oxidants. Overall, HO-2 has dual housekeeping cerebroprotective functions by maintaining autoregulation of cerebral blood flow aimed at improving neuronal survival in a changing environment, and by providing an effective defense mechanism that blocks oxidant formation and prevents cell death caused by oxidative stress.
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Affiliation(s)
- Helena Parfenova
- Laboratory for Research in Neonatal Physiology, Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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Furuyama K, Kaneko K, Vargas PD. Heme as a magnificent molecule with multiple missions: heme determines its own fate and governs cellular homeostasis. TOHOKU J EXP MED 2007; 213:1-16. [PMID: 17785948 DOI: 10.1620/tjem.213.1] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Heme is a prosthetic group of various types of proteins, such as hemoglobin, myoglobin, cytochrome c, cytochrome p450, catalase and peroxidase. In addition, heme is involved in a variety of biological events by modulating the function or the state of hemoproteins. For example, protein synthesis is inhibited in erythroid cells under heme deficiency, as the consequence of the activation of heme-regulated inhibitor (HRI). Iron concentration in the cell is sensed and regulated by the heme-mediated oxidization and subsequent degradation of iron regulatory protein 2 (IRP2). Heme also binds to certain types of potassium channels, thereby inhibiting transmembrane K(+) currents. Importantly, heme determines its own fate; namely, heme regulates its synthesis and degradation through the feedback mechanisms, by which intracellular heme level is precisely maintained. Heme reduces heme synthesis by suppressing the expression of non-specific 5-aminolevulinate synthase (ALAS1) and stimulates heme breakdown by inducing heme oxygenase (HO)-1 expression. ALAS1 and HO-1 are the rate limiting enzymes in heme biosynthesis and catabolism, respectively. Accordingly, under the heme-rich condition, heme binds to cysteine-proline (CP) motifs of ALAS1 and those of transcriptional repressor Bach1, thereby leading to repression of mitochondrial transport of ALAS1 and induction of HO-1 transcription, respectively. Moreover, chemosensing functions of HO-2 containing CP motifs, another isozyme of HO, have been unveiled recently. In this review article, we summarize and update the pleiotropic effects of heme on various biological events and the regulatory network of heme biosynthesis and catabolism.
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Affiliation(s)
- Kazumichi Furuyama
- Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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Shinjyo N, Kita K. Up-Regulation of Heme Biosynthesis during Differentiation of Neuro2a Cells. ACTA ACUST UNITED AC 2006; 139:373-81. [PMID: 16567402 DOI: 10.1093/jb/mvj040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Heme is an iron-containing tetrapyrrole molecule that functions as a prosthetic group for proteins such as mitochondrial respiratory enzymes. Several studies have suggested that heme has essential functions in the construction and maintenance of the nervous system. In this study, the contents of three biologically important forms of heme (types a, b, and c) and the expression of heme biosynthetic enzymes were examined in differentiating Neuro2a cells. During neuronal differentiation, there were increases in the cellular heme levels and increases in the mRNA levels for the rate-limiting enzymes of heme biosynthesis, such as aminolevulinic acid synthase (ALAS; EC 2.3.1.37) and coproporphyrinogen oxidase (EC 1.3.3.3). With respect to heme contents, heme b increased in the late phase of differentiation, but no apparent increase in heme a or b was observed in the early phase. In contrast, heme c (cytochrome c) markedly increased during the early phase of differentiation. This change preceded the increase in heme b and the up-regulation of the mRNA levels for heme biosynthetic enzymes. This study suggests the up-regulation of heme biosynthesis and differential regulation of the heme a, b, and c levels during neuronal differentiation.
