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Yerbury JJ, Farrawell NE, McAlary L. Proteome Homeostasis Dysfunction: A Unifying Principle in ALS Pathogenesis. Trends Neurosci 2020; 43:274-284. [PMID: 32353332 DOI: 10.1016/j.tins.2020.03.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/18/2020] [Accepted: 03/01/2020] [Indexed: 02/08/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease but currently has no effective treatment. Growing evidence suggests that proteome homeostasis underlies ALS pathogenesis. Protein production, trafficking, and degradation all shape the proteome. We present a hypothesis that proposes all genetic lesions associated with ALS (including in mRNA-binding proteins) cause widespread imbalance to an already metastable proteome. The impact of such dysfunction is felt across the entire proteome and is not restricted to a small subset of proteins. Proteome imbalance may cause functional defects, such as excitability alterations, and eventually cell death. While this idea is a unifying principle for all of ALS, we propose that stratification will appear that might dictate the efficacy of therapeutics based on the proteostasis network.
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Affiliation(s)
- Justin J Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia; Molecular Horizons and School of Chemistry and Molecular Biosciences, University of Wollongong, Wollongong, NSW 2522, Australia.
| | - Natalie E Farrawell
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia; Molecular Horizons and School of Chemistry and Molecular Biosciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Luke McAlary
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia; Molecular Horizons and School of Chemistry and Molecular Biosciences, University of Wollongong, Wollongong, NSW 2522, Australia
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2
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Farrawell NE, Lambert-Smith I, Mitchell K, McKenna J, McAlary L, Ciryam P, Vine KL, Saunders DN, Yerbury JJ. SOD1 A4V aggregation alters ubiquitin homeostasis in a cell model of ALS. J Cell Sci 2018; 131:jcs.209122. [PMID: 29748379 DOI: 10.1242/jcs.209122] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 05/01/2018] [Indexed: 12/11/2022] Open
Abstract
A hallmark of amyotrophic lateral sclerosis (ALS) pathology is the accumulation of ubiquitylated protein inclusions within motor neurons. Recent studies suggest the sequestration of ubiquitin (Ub) into inclusions reduces the availability of free Ub, which is essential for cellular function and survival. However, the dynamics of the Ub landscape in ALS have not yet been described. Here, we show that Ub homeostasis is altered in a cell model of ALS induced by expressing mutant SOD1 (SOD1A4V). By monitoring the distribution of Ub in cells expressing SOD1A4V, we show that Ub is present at the earliest stages of SOD1A4V aggregation, and that cells containing SOD1A4V aggregates have greater ubiquitin-proteasome system (UPS) dysfunction. Furthermore, SOD1A4V aggregation is associated with the redistribution of Ub and depletion of the free Ub pool. Ubiquitomics analysis indicates that expression of SOD1A4V is associated with a shift of Ub to a pool of supersaturated proteins, including those associated with oxidative phosphorylation and metabolism, corresponding with altered mitochondrial morphology and function. Taken together, these results suggest that misfolded SOD1 contributes to UPS dysfunction and that Ub homeostasis is an important target for monitoring pathological changes in ALS.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Natalie E Farrawell
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia 2522.,Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, NSW, Australia 2522
| | - Isabella Lambert-Smith
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia 2522.,Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, NSW, Australia 2522
| | - Kristen Mitchell
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia 2522.,Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, NSW, Australia 2522
| | - Jessie McKenna
- School of Medical Sciences, Faculty of Medicine, UNSW Australia 2052
| | - Luke McAlary
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia 2522.,Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, NSW, Australia 2522.,Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 2B5
| | - Prajwal Ciryam
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.,Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208-3500, USA.,Department of Neurology, Columbia University College of Physicians & Surgeons, New York, NY 10032-3784, USA
| | - Kara L Vine
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia 2522.,Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, NSW, Australia 2522
| | - Darren N Saunders
- School of Medical Sciences, Faculty of Medicine, UNSW Australia 2052
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia 2522 .,Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, NSW, Australia 2522
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3
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Hubbs AF, Fluharty KL, Edwards RJ, Barnabei JL, Grantham JT, Palmer SM, Kelly F, Sargent LM, Reynolds SH, Mercer RR, Goravanahally MP, Kashon ML, Honaker JC, Jackson MC, Cumpston AM, Goldsmith WT, McKinney W, Fedan JS, Battelli LA, Munro T, Bucklew-Moyers W, McKinstry K, Schwegler-Berry D, Friend S, Knepp AK, Smith SL, Sriram K. Accumulation of Ubiquitin and Sequestosome-1 Implicate Protein Damage in Diacetyl-Induced Cytotoxicity. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2887-2908. [PMID: 27643531 PMCID: PMC5222965 DOI: 10.1016/j.ajpath.2016.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 07/09/2016] [Accepted: 07/21/2016] [Indexed: 01/12/2023]
