151
|
Lewerenz J, Maher P. Control of redox state and redox signaling by neural antioxidant systems. Antioxid Redox Signal 2011; 14:1449-65. [PMID: 20812872 DOI: 10.1089/ars.2010.3600] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The glutathione/glutathione disulfide (GSH/GSSG) redox pair forms the major redox couple in cells and as such plays a critical role in regulating redox-dependent cellular functions. Not only does GSH act as an antioxidant but it can also modulate the activity of a variety of different proteins. An impairment in GSH status is thought to be the precipitating event in a wide range of neurological disorders. Therefore, understanding how to maintain GSH in the CNS could provide a valuable therapeutic approach. Intracellular GSH levels are regulated by a complex series of pathways that include substrate transport and availability, rates of synthesis and regeneration, GSH utilization, and GSH efflux. To date, the most effective approaches for maintaining GSH levels in the CNS include enhancing cyst(e)ine uptake both directly and indirectly via transcriptional upregulation of system x(c)(-), increasing GSH synthesis via transcriptional upregulation of the rate limiting enzyme in GSH biosynthesis, and decreasing GSH utilization. Among the transcription factors that play critical roles in GSH metabolism are NF-E2-related factor 2 (Nrf2) and activating transcription factor 4 (ATF4). Thus, compounds that can upregulate these transcription factors may be particularly useful in promoting the functional maintenance of the CNS through their effects on GSH metabolism.
Collapse
Affiliation(s)
- Jan Lewerenz
- Department for Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | |
Collapse
|
152
|
Patel VP, Chu CT. Nuclear transport, oxidative stress, and neurodegeneration. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2011; 4:215-229. [PMID: 21487518 PMCID: PMC3071655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 02/27/2011] [Indexed: 05/30/2023]
Abstract
Trafficking of transcription factors between the cytoplasm and the nucleus is an essential aspect of signal transduction, which is particularly challenging in neurons due to their highly polarized structure. Disruption in the subcellular localization of many proteins, including transcription factors, is observed in affected neurons of human neurodegenerative diseases. In these diseases, there is also growing evidence supporting alterations in nuclear transport as potential mechanisms underlying the observed mislocalization of proteins. Oxidative stress, which plays a key pathogenic role in these diseases, has also been associated with significant alterations in nuclear transport. After providing an overview of the major nuclear import and export pathways and discussing the impact of oxidative injury on nuclear trafficking of proteins, this review synthesizes emerging evidence for altered nuclear transport as a possible mechanism in the pathogenesis of neurodegenerative diseases. Potential strategies to overcome such deficits are also discussed.
Collapse
Affiliation(s)
- Vivek P Patel
- Center for Neuroscience at the University of Pittsburgh, PA, USA
| | | |
Collapse
|
153
|
Guccini I, Serio D, Condò I, Rufini A, Tomassini B, Mangiola A, Maira G, Anile C, Fina D, Pallone F, Mongiardi MP, Levi A, Ventura N, Testi R, Malisan F. Frataxin participates to the hypoxia-induced response in tumors. Cell Death Dis 2011; 2:e123. [PMID: 21368894 PMCID: PMC3101705 DOI: 10.1038/cddis.2011.5] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 01/13/2011] [Accepted: 01/19/2011] [Indexed: 01/30/2023]
Abstract
Defective expression of frataxin is responsible for the degenerative disease Friedreich's ataxia. Frataxin is a protein required for cell survival since complete knockout is lethal. Frataxin protects tumor cells against oxidative stress and apoptosis but also acts as a tumor suppressor. The molecular bases of this apparent paradox are missing. We therefore sought to investigate the pathways through which frataxin enhances stress resistance in tumor cells. We found that frataxin expression is upregulated in several tumor cell lines in response to hypoxic stress, a condition often associated with tumor progression. Moreover, frataxin upregulation in response to hypoxia is dependent on hypoxia-inducible factors expression and modulates the activation of the tumor-suppressor p53. Importantly, we show for the first time that frataxin is in fact increased in human tumors in vivo. These results show that frataxin participates to the hypoxia-induced stress response in tumors, thus implying that modulation of its expression could have a critical role in tumor cell survival and/or progression.