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Affiliation(s)
- Noriko Shinjyo
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033
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35
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Kolluri S, Sadlon T, May B, Bonkovsky H. Haem repression of the housekeeping 5-aminolaevulinic acid synthase gene in the hepatoma cell line LMH. Biochem J 2005; 392:173-80. [PMID: 16033334 PMCID: PMC1317676 DOI: 10.1042/bj20050354] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 07/18/2005] [Accepted: 07/21/2005] [Indexed: 12/13/2022]
Abstract
Haem is essential for the health and function of nearly all cells. 5-Aminolaevulinic acid synthase-1 (ALAS-1) catalyses the first and rate-controlling step of haem biosynthesis. ALAS-1 is repressed by haem and is induced strongly by lipophilic drugs that also induce CYP (cytochrome P450) proteins. We investigated the effects on the avian ALAS-1 gene promoter of a phenobarbital-like chemical, Glut (glutethimide), and a haem synthesis inhibitor, DHA (4,6-dioxoheptanoic acid), using a reporter gene assay in transiently transfected LMH (Leghorn male hepatoma) hepatoma cells. A 9.1 kb cALAS-1 (chicken ALAS-1) promoter-luciferase-reporter construct, was poorly induced by Glut and not by DHA alone, but was synergistically induced by the combination. In contrast, a 3.5 kb promoter ALAS-1 construct was induced by Glut alone, without any further effect of DHA. In addition, exogenous haem (20 microM) repressed the basal and Glut- and DHA-induced activity of luciferase reporter constructs containing 9.1 and 6.3 kb of ALAS-1 5'-flanking region but not the construct containing the first 3.5 kb of promoter sequence. This effect of haem was subsequently shown to be dependent on the -6.3 to -3.5 kb region of the 5'-flanking region of cALAS-1 and requires the native orientation of the region. Two deletion constructs of this approx. 2.8 kb haem-repressive region (1.7 and 1.1 kb constructs) retained haem-dependent repression of basal and drug inductions, suggesting that more than one cis-acting elements are responsible for this haem-dependent repression of ALAS-1. These results demonstrate that there are regulatory regions in the 5'-flanking region of the cALAS-1 gene that respond to haem and provide a basis for further investigations of the molecular mechanisms by which haem down-regulates expression of the ALAS-1 gene.
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Key Words
- 5-aminolaevulinic acid synthase-1 (alas-1)
- 4,6-dioxoheptanoic acid (dha)
- drug induction
- glutethimide
- haem
- lmh cell line
- ala, aminolaevulinic acid
- alas, 5-aminolaevulinic acid synthase
- calas-1, chicken alas-1
- β-gal, β-galactosidase
- dha, 4,6-dioxoheptanoic acid
- dr, hexamer half-site direct repeat
- dres, drug-responsive enhancer sequence
- glut, glutethimide
- ho-1, haem oxygenase-1
- lmh, leghorn male hepatoma
- 5′-utr, 5′-untranslated region
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Affiliation(s)
- Sridevi Kolluri
- †Department of Molecular, Microbial, and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, U.S.A
- ‡The Liver-Biliary-Pancreatic Center, University of Connecticut Health Center, Farmington, CT 06030, U.S.A
| | - Timothy J. Sadlon
- §Children's Health Research Institute, Women's and Children's Hospital, North Adelaide, South Australia 5006, Australia
| | - Brian K. May
- ∥Department of Molecular Biosciences, University of Adelaide, South Australia 5005, Australia
| | - Herbert L. Bonkovsky
- *Department of Medicine, University of Connecticut Health Center, Farmington, CT 06030, U.S.A
- †Department of Molecular, Microbial, and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, U.S.A
- ‡The Liver-Biliary-Pancreatic Center, University of Connecticut Health Center, Farmington, CT 06030, U.S.A
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Davies R, Schuurman A, Barker CR, Clothier B, Chernova T, Higginson FM, Judah DJ, Dinsdale D, Edwards RE, Greaves P, Gant TW, Smith AG. Hepatic gene expression in protoporphyic Fech mice is associated with cholestatic injury but not a marked depletion of the heme regulatory pool. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 166:1041-53. [PMID: 15793285 PMCID: PMC1602388 DOI: 10.1016/s0002-9440(10)62325-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BALB/c Fech(m1Pas) mice have a mutated ferrochelatase gene resulting in protoporphyria that models the hepatic injury occurring sporadically in human erythropoietic protoporphyria. We used this mouse model to study the development of the injury and to compare the dysfunction of heme synthesis with hepatic gene expression of liver metabolism, oxidative stress, and cellular injury/inflammation. From an early age expression of total cytochrome P450 and many of its isoforms was significantly lower than in wild-type mice. However, despite massive accumulation of protoporphyrin in the liver, expression of the main genes controlling heme synthesis and catabolism (Alas1 and Hmox1, respectively) were only modestly affected even in the presence of the cytochrome P450-inducing CAR agonist 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene. In contrast, in BALB/c mice exhibiting griseofulvin-induced hepatic protoporphyria with induction and destruction of cytochrome P450, both Alas1 and Hmox1 genes were markedly up-regulated. Other expression profiles in BALB/c Fech(m1Pas) mice identified roles for oxidative mechanisms in liver injury while modulated gene expression of hepatocyte transport proteins and cholesterol and bile acid synthesis illustrated the development of cholestasis. Subsequent inflammation and cirrhosis were also shown by the up-regulation of cytokine, cell cycling, and procollagen genes. Thus, gene expression profiles studied in Fech(m1Pas) mice may provide candidates for human polymorphisms that explain the sporadic hepatic consequences of erythropoietic protoporphyria.
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Affiliation(s)
- Reginald Davies
- Medical Research Council, Toxicology Unit, Hodgkin Bldg., University of Leicester, Lancaster Rd, Leicester, LE1 9HN, UK
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Roberts AG, Redding SJ, Llewellyn DH. An alternatively-spliced exon in the 5'-UTR of human ALAS1 mRNA inhibits translation and renders it resistant to haem-mediated decay. FEBS Lett 2005; 579:1061-6. [PMID: 15710391 DOI: 10.1016/j.febslet.2004.12.080] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 12/06/2004] [Accepted: 12/28/2004] [Indexed: 01/08/2023]
Abstract
Haem controls its own synthesis in non-erythroid cells primarily by regulation of ALAS1 mRNA stability. Alternative splicing of human ALAS1 generates two mRNAs with different 5'-UTRs: a major one, where exon 1B is omitted, and a minor form containing exon 1B. We show that, unlike the major ALAS1 mRNA, the minor form was resistant to haem-mediated decay. Furthermore, we demonstrate that the ALAS1 5'-UTR alone did not confer haem-mediated decay upon a heterologous mRNA and the inclusion of exon 1B inhibited translation. These data suggest that translation of ALAS1 mRNA itself might be required for destabilisation in response to haem.
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Affiliation(s)
- Andrew G Roberts
- Department of Medical Biochemistry and Immunology, Wales College of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, Wales, UK
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Bonkovsky HL. Neurovisceral porphyrias: what a hematologist needs to know. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2005:24-30. [PMID: 16304355 DOI: 10.1182/asheducation-2005.1.24] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The acute or inducible hepatic porphyrias comprise four inherited disorders of heme biosynthesis. They usually remain asymptomatic for most of the lifespan of individuals who inherit the specific enzyme deficiencies but may cause life-threatening attacks of neurovisceral symptoms. Failure to consider the diagnosis frequently delays effective treatment, and inappropriate diagnostic tests and/or mistaken interpretation of results may lead to misdiagnosis and inappropriate treatment. The four disorders are ALA dehydratase deficiency porphyria, acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria. Other conditions that clinically and biochemically may mimic acute porphyria include lead poisoning and hereditary tyrosinemia type I. The diagnosis of one of these acute porphyric syndromes should be considered in many patients with otherwise unexplained abdominal pain, severe constipation, systemic arterial hypertension, or other characteristic symptoms. Critical to the rapid diagnosis of the three most common of these disorders is demonstration of markedly increased urinary porphobilinogen (PBG) in a single-void urine specimen. The treatment of choice for all but mild attacks of the acute porphyrias is intravenous hemin therapy, which should be started as soon as possible. Intravenous glucose alone is recommended only for mild attacks (no weakness or hyponatremia) or until hemin is available.