Abstract
Inhaled diacetyl vapors are associated with flavorings-related lung disease, a potentially fatal airway disease. The reactive α-dicarbonyl group in diacetyl causes protein damage in vitro. Dicarbonyl/l-xylulose reductase (DCXR) metabolizes diacetyl into acetoin, which lacks this α-dicarbonyl group. To investigate the hypothesis that flavorings-related lung disease is caused by in vivo protein damage, we correlated diacetyl-induced airway damage in mice with immunofluorescence for markers of protein turnover and autophagy. Western immunoblots identified shifts in ubiquitin pools. Diacetyl inhalation caused dose-dependent increases in bronchial epithelial cells with puncta of both total ubiquitin and K63-ubiquitin, central mediators of protein turnover. This response was greater in Dcxr-knockout mice than in wild-type controls inhaling 200 ppm diacetyl, further implicating the α-dicarbonyl group in protein damage. Western immunoblots demonstrated decreased free ubiquitin in airway-enriched fractions. Transmission electron microscopy and colocalization of ubiquitin-positive puncta with lysosomal-associated membrane proteins 1 and 2 and with the multifunctional scaffolding protein sequestosome-1 (SQSTM1/p62) confirmed autophagy. Surprisingly, immunoreactive SQSTM1 also accumulated in the olfactory bulb of the brain. Olfactory bulb SQSTM1 often congregated in activated microglial cells that also contained olfactory marker protein, indicating neuronophagia within the olfactory bulb. This suggests the possibility that SQSTM1 or damaged proteins may be transported from the nose to the brain. Together, these findings strongly implicate widespread protein damage in the etiology of flavorings-related lung disease.
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Affiliation(s)
- Ann F Hubbs
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia.
| | - Kara L Fluharty
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Rebekah J Edwards
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Jamie L Barnabei
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; College of Veterinary Medicine, University of Georgia, Athens, Georgia
| | - John T Grantham
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; School of Medicine, West Virginia University, Morgantown, West Virginia
| | - Scott M Palmer
- Duke University School of Medicine, Durham, North Carolina
| | - Francine Kelly
- Duke University School of Medicine, Durham, North Carolina
| | - Linda M Sargent
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Steven H Reynolds
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Robert R Mercer
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Madhusudan P Goravanahally
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Centers for Neuroscience, West Virginia University, Morgantown, West Virginia
| | - Michael L Kashon
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - John C Honaker
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Mark C Jackson
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Amy M Cumpston
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - William T Goldsmith
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Walter McKinney
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Jeffrey S Fedan
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Lori A Battelli
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Tiffany Munro
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Winnie Bucklew-Moyers
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Kimberly McKinstry
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Diane Schwegler-Berry
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Sherri Friend
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Alycia K Knepp
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Samantha L Smith
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Krishnan Sriram
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
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Yerbury JJ, Ooi L, Dillin A, Saunders DN, Hatters DM, Beart PM, Cashman NR, Wilson MR, Ecroyd H. Walking the tightrope: proteostasis and neurodegenerative disease. J Neurochem 2016; 137:489-505. [DOI: 10.1111/jnc.13575] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Justin J. Yerbury
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Lezanne Ooi
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Andrew Dillin
- Department of Molecular and Cell Biology; Li Ka Shing Center for Biomedical and Health Sciences; The University of California; California USA
- Howard Hughes Medical Institute; The University of California; Berkeley California USA
| | - Darren N. Saunders
- School of Medical Sciences; Faculty of Medicine; University of New South Wales; Randwick New South Wales Australia
- The Kinghorn Cancer Centre; Garvan Institute of Medical Research; Darlinghurst New South Wales Australia
| | - Danny M. Hatters
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute; University of Melbourne; Parkville Victoria Australia
| | - Philip M. Beart
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria Australia
| | - Neil R. Cashman