Collapse
Affiliation(s)
- I Guccini
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| | - D Serio
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| | - I Condò
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| | - A Rufini
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| | - B Tomassini
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| | - A Mangiola
- Department of Neurosurgery, Catholic University School of Medicine, Rome, Italy
| | - G Maira
- Department of Neurosurgery, Catholic University School of Medicine, Rome, Italy
| | - C Anile
- Department of Neurosurgery, Catholic University School of Medicine, Rome, Italy
| | - D Fina
- Department of Internal Medicine, University ‘Tor Vergata', Rome, Italy
| | - F Pallone
- Department of Internal Medicine, University ‘Tor Vergata', Rome, Italy
| | - M P Mongiardi
- National Research Council of Italy, Cell Biology and Neurobiology Institute and IRCCS Fondazione Santa Lucia, Rome, Italy
| | - A Levi
- National Research Council of Italy, Cell Biology and Neurobiology Institute and IRCCS Fondazione Santa Lucia, Rome, Italy
| | - N Ventura
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| | - R Testi
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| | - F Malisan
- Department of Experimental Medicine and Biochemical Sciences, Laboratory of Signal Transduction, University ‘Tor Vergata', Rome, Italy
| |
Collapse
|
154
|
Gakh O, Bedekovics T, Duncan SF, Smith DY, Berkholz DS, Isaya G. Normal and Friedreich ataxia cells express different isoforms of frataxin with complementary roles in iron-sulfur cluster assembly. J Biol Chem 2010; 285:38486-501. [PMID: 20889968 PMCID: PMC2992281 DOI: 10.1074/jbc.m110.145144] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 09/30/2010] [Indexed: 11/06/2022] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive degenerative disease caused by insufficient expression of frataxin (FXN), a mitochondrial iron-binding protein required for Fe-S cluster assembly. The development of treatments to increase FXN levels in FRDA requires elucidation of the steps involved in the biogenesis of functional FXN. The FXN mRNA is translated to a precursor polypeptide that is transported to the mitochondrial matrix and processed to at least two forms, FXN(42-210) and FXN(81-210). Previous reports suggested that FXN(42-210) is a transient processing intermediate, whereas FXN(81-210) represents the mature protein. However, we find that both FXN(42-210) and FXN(81-210) are present in control cell lines and tissues at steady-state, and that FXN(42-210) is consistently more depleted than FXN(81-210) in samples from FRDA patients. Moreover, FXN(42-210) and FXN(81-210) have strikingly different biochemical properties. A shorter N terminus correlates with monomeric configuration, labile iron binding, and dynamic contacts with components of the Fe-S cluster biosynthetic machinery, i.e. the sulfur donor complex NFS1·ISD11 and the scaffold ISCU. Conversely, a longer N terminus correlates with the ability to oligomerize, store iron, and form stable contacts with NFS1·ISD11 and ISCU. Monomeric FXN(81-210) donates Fe(2+) for Fe-S cluster assembly on ISCU, whereas oligomeric FXN(42-210) donates either Fe(2+) or Fe(3+). These functionally distinct FXN isoforms seem capable to ensure incremental rates of Fe-S cluster synthesis from different mitochondrial iron pools. We suggest that the levels of both isoforms are relevant to FRDA pathophysiology and that the FXN(81-210)/FXN(42-210) molar ratio should provide a useful parameter to optimize FXN augmentation and replacement therapies.