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Affiliation(s)
- Herbert L Bonkovsky
- The Liver-Biliary-Pancreatic Center, University of Connecticut, MC-1111, 263 Farmington Avenue, Farmington, CT 06030, USA.
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Lombardo ME, Araujo LS, Batlle A. 5-Aminolevulinic acid synthesis in epimastigotes of Trypanosoma cruzi. Int J Biochem Cell Biol 2003; 35:1263-71. [PMID: 12757763 DOI: 10.1016/s1357-2725(03)00033-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND AND AIMS Trypanosoma cruzi is the causative agent of Chagas disease or American trypanosomiasis. The parasite manifests a nutritional requirement for heme compounds because of its biosynthesis deficiency. The aim of this study has been to investigate the presence of metabolites and enzymes of porphyrin pathway, as well as ALA formation in epimastigotes of T. cruzi, Tulahuén strain, Tul 2 stock. METHODS Succinyl CoA synthetase, 5-aminolevulinic acid (ALA) synthetase, 4,5-dioxovaleric (DOVA) transaminase, ALA dehydratase and porphobilinogenase activities, as well as ALA, porphobilinogen (PBG), free porphyrins and heme content were measured in a parasite cells-free extract. Extracellular content of these metabolites was also determined. RESULTS DOVA, PBG, porphyrins and heme were not detected in acellular extracts of T. cruzi. However ALA was detected both intra- and extracellularly This is the first time that the presence of ALA (98% of intracellularly formed ALA) is demonstrated in the extracellular medium of a parasite culture. Regarding the ALA synthesizing enzymes, DOVA transaminase levels found were low (7.13+/-0.49EU/mg protein), whilst ALA synthetase (ALA-S) activity was undetectable. A compound of non-protein nature, low molecular weight, heat unstable, inhibiting bacterial ALA-S activity was detected in an acellular extract of T. cruzi. This inhibitor could not be identified with either ALA, DOVA or heme. CONCLUSIONS ALA synthesis is functional in the parasite and it would be regulated by the heme levels, both directly and through the inhibitor factor detected. ALA formed can not be metabolized further, because the necessary enzymes are not active, therefore it should be excreted to avoid intracellular cytotoxicity.
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Affiliation(s)
- María Elisa Lombardo
- Centro de Investigaciones sobre Porfirinas y Porfirias-CIPYP (CONICET-FCEN, UBA), Ciudad Universitaria Pabellón II 2do, Piso, 1428 Buenos Aires, Argentina
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40
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van Huystee RB, Sun Y, Lige B. A retrospective look at the cationic peanut peroxidase structure. Crit Rev Biotechnol 2003; 22:335-54. [PMID: 12487424 DOI: 10.1080/07388550290789540] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The cationic peanut peroxidase has been studied in detail, not only with regard to its peptide structure, but also to the sites and role of the three moieties linked to it. Peanut peroxidase lends itself well to a close examination as a potential example for other plant peroxidase studies. It was the first plant peroxidase for which a 3-D structure was derived from crystals, with the glycans intact. Subsequent analysis of peroxidases structures from other plants have not shown great differences to that of the peanut peroxidase. As the period of proteomics follows on the era of genomics, the study of glycans has been brought back into focus. With the potential use of peroxidase as a polymerization agent for industry, there are some aspects of the overall structure that should be kept in mind for successful use of this enzyme. A variety of techniques are now available to assay for these structures/moieties and their roles. Peanut peroxidase data are reviewed in that light, as well as defining some true terms for isozymes. Because a high return of the enzyme in a pure form has been obtained from cultured cells in suspension culture, a brief review of this is also offered.