- Department of Medicine (Neurology); University of British Columbia and Vancouver Coastal Health Research Institute; Brain Research Centre; University of British Columbia; Vancouver British Columbia Canada
| | - Mark R. Wilson
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Heath Ecroyd
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
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5
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Marquez-Lona EM, Tan Z, Schreiber SS. Nucleolar stress characterized by downregulation of nucleophosmin: a novel cause of neuronal degeneration. Biochem Biophys Res Commun 2011; 417:514-20. [PMID: 22166220 DOI: 10.1016/j.bbrc.2011.11.152] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 11/30/2011] [Indexed: 11/30/2022]
Abstract
Nucleophosmin (NPM) is a multifunctional nucleolar protein that has been linked with nucleolar stress. In non-neuronal cell lines, NPM may enhance or inhibit the activity of tumor suppressor p53, a major apoptotic protein. The relationship between NPM and p53 in the central nervous system (CNS) remains unknown. Here, we assessed the role of NPM in the CNS using a model of seizure-induced neurodegeneration. We show that NPM overexpression is neuroprotective against kainic acid-induced excitotoxicity, and that downregulation of NPM is pro-apoptotic in a p53-independent manner. These results suggest a key role for NPM in promoting neuronal survival and a novel mechanism of neuronal degeneration triggered by nucleolar stress.
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6
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Erratum: Neural protection by naturopathic compounds-an example of tetramethylpyrazine from retina to brain. J Ocul Biol Dis Infor 2009; 2:137-144. [PMID: 20046848 PMCID: PMC2798986 DOI: 10.1007/s12177-009-9033-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Given the advantages of being stable in the ambient environment, being permeable to the blood-brain and/or blood-eye barriers and being convenient for administration, naturopathic compounds have growingly become promising therapeutic candidates for neural protection. Extracted from one of the most common Chinese herbal medicines, tetramethylpyrazine (TMP), also designated as ligustrazine, has been suggested to be neuroprotective in the central nervous system as well as the peripheral nerve network. Although the detailed molecular mechanisms of its efficacy for neural protection are understood limitedly, accumulating evidence suggests that antioxidative stress, antagonism for calcium, and suppression of pro-inflammatory factors contribute significantly to its neuroprotection. In animal studies, systemic administration of TMP (subcutaneous injection, 50 mg/kg) significantly blocked neuronal degeneration in hippocampus as well as the other vulnerable regions in brains of Sprague-Dawley rats following kainate-induced prolonged seizures. Results from us and others also demonstrated potent neuroprotective efficacy of TMP for retinal cells and robust benefits for brain in Alzheimer's disease or other brain injury. These results suggest a promising prospect for TMP to be used as a treatment of specific neurodegenerative diseases. Given the assessment of the distribution, metabolism, excretion, and toxicity information that is already available on most neuroprotective naturopathic compounds such as TMP, preclinical data to justify bringing such therapeutic compounds to clinical trials in humans is feasible.[This corrects the article on p. in vol. .].
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7
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Tan Z. Neural protection by naturopathic compounds-an example of tetramethylpyrazine from retina to brain. J Ocul Biol Dis Infor 2009; 2:57-64. [PMID: 19672463 PMCID: PMC2723671 DOI: 10.1007/s12177-009-9024-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 06/02/2009] [Indexed: 01/06/2023] Open
Abstract
Given the advantages of being stable in the ambient environment, being permeable to the blood–brain and/or blood–eye barriers and being convenient for administration, naturopathic compounds have growingly become promising therapeutic candidates for neural protection. Extracted from one of the most common Chinese herbal medicines, tetramethylpyrazine (TMP), also designated as ligustrazine, has been suggested to be neuroprotective in the central nervous system as well as the peripheral nerve network. Although the detailed molecular mechanisms of its efficacy for neural protection are understood limitedly, accumulating evidence suggests that antioxidative stress, antagonism for calcium, and suppression of pro-inflammatory factors contribute significantly to its neuroprotection. In animal studies, systemic administration of TMP (subcutaneous injection, 50 mg/kg) significantly blocked neuronal degeneration in hippocampus as well as the other vulnerable regions in brains of Sprague–Dawley rats following kainate-induced prolonged seizures. Results from us and others also demonstrated potent neuroprotective efficacy of TMP for retinal cells and robust benefits for brain in Alzheimer’s disease or other brain injury. These results suggest a promising prospect for TMP to be used as a treatment of specific neurodegenerative diseases. Given the assessment of the distribution, metabolism, excretion, and toxicity information that is already available on most neuroprotective naturopathic compounds such as TMP, it would not take much preclinical data to justify bringing such therapeutic compounds to clinical trials in humans.