Collapse
Affiliation(s)
- Oleksandr Gakh
- From the Departments of Pediatric & Adolescent Medicine and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Tibor Bedekovics
- From the Departments of Pediatric & Adolescent Medicine and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Samantha F. Duncan
- From the Departments of Pediatric & Adolescent Medicine and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Douglas Y. Smith
- From the Departments of Pediatric & Adolescent Medicine and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Donald S. Berkholz
- From the Departments of Pediatric & Adolescent Medicine and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Grazia Isaya
- From the Departments of Pediatric & Adolescent Medicine and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| |
Collapse
|
155
|
Santos R, Lefevre S, Sliwa D, Seguin A, Camadro JM, Lesuisse E. Friedreich ataxia: molecular mechanisms, redox considerations, and therapeutic opportunities. Antioxid Redox Signal 2010; 13:651-90. [PMID: 20156111 PMCID: PMC2924788 DOI: 10.1089/ars.2009.3015] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 02/08/2010] [Accepted: 02/14/2010] [Indexed: 12/14/2022]
Abstract
Mitochondrial dysfunction and oxidative damage are at the origin of numerous neurodegenerative diseases like Friedreich ataxia and Alzheimer and Parkinson diseases. Friedreich ataxia (FRDA) is the most common hereditary ataxia, with one individual affected in 50,000. This disease is characterized by progressive degeneration of the central and peripheral nervous systems, cardiomyopathy, and increased incidence of diabetes mellitus. FRDA is caused by a dynamic mutation, a GAA trinucleotide repeat expansion, in the first intron of the FXN gene. Fewer than 5% of the patients are heterozygous and carry point mutations in the other allele. The molecular consequences of the GAA triplet expansion is transcription silencing and reduced expression of the encoded mitochondrial protein, frataxin. The precise cellular role of frataxin is not known; however, it is clear now that several mitochondrial functions are not performed correctly in patient cells. The affected functions include respiration, iron-sulfur cluster assembly, iron homeostasis, and maintenance of the redox status. This review highlights the molecular mechanisms that underlie the disease phenotypes and the different hypothesis about the function of frataxin. In addition, we present an overview of the most recent therapeutic approaches for this severe disease that actually has no efficient treatment.
Collapse
Affiliation(s)
- Renata Santos
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Sophie Lefevre
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
- University Pierre et Marie Curie, Paris, France
| | - Dominika Sliwa
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Alexandra Seguin
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Jean-Michel Camadro
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Emmanuel Lesuisse
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| |
Collapse
|
156
|
Torgovnick A, Schiavi A, Testi R, Ventura N. A role for p53 in mitochondrial stress response control of longevity in C. elegans. Exp Gerontol 2010; 45:550-7. [PMID: 20172019 DOI: 10.1016/j.exger.2010.02.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 01/29/2010] [Accepted: 02/12/2010] [Indexed: 11/24/2022]
Abstract
As in the case of aging, many degenerative disorders also result from progressive mitochondrial deterioration and cellular damage accumulation. Therefore, preventing damage accumulation may delay aging and help to prevent degenerative disorders, especially those associated with mitochondrial dysfunction. In the nematode Caenorhabditis elegans a mild mitochondrial dysfunction prolongs the lifespan. We previously proposed that, following a mild mitochondrial dysfunction, protective stress responses are activated in a hormetic-like fashion, and ultimately account for extended animal's lifespan. We recently showed that in C. elegans, lifespan extension induced by reduced expression of different mitochondrial proteins involved in electron transport chain functionality requires p53/cep-1. In this paper we find that reducing the expression of frataxin, the protein defective in patients with Friedreich's ataxia, triggers a complex stress response, and that the associated induction of the antioxidant glutathione-S-transferase is regulated by cep-1. Given the high percentage of homology between human and nematode genes and the conservation of fundamental intracellular pathways between the two species, identification of molecular mechanisms activated in response to frataxin suppression in C. elegans may suggest novel therapeutic approaches to prevent the accumulation of irreversible damage and the consequent appearance of symptoms in Friedreich's ataxia and possibly other human mitochondrial-associated diseases. The same pathways could be exploitable for delaying the aging process ascribed to mitochondrial degeneration.