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Affiliation(s)
- Robert B van Huystee
- Department of Plant Sciences, The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
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Cable EE, Kuhn BR, Isom HC. Effects of modulators of protein phosphorylation on heme metabolism in human hepatic cells: induction of delta-aminolevulinic synthase mRNA and protein by okadaic acid. DNA Cell Biol 2002; 21:323-32. [PMID: 12042071 DOI: 10.1089/104454902753759735] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Effects of modulators of protein phosphorylation on delta-aminolevulinic acid (ALA) synthase and heme oxygenase-1 mRNA were analyzed in the human hepatic cell lines Huh-7 and HepG2 using a quantitative RNase protection assay. Okadaic acid was found to induce ALA synthase mRNA in a concentration-dependent fashion in both Huh-7 and HepG2 cells. The EC(50) for induction of ALA synthase mRNA in Huh-7 cells was 13.5 nM, with maximum increases occurring at okadaic acid concentrations of 25-50 nM. The EC(50) for induction of ALA synthase mRNA in HepG2 cells was 35.5 nM, with maximum increases occurring at okadaic acid concentrations of 50 nM. Concentration-dependent induction of ALA synthase mRNA paralleled the increase in ALA synthase protein. Maximum induction of ALA synthase was observed between 5 and 10 h post-treatment in both cell lines. Induction of ALA synthase mRNA in Huh-7 cells, but not HepG2 cells, was associated with an increase in ALA synthase mRNA stability. Okadaic acid also induced heme oxygenase-1 mRNA in both cell lines, but the magnitude of induction was only twofold, and was rapid and transient. Okadaic acid and phorbol 12-myristate 13-acetate significantly decreased heme-mediated induction of heme oxygenase-1 mRNA in both Huh-7 and HepG2 cells. Wortmannin diminished the heme-mediated induction of heme oxygenase-1 mRNA in HepG2 cells, but not Huh-7 cells. These results report a novel property of okadaic acid to affect heme metabolism in human cell lines.
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Affiliation(s)
- Edward E Cable
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
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Cable EE, Miller TG, Isom HC. Regulation of heme metabolism in rat hepatocytes and hepatocyte cell lines: delta-aminolevulinic acid synthase and heme oxygenase are regulated by different heme-dependent mechanisms. Arch Biochem Biophys 2001; 384:280-95. [PMID: 11368315 DOI: 10.1006/abbi.2000.2117] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regulation of delta-aminolevulinic acid (ALA) synthase and heme oxygenase was analyzed in primary rat hepatocytes and in two immortalized cell lines, CWSV16 and CWSV17 cells. ALA synthase was induced by 4,6-dioxohepatnoic acid (4,6-DHA), a specific inhibitor of ALA dehydratase, in all three systems; however, the induction in CWSV17 cells was greater than in either of the other two systems. Therefore, CWSV17 cells were used to explore the regulation of both enzymes by heme and 4,6-DHA. Data obtained from detailed concentration curves demonstrated that 4,6-DHA induced the activity of ALA synthase once ALA dehydratase activity became rate-limiting for heme biosynthesis. Heme induced heme oxygenase activity with increases occurring at concentrations of 10 microM or greater. Heme blocked the 4,6-DHA-dependent induction of ALA synthase with an EC50 of 1.25 microM. Heme-dependent decreases of ALA synthase mRNA levels occurred more quickly and at lower concentrations than heme-dependent increases of heme oxygenase mRNA levels. ALA synthase mRNA remained at reduced levels for extended periods of time, while the increases in heme oxygenase mRNA were much more transient. The drastic differences in concentrations and times at which heme-dependent effects were observed strongly suggest that two-different heme-dependent mechanisms control the ALA synthase and heme oxygenase mRNAs. In CWSV17 cells, heme decreased the stability of ALA synthase mRNA from 2.5 to 1.3 h, while 4,6-DHA increased the stability of the mRNA to 5.2 h. These studies demonstrate that regulation of ALA synthase mRNA levels by heme in a mammalian system is mediated by a change in ALA synthase mRNA stability. The results reported here demonstrate the function of the regulatory heme pool on both ALA synthase and heme oxygenase in a mammalian hepatocyte system.
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Affiliation(s)
- E E Cable
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey 17033, USA
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Zheng B, Albrecht U, Kaasik K, Sage M, Lu W, Vaishnav S, Li Q, Sun ZS, Eichele G, Bradley A, Lee CC. Nonredundant roles of the mPer1 and mPer2 genes in the mammalian circadian clock. Cell 2001; 105:683-94. [PMID: 11389837 DOI: 10.1016/s0092-8674(01)00380-4] [Citation(s) in RCA: 660] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mice carrying a null mutation in the Period 1 (mPer1) gene were generated using embryonic stem cell technology. Homozygous mPer1 mutants display a shorter circadian period with reduced precision and stability. Mice deficient in both mPer1 and mPer2 do not express circadian rhythms. While mPER2 regulates clock gene expression at the transcriptional level, mPER1 is dispensable for the rhythmic RNA expression of mPer1 and mPer2 and may instead regulate mPER2 at a posttranscriptional level. Studies of clock-controlled genes (CCGs) reveal a complex pattern of regulation by mPER1 and mPER2, suggesting independent controls by the two proteins over some output pathways. Genes encoding key enzymes in heme biosynthesis are under circadian control and are regulated by mPER1 and mPER2. Together, our studies show that mPER1 and mPER2 have distinct and complementary roles in the mouse clock mechanism.
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Affiliation(s)
- B Zheng
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Roberts AG, Elder GH. Alternative splicing and tissue-specific transcription of human and rodent ubiquitous 5-aminolevulinate synthase (ALAS1) genes. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1518:95-105. [PMID: 11267664 DOI: 10.1016/s0167-4781(01)00187-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The rate of haem synthesis in non-erythroid mammalian tissues is controlled by the ubiquitous isoform of 5-aminolevulinate synthase (ALAS1). In order to explore the regulation of mammalian ALAS1 genes, we have investigated the transcription of the human and rat genes. The 17 kb human gene differs from the rat gene in containing an additional untranslated exon that is alternatively spliced to produce a longer, minor mRNA transcript. Relative amounts of the two transcripts were similar in all tissues examined. Analysis of mRNA transcripts in human and rat tissues revealed tissue-specific differences in the use of transcription start sites by closely similar core promoters. In brain, initiation was from sites within and upstream from the TATA box, including an initiator-like element. In liver, initiation was TATA-driven from a single downstream site that appeared to be used exclusively for induction by drugs. Intermediate patterns were observed in other tissues and cell lines. Mutation of the TATA box did not impair transcription in transfected HeLa cells but activated upstream start sites, recapitulating the brain pattern. Our findings indicate that the conformation of the core ALAS1 promoter that directs assembly of the transcription pre-initiation complex may vary between tissues and have implications for understanding the tissue-specific regulated expression of this gene.
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Affiliation(s)
- A G Roberts
- Department of Medical Biochemistry, University of Wales College of Medicine, Heath Park, CF14 4XN, Cardiff, UK
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Braz GR, Abreu L, Masuda H, Oliveira PL. Heme biosynthesis and oogenesis in the blood-sucking bug, Rhodnius prolixus. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2001; 31:359-364. [PMID: 11222945 DOI: 10.1016/s0965-1748(00)00129-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We have previously shown that the pathway of porphyrin synthesis operates in the blood feeding triatomine bug Rhodnius prolixus but not in the cattle tick Boophilus microplus. In the present paper we studied the correlation between heme synthesis and egg development in Rhodnius. There is a sharp increase heme biosynthetic capability in the fat body (160%) and in the ovaries (360%) in response to a blood meal, as evaluated from the activity of the enzyme delta-aminolevulinate dehydratase (EC 4.2.1.24). The in vivo inhibition of ALA-D by succinyl acetone results in a dose dependent decrease of oviposition. Oviposition is recovered when porphobilinogen, the product of the impaired reaction, is added to the succinyl acetone enriched blood. Taken together, these results show that heme biosynthesis is a fundamental event to vitellogenic females. The demand for heme in this metabolic juncture cannot be supplied by the heme eventually absorbed during blood digestion and associated with Rhodnius heme binding protein (RHBP), which is then incorporated into growing oocytes. Inhibition of heme biosynthesis results in lower levels of RHBP in the hemolymph, suggesting that the synthesis of this protein is controlled by heme availability.