Collapse
Affiliation(s)
- Alessandro Torgovnick
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Rome, Italy
| | | | | | | |
Collapse
|
157
|
Navarro JA, Ohmann E, Sanchez D, Botella JA, Liebisch G, Moltó MD, Ganfornina MD, Schmitz G, Schneuwly S. Altered lipid metabolism in a Drosophila model of Friedreich's ataxia. Hum Mol Genet 2010; 19:2828-40. [PMID: 20460268 PMCID: PMC7108586 DOI: 10.1093/hmg/ddq183] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 04/08/2010] [Accepted: 05/01/2010] [Indexed: 12/21/2022] Open
Abstract
Friedreich's ataxia (FRDA) is the most common form of autosomal recessive ataxia caused by a deficit in the mitochondrial protein frataxin. Although demyelination is a common symptom in FRDA patients, no multicellular model has yet been developed to study the involvement of glial cells in FRDA. Using the recently established RNAi lines for targeted suppression of frataxin in Drosophila, we were able to study the effects of general versus glial-specific frataxin downregulation. In particular, we wanted to study the interplay between lowered frataxin content, lipid accumulation and peroxidation and the consequences of these effects on the sensitivity to oxidative stress and fly fitness. Interestingly, ubiquitous frataxin reduction leads to an increase in fatty acids catalyzing an enhancement of lipid peroxidation levels, elevating the intracellular toxic potential. Specific loss of frataxin in glial cells triggers a similar phenotype which can be visualized by accumulating lipid droplets in glial cells. This phenotype is associated with a reduced lifespan, an increased sensitivity to oxidative insult, neurodegenerative effects and a serious impairment of locomotor activity. These symptoms fit very well with our observation of an increase in intracellular toxicity by lipid peroxides. Interestingly, co-expression of a Drosophila apolipoprotein D ortholog (glial lazarillo) has a strong protective effect in our frataxin models, mainly by controlling the level of lipid peroxidation. Our results clearly support a strong involvement of glial cells and lipid peroxidation in the generation of FRDA-like symptoms.
Collapse
Affiliation(s)
- Juan A. Navarro
- Institute of Zoology, Universitaetsstrasse 31, University of Regensburg, 93040 Regensburg, Germany
| | - Elisabeth Ohmann
- Institute of Zoology, Universitaetsstrasse 31, University of Regensburg, 93040 Regensburg, Germany
| | - Diego Sanchez
- Departamento de Bioquímica y Biología Molecular y Fisiología, Instituto de Biología y Genética Molecular, C/Sanz y Forés s/n, Universidad de Valladolid-CSIC, 47003 Valladolid, Spain
| | - José A. Botella
- Institute of Zoology, Universitaetsstrasse 31, University of Regensburg, 93040 Regensburg, Germany
| | - Gerhard Liebisch
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany and
| | - María D. Moltó
- Department of Genetics, Universidad de Valencia, CIBERSAM, 46100 Burjassot, Valencia, Spain
| | - María D. Ganfornina
- Departamento de Bioquímica y Biología Molecular y Fisiología, Instituto de Biología y Genética Molecular, C/Sanz y Forés s/n, Universidad de Valladolid-CSIC, 47003 Valladolid, Spain
| | - Gerd Schmitz
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany and
| | - Stephan Schneuwly
- Institute of Zoology, Universitaetsstrasse 31, University of Regensburg, 93040 Regensburg, Germany
| |
Collapse
|
158
|
Armstrong JS, Khdour O, Hecht SM. Does oxidative stress contribute to the pathology of Friedreich's ataxia? A radical question. FASEB J 2010; 24:2152-63. [PMID: 20219987 DOI: 10.1096/fj.09-143222] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Friedreich's ataxia (FRDA) is a hereditary neurodegenerative disease that frequently culminates in cardiac failure at an early age. FRDA is believed to arise from reduced synthesis of the mitochondrial iron chaperone frataxin due to impaired gene transcription, which leads to mitochondrial iron accumulation, dysfunction of mitochondrial Fe-S containing enzymes, and increased Fenton-mediated free radical production. Recent reports have challenged this generally accepted hypothesis, by suggesting that the oxidative stress component in FRDA is minimal and thereby questioning the benefit of antioxidant therapeutic strategies. We suggest that this apparent paradox results from the radically divergent chemistries of the participating reactive oxygen species (ROS), the major cellular subcompartments involved and the overall cellular responses to ROS. In this review, we consider these factors and conclude that oxidative stress does constitute a major contributing factor to FRDA pathology. This reaffirms the idea that the rational design of specific small molecule multifunctional antioxidants will benefit FRDA patients.