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Affiliation(s)
- G R Braz
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, 21941-590, RJ, Rio de Janeiro, Brazil.
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Berg K. Chapter 8 Basic principles of 5-aminolevulinic acid-based photodynamic therapy. COMPREHENSIVE SERIES IN PHOTOSCIENCES 2001. [DOI: 10.1016/s1568-461x(01)80112-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Jover R, Hoffmann F, Scheffler-Koch V, Lindberg RL. Limited heme synthesis in porphobilinogen deaminase-deficient mice impairs transcriptional activation of specific cytochrome P450 genes by phenobarbital. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:7128-37. [PMID: 11106424 DOI: 10.1046/j.1432-1327.2000.01815.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Heme is not only a very important prosthetic group that modulates the structure and activity of heme proteins but also a regulatory molecule that controls metabolic pathways and the biosynthesis of various proteins. However, investigation into heme regulatory effects in higher vertebrates has been hampered by the lack of a suitable animal model. A knockout mouse with targeted disruption of porphobilinogen deaminase, the third enzyme of the heme pathway, has been generated in our laboratory and used in the present study as an in vivo model of heme deficiency to explore diverse heme regulatory properties. In this model with a defined heme disturbance, we observed a superinductive response of delta-aminolevulinate synthase, the first enzyme in heme synthesis, after phenobarbital treatment. We also found that limited heme is associated with decreased induction of cytochrome P450 by phenobarbital as a consequence of impaired gene transcription. This inhibitory effect is isoenzyme-specific, being significant for cyp2a5. The activity and mRNA level of this particular cytochrome P450 are significantly lower in the phenobarbital-induced porphobilinogen deaminase-deficient mice (55% and 43%, respectively), but its expression can be restored to normal values when exogenous heme is administered. Other heme proteins, namely neuronal nitric oxide synthase and soluble guanylate cyclase, function normally in mice with limited heme. Our results demonstrate that the expression of various heme proteins is differentially regulated in conditions of reduced heme availability. Moreover, our findings emphasize the importance of heme protein function in the genesis of pathophysiological manifestations in acute intermittent porphyria.
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Affiliation(s)
- R Jover
- Biozentrum, University of Basel, Switzerland
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48
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Abstract
The hepatic cytosolic hemoprotein tryptophan 2,3-dioxygenase (TDO) is the rate-limiting enzyme in tryptophan catabolism and thus plays a key role in regulating the physiological flux of tryptophan into relevant metabolic pathways. The TDO protein is induced by corticosteroids such as dexamethasone (DEX) and is stabilized by its prosthetic heme. In rats, acute chemically induced hepatic heme depletion reduces the functional hepatic TDO levels to 25-30% of basal levels within 1 h, and this decrease persists beyond 28 h of heme depletion at which time only 25-30% of the protein is available for heme incorporation. Since this could stem from impaired de novo synthesis and/or instability of the newly synthesized apoTDO protein in the absence of heme, we examined the specific role of heme in these events in a previously validated rat model of acute hepatic heme depletion triggered by the P450 suicide substrate 3, 5-dicarbethoxy 2,6-dimethyl-4-ethyl-1,4-dihydropyridine. We now show that exogenous heme can reverse the functional impairment of the enzyme observed during hepatic heme depletion and fully restore the impaired DEX-mediated induction of the enzyme to normal. Furthermore, through Northern/slot blot analyses coupled with nuclear run-on studies, we now document that this heme regulation of TDO is exerted primarily at the transcriptional level. Immunoblotting analyses also reveal corresponding changes in the TDO protein, thereby establishing that heme is necessary for DEX-inducible TDO mRNA transcription and subsequent translation. Thus, the TDO gene may contain heme-regulatory elements in addition to the reported glucocorticoid-responsive elements. Together, these findings suggest that clinically, hepatic heme deficiency may enhance the tryptophan flux into synthetic (serotonergic) pathways, not only by depriving prosthetic heme for a functionally competent TDO hemoprotein, its primary catabolic enzyme, but also by impairing the de novo synthesis of this enzyme.
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Affiliation(s)
- S Ren
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94143, USA
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Kolluri S, Elbirt KK, Bonkovsky HL. Heme biosynthesis in a chicken hepatoma cell line (LMH): comparison with primary chick embryo liver cells (CELC). BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1472:658-67. [PMID: 10564780 DOI: 10.1016/s0304-4165(99)00159-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
5-Aminolevulinic acid synthase (ALA synthase), the rate-controlling enzyme of hepatic heme biosynthesis, is feed-back repressed by heme. In the liver, chemicals such as barbiturates markedly induce ALA synthase, especially in the presence of partial defects of heme biosynthesis. The inducibility and regulation of ALA synthase have been investigated using a variety of models, including intact animals and liver cell culture systems. A widely used model that closely approximates what occurs in vivo and in humans is that of primary cultures of chick embryo liver cells (CELCs). However, CELCs have some limitations: the cells obtained are somewhat heterogeneous; isolation and culture must be repeated every week resulting in weekly variations; and cells are short-lived limiting the feasibility of time-course and transfection studies. The aim of this study was to determine if LMH cells, a chick hepatoma cell line, are a good model comparable to that of CELCs. In both cells similar patterns of response of, ALA synthase activities and mRNA levels, and of porphyrin accumulation were obtained following treatments known to affect heme biosynthesis. Similarly, heme repressed ALA synthase mRNA levels in both cell types and ALA synthase activities in LMH cells. We conclude that LMH cells are a useful model for the study of hepatic heme biosynthesis and regulation of ALA synthase.
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Affiliation(s)
- S Kolluri
- Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
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Abstract
Heme is a complex of iron with protoporphyrin IX that is essential for the function of all aerobic cells. Heme serves as the prosthetic group of numerous hemoproteins (eg, hemoglobin, myoglobin, cytochromes, guanylate cyclase, and nitric oxide synthase) and plays an important role in controlling protein synthesis and cell differentiation. Cellular heme levels are tightly controlled; this is achieved by a fine balance between heme biosynthesis and catabolism by the enzyme heme oxygenase. On a per-cell basis, the rate of heme synthesis in the developing erythroid cells is at least 1 order of magnitude higher than in the liver, which is in turn the second most active heme producer in the organism. Differences in iron metabolism and in genes for 5-aminolevulinic acid synthase (ALA-S, the first enzyme in heme biosynthesis) are responsible for the differences in regulation and rates of heme synthesis in erythroid and nonerythroid cells. There are 2 different genes for ALA-S, one of which is expressed ubiquitously (ALA-S1), whereas the expression of the other (ALA-S2) is specific to erythroid cells. Because the 5'-untranslated region of the erythroid-specific ALA-S2 mRNA contains the iron-responsive element, a cis-acting sequence responsible for translational induction of erythroid ALA-S2 by iron, the availability of iron controls protoporphyrin IX levels in hemoglobin-synthesizing cells. In nonerythroid cells, the rate-limiting step of heme production is catalyzed by ALA-S1, whose synthesis is feedback-inhibited by heme. On the other hand, in erythroid cells, heme does not inhibit either the activity or the synthesis of ALA-S but does inhibit cellular iron acquisition from transferrin without affecting its utilization for heme synthesis. This negative feedback is likely to explain the mechanism by which the availability of transferrin iron limits heme synthesis rate. Moreover, in erythroid cells heme seems to enhance globin gene transcription, is essential for globin translation, and supplies the prosthetic group for hemoglobin assembly. Heme may also be involved in the expression of other erythroid-specific proteins. Furthermore, heme seems to play a role in regulating either transcription, translation, processing, assembly, or stability of hemoproteins in nonerythroid cells. Heme oxygenase, which catalyzes heme degradation, seems to be an important enzymatic antioxidant system, probably by providing biliverdin, which is an antioxidant agent.
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Affiliation(s)
- P Ponka
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.
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