Collapse
Affiliation(s)
- Jeffrey S Armstrong
- Center for BioEnergetics, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
| | | | | |
Collapse
|
159
|
Seguin A, Sutak R, Bulteau AL, Garcia-Serres R, Oddou JL, Lefevre S, Santos R, Dancis A, Camadro JM, Latour JM, Lesuisse E. Evidence that yeast frataxin is not an iron storage protein in vivo. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1802:531-8. [PMID: 20307653 DOI: 10.1016/j.bbadis.2010.03.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 03/14/2010] [Accepted: 03/16/2010] [Indexed: 11/29/2022]
Abstract
Yeast cells deficient in the yeast frataxin homolog (Yfh1p) accumulate iron in their mitochondria. Whether this iron is toxic, however, remains unclear. We showed that large excesses of iron in the growth medium did not inhibit growth and did not decrease cell viability. Increasing the ratio of mitochondrial iron-to-Yfh1p by decreasing the steady-state level of Yfh1p to less than 100 molecules per cell had very few deleterious effects on cell physiology, even though the mitochondrial iron concentration greatly exceeded the iron-binding capacity of Yfh1p in these conditions. Mössbauer spectroscopy and FPLC analyses of whole mitochondria or of isolated mitochondrial matrices showed that the chemical and biochemical forms of the accumulated iron in mitochondria of mutant yeast strains (Deltayfh1, Deltaggc1 and Deltassq1) displayed a nearly identical distribution. This was also the case for Deltaggc1 cells, in which Yfh1p was overproduced. In these mitochondria, most of the iron was insoluble, and the ratio of soluble-to-insoluble iron did not change when the amount of Yfh1p was increased up to 4500 molecules per cell. Our results do not privilege the hypothesis of Yfh1p being an iron storage protein in vivo.
Collapse
Affiliation(s)
- Alexandra Seguin
- Laboratoire Mitochondries, Métaux et Stress oxydant, Institut Jacques Monod, CNRS-Université Paris Diderot, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
160
|
Schmucker S, Puccio H. Understanding the molecular mechanisms of Friedreich's ataxia to develop therapeutic approaches. Hum Mol Genet 2010; 19:R103-10. [PMID: 20413654 DOI: 10.1093/hmg/ddq165] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by reduced expression of the mitochondrial protein frataxin. The physiopathological consequences of frataxin deficiency are a severe disruption of iron-sulfur cluster biosynthesis, mitochondrial iron overload coupled to cellular iron dysregulation and an increased sensitivity to oxidative stress. Frataxin is a highly conserved protein, which has been suggested to participate in a variety of different roles associated with cellular iron homeostasis. The present review discusses recent advances that have made crucial contributions in understanding the molecular mechanisms underlying FRDA and in advancements toward potential novel therapeutic approaches. Owing to space constraints, this review will focus on the most commonly accepted and solid molecular and biochemical studies concerning the function of frataxin and the physiopathology of the disease. We invite the reader to read the following reviews to have a more exhaustive overview of the field [Pandolfo, M. and Pastore, A. (2009) The pathogenesis of Friedreich ataxia and the structure and function of frataxin. J. Neurol., 256 (Suppl. 1), 9-17; Gottesfeld, J.M. (2007) Small molecules affecting transcription in Friedreich ataxia. Pharmacol. Ther., 116, 236-248; Pandolfo, M. (2008) Drug insight: antioxidant therapy in inherited ataxias. Nat. Clin. Pract. Neurol., 4, 86-96; Puccio, H. (2009) Multicellular models of Friedreich ataxia. J. Neurol., 256 (Suppl. 1), 18-24].
Collapse
Affiliation(s)
- Stéphane Schmucker
- Institut de Genetique et de Biologie Moleculaire et Cellulaire, BP10142, IllkirchF-67400, France
| | | |
Collapse
|
161
|
Bénit P, El-Khoury R, Schiff M, Sainsard-Chanet A, Rustin P. Genetic background influences mitochondrial function: modeling mitochondrial disease for therapeutic development. Trends Mol Med 2010; 16:210-7. [PMID: 20382561 DOI: 10.1016/j.molmed.2010.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/11/2010] [Accepted: 03/15/2010] [Indexed: 12/21/2022]
Abstract
Genetic background strongly influences the phenotype of human mitochondrial diseases. Mitochondrial biogenesis and function require up to 1500 nuclear genes, providing myriad opportunities for effects on disease expression. Phenotypic variability, combined with relative rarity, constitutes a major obstacle to establish cohorts for clinical trials. Animal models are, therefore, potentially valuable. However, several of these show no or very mild disease phenotypes compared with patients and can not be used for therapeutic studies. One reason might be the insufficient attention paid to the need for genetic diversity in order to capture the effects of genetic background on disease expression. Here, we use data from various models to emphasize the need to preserve genetic diversity when studying mitochondrial disease phenotypes or drug effects.
Collapse
|
162
|
Marmolino D, Manto M, Acquaviva F, Vergara P, Ravella A, Monticelli A, Pandolfo M. PGC-1alpha down-regulation affects the antioxidant response in Friedreich's ataxia. PLoS One 2010; 5:e10025. [PMID: 20383327 PMCID: PMC2850922 DOI: 10.1371/journal.pone.0010025] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Accepted: 03/16/2010] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Cells from individuals with Friedreich's ataxia (FRDA) show reduced activities of antioxidant enzymes and cannot up-regulate their expression when exposed to oxidative stress. This blunted antioxidant response may play a central role in the pathogenesis. We previously reported that Peroxisome Proliferator Activated Receptor Gamma (PPARgamma) Coactivator 1-alpha (PGC-1alpha), a transcriptional master regulator of mitochondrial biogenesis and antioxidant responses, is down-regulated in most cell types from FRDA patients and animal models. METHODOLOGY/PRINCIPAL FINDINGS We used primary fibroblasts from FRDA patients and the knock in-knock out animal model for the disease (KIKO mouse) to determine basal superoxide dismutase 2 (SOD2) levels and the response to oxidative stress induced by the addition of hydrogen peroxide. We measured the same parameters after pharmacological stimulation of PGC-1alpha. Compared to control cells, PGC-1alpha and SOD2 levels were decreased in FRDA cells and did not change after addition of hydrogen peroxide. PGC-1alpha direct silencing with siRNA in control fibroblasts led to a similar loss of SOD2 response to oxidative stress as observed in FRDA fibroblasts. PGC-1alpha activation with the PPARgamma agonist (Pioglitazone) or with a cAMP-dependent protein kinase (AMPK) agonist (AICAR) restored normal SOD2 induction. Treatment of the KIKO mice with Pioglitazone significantly up-regulates SOD2 in cerebellum and spinal cord. CONCLUSIONS/SIGNIFICANCE PGC-1alpha down-regulation is likely to contribute to the blunted antioxidant response observed in cells from FRDA patients. This response can be restored by AMPK and PPARgamma agonists, suggesting a potential therapeutic approach for FRDA.
Collapse
Affiliation(s)
- Daniele Marmolino
- Laboratoire de Neurologie Expérimentale, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Mario Manto
- Laboratoire de Neurologie Expérimentale, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Fonds National de la Recherche Scientifique (FNRS), Brussels, Belgium
| | - Fabio Acquaviva
- Department of Cellular and Molecular Biology, University of Naples “Federico II”, Naples, Italy
| | - Paola Vergara
- Department of Cellular and Molecular Biology, University of Naples “Federico II”, Naples, Italy
| | - Ajay Ravella
- Laboratoire de Neurologie Expérimentale, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | | | - Massimo Pandolfo
- Laboratoire de Neurologie Expérimentale, Université Libre de Bruxelles (ULB), Brussels, Belgium
| |
Collapse
|
163
|
Sykiotis GP, Bohmann D. Stress-activated cap'n'collar transcription factors in aging and human disease. Sci Signal 2010; 3:re3. [PMID: 20215646 DOI: 10.1126/scisignal.3112re3] [Citation(s) in RCA: 603] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cap'n'collar (Cnc) transcription factors are conserved in metazoans and have important developmental and homeostatic functions. The vertebrate Nrf1, Nrf2, and Nrf3; the Caenorhabditis elegans SKN-1; and the Drosophila CncC comprise a subgroup of Cnc factors that mediate adaptive responses to cellular stress. The most studied stress-activated Cnc factor is Nrf2, which orchestrates the transcriptional response of cells to oxidative stressors and electrophilic xenobiotics. In rodent models, signaling by Nrf2 defends against oxidative stress and aging-associated disorders, such as neurodegeneration, respiratory diseases, and cancer. In humans, polymorphisms that decrease Nrf2 abundance have been associated with various pathologies of the skin, respiratory system, and digestive tract. In addition to preventing disease in rodents and humans, Cnc factors have life-span-extending and anti-aging functions in invertebrates. However, despite the pro-longevity and antioxidant roles of stress-activated Cnc factors, their activity paradoxically declines in aging model organisms and in humans suffering from progressive respiratory disease or neurodegeneration. We review the roles and regulation of stress-activated Cnc factors across species, present all reported instances in which their activity is paradoxically decreased in aging and disease, and discuss the possibility that the pharmacological restoration of Nrf2 signaling may be useful in the prevention and treatment of age-related diseases.
Collapse
Affiliation(s)
- Gerasimos P Sykiotis
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA.
| | | |
Collapse
|
164
|
Haugen AC, Di Prospero NA, Parker JS, Fannin RD, Chou J, Meyer JN, Halweg C, Collins JB, Durr A, Fischbeck K, Van Houten B. Altered gene expression and DNA damage in peripheral blood cells from Friedreich's ataxia patients: cellular model of pathology. PLoS Genet 2010; 6:e1000812. [PMID: 20090835 PMCID: PMC2799513 DOI: 10.1371/journal.pgen.1000812] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 12/10/2009] [Indexed: 12/02/2022] Open
Abstract
The neurodegenerative disease Friedreich's ataxia (FRDA) is the most common autosomal-recessively inherited ataxia and is caused by a GAA triplet repeat expansion in the first intron of the frataxin gene. In this disease, transcription of frataxin, a mitochondrial protein involved in iron homeostasis, is impaired, resulting in a significant reduction in mRNA and protein levels. Global gene expression analysis was performed in peripheral blood samples from FRDA patients as compared to controls, which suggested altered expression patterns pertaining to genotoxic stress. We then confirmed the presence of genotoxic DNA damage by using a gene-specific quantitative PCR assay and discovered an increase in both mitochondrial and nuclear DNA damage in the blood of these patients (p<0.0001, respectively). Additionally, frataxin mRNA levels correlated with age of onset of disease and displayed unique sets of gene alterations involved in immune response, oxidative phosphorylation, and protein synthesis. Many of the key pathways observed by transcription profiling were downregulated, and we believe these data suggest that patients with prolonged frataxin deficiency undergo a systemic survival response to chronic genotoxic stress and consequent DNA damage detectable in blood. In conclusion, our results yield insight into the nature and progression of FRDA, as well as possible therapeutic approaches. Furthermore, the identification of potential biomarkers, including the DNA damage found in peripheral blood, may have predictive value in future clinical trials.
Collapse
Affiliation(s)
- Astrid C. Haugen
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Nicholas A. Di Prospero
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - Joel S. Parker
- Expression Analysis, Durham, North Carolina, United States of America
| | - Rick D. Fannin
- Laboratory of Toxicogenomics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Jeff Chou
- Laboratory of Toxicogenomics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Joel N. Meyer
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Christopher Halweg
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Jennifer B. Collins
- Laboratory of Toxicogenomics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Alexandra Durr
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Université Pierre et Marie Curie, Paris, France
- Département de Génétique et Embryologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - Kenneth Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- University of Pittsburgh Cancer Institute, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| |
Collapse
|
165
|
Schiff M, Loublier S, Coulibaly A, Bénit P, Ogier de Baulny H, Rustin P. Mitochondria and diabetes mellitus: untangling a conflictive relationship? J Inherit Metab Dis 2009; 32:684-698. [PMID: 19821144 DOI: 10.1007/s10545-009-1263-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 08/19/2009] [Accepted: 08/25/2009] [Indexed: 01/19/2023]
Abstract
Diabetes mellitus is occasionally observed in patients with skeletal muscle respiratory chain deficiency, suggesting that skeletal muscle mitochondrial dysfunction might play a pathogenic role in type 2 diabetes (T2D). In support of this hypothesis, decreased muscle mitochondrial activity has been reported in T2D patients and in mouse models of diabetes. However, recent work by several groups suggests that decreased muscle mitochondrial function may be a consequence rather than a cause of diabetes, since decreased mitochondrial function in mice affords protection from diabetes and obesity. We review the data on this controversial but important issue of potential links between mitochondrial dysfunction and diabetes.
Collapse
Affiliation(s)
- M Schiff
- Hôpital Robert Debré, Paris, France
- Université Paris 7, Faculté de médecine Denis Diderot, IFR02, Paris, France
- Centre de référence Maladies Métaboliques, Hôpital Robert Debré, APHP, Paris, France
| | - S Loublier
- Hôpital Robert Debré, Paris, France
- Université Paris 7, Faculté de médecine Denis Diderot, IFR02, Paris, France
| | - A Coulibaly
- Hôpital Robert Debré, Paris, France
- Université Paris 7, Faculté de médecine Denis Diderot, IFR02, Paris, France
| | - P Bénit
- Hôpital Robert Debré, Paris, France
- Université Paris 7, Faculté de médecine Denis Diderot, IFR02, Paris, France
| | - H Ogier de Baulny
- Centre de référence Maladies Métaboliques, Hôpital Robert Debré, APHP, Paris, France
| | - P Rustin
- Hôpital Robert Debré, Paris, France.
- Université Paris 7, Faculté de médecine Denis Diderot, IFR02, Paris, France.
- INSERM U676, Bâtiment Ecran, Hôpital Robert Debré, 48, boulevard Sérurier, 75019, Paris, France.
| |
Collapse
|
166
|
Calmels N, Schmucker S, Wattenhofer-Donzé M, Martelli A, Vaucamps N, Reutenauer L, Messaddeq N, Bouton C, Koenig M, Puccio H. The first cellular models based on frataxin missense mutations that reproduce spontaneously the defects associated with Friedreich ataxia. PLoS One 2009; 4:e6379. [PMID: 19629184 PMCID: PMC2710521 DOI: 10.1371/journal.pone.0006379] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 06/25/2009] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Friedreich ataxia (FRDA), the most common form of recessive ataxia, is due to reduced levels of frataxin, a highly conserved mitochondrial iron-chaperone involved in iron-sulfur cluster (ISC) biogenesis. Most patients are homozygous for a (GAA)(n) expansion within the first intron of the frataxin gene. A few patients, either with typical or atypical clinical presentation, are compound heterozygous for the GAA expansion and a micromutation. METHODOLOGY We have developed a new strategy to generate murine cellular models for FRDA: cell lines carrying a frataxin conditional allele were used in combination with an EGFP-Cre recombinase to create murine cellular models depleted for endogenous frataxin and expressing missense-mutated human frataxin. We showed that complete absence of murine frataxin in fibroblasts inhibits cell division and leads to cell death. This lethal phenotype was rescued through transgenic expression of human wild type as well as mutant (hFXN(G130V) and hFXN(I154F)) frataxin. Interestingly, cells expressing the mutated frataxin presented a FRDA-like biochemical phenotype. Though both mutations affected mitochondrial ISC enzymes activities and mitochondria ultrastructure, the hFXN(I154F) mutant presented a more severe phenotype with affected cytosolic and nuclear ISC enzyme activities, mitochondrial iron accumulation and an increased sensitivity to oxidative stress. The differential phenotype correlates with disease severity observed in FRDA patients. CONCLUSIONS These new cellular models, which are the first to spontaneously reproduce all the biochemical phenotypes associated with FRDA, are important tools to gain new insights into the in vivo consequences of pathological missense mutations as well as for large-scale pharmacological screening aimed at compensating frataxin deficiency.
Collapse
Affiliation(s)
- Nadège Calmels
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Collège de France, Chaire de génétique humaine, Illkirch, France
| | - Stéphane Schmucker
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Collège de France, Chaire de génétique humaine, Illkirch, France
| | - Marie Wattenhofer-Donzé
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Collège de France, Chaire de génétique humaine, Illkirch, France
| | - Alain Martelli
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Collège de France, Chaire de génétique humaine, Illkirch, France
| | - Nadège Vaucamps
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
| | - Laurence Reutenauer
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- CNRS, UMR7104, Illkirch, France
| | - Nadia Messaddeq
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U596, Illkirch, France
| | - Cécile Bouton
- Institut de Chimie des Substance Naturelles, CNRS, Gif-sur-Yvette, France
| | - Michel Koenig
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U596, Illkirch, France
- CNRS, UMR7104, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Collège de France, Chaire de génétique humaine, Illkirch, France
| | - Hélène Puccio
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U596, Illkirch, France
- CNRS, UMR7104, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Collège de France, Chaire de génétique humaine, Illkirch, France
| |
Collapse
|