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Affiliation(s)
- Zhiqun Tan
- Department of Neurology, University of California Irvine School of Medicine, ZOT 4275, 100 Irvine Hall, Irvine, CA 92697 USA
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8
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Sass MB, Lorenz AN, Green RL, Coleman RA. A pragmatic approach to biochemical systems theory applied to an α-synuclein-based model of Parkinson's disease. J Neurosci Methods 2009; 178:366-77. [DOI: 10.1016/j.jneumeth.2008.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 11/24/2008] [Accepted: 12/11/2008] [Indexed: 10/21/2022]
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9
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Yang Z, Zhang Q, Ge J, Tan Z. Protective effects of tetramethylpyrazine on rat retinal cell cultures. Neurochem Int 2007; 52:1176-87. [PMID: 18261827 DOI: 10.1016/j.neuint.2007.12.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 12/07/2007] [Accepted: 12/16/2007] [Indexed: 01/10/2023]
Abstract
The retinal degeneration characterized with death of retinal ganglion cells is a pathological hallmark and the final common pathway of various optic neuropathies. Thus, there is an urgent need for identifying potential therapeutic compounds for retinal protection. Tetramethylpyrazine has been suggested to be neuroprotective for central neurons by acting as an antioxidant and a calcium antagonist. In this study, we tested the effects of tetramethylpyrazine on the viability of both neuronal and non-neuronal cells in mixed rat retinal cell cultures during a long-term cultivation or following hydrogen peroxide treatments. Cellular and biochemical analyses demonstrated that 50 microM tetramethylpyrazine significantly preserved neuronal morphology and survival in retinal cell cultures following 4-week in vitro cultivation as well as lethal exposures to hydrogen peroxide (10 microM or 50 microM for 24h). Hydrogen peroxide treatments induced remarkable increases in lipid peroxidation and mitochondrial reactive oxygen species (ROS) generation paralleled by the loss of mitochondrial membrane potential, microtubule-associated protein-2 (MAP-2) in neuronal soma and rattin peptide in cultured cells. Addition of tetramethylpyrazine in the cultures efficiently attenuated the signs of oxidative stress and retained abundance of MAP-2 and rattin in association with cell survival. In addition, siRNA-mediated downregulation of MAP-2 or rattin significantly increased the vulnerability of retinal neurons or the number of degenerating cells in the cultures, respectively, whereas exogenous humanin peptide, an analog of rattin, promoted cell survival in cultures under hydrogen peroxide attacks. These results suggest that tetramethylpyrazine protect retinal cells through multiple pathways and might be a potential therapeutic candidate for retinal protection in certain optic neuropathies.
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Affiliation(s)
- Zhikuan Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou 510060, China
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10
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Seki T, Takahashi H, Adachi N, Abe N, Shimahara T, Saito N, Sakai N. Aggregate formation of mutant protein kinase C gamma found in spinocerebellar ataxia type 14 impairs ubiquitin-proteasome system and induces endoplasmic reticulum stress. Eur J Neurosci 2007; 26:3126-40. [DOI: 10.1111/j.1460-9568.2007.05933.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Yao X, Liu J, McCabe JT. Ubiquitin and ubiquitin-conjugated protein expression in the rat cerebral cortex and hippocampus following traumatic brain injury (TBI). Brain Res 2007; 1182:116-22. [PMID: 17936732 DOI: 10.1016/j.brainres.2007.08.076] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 08/29/2007] [Accepted: 08/30/2007] [Indexed: 01/25/2023]
Abstract
Regulation of protein turnover is essential to the survival of eukaryotic cells. This important cellular process is partly regulated by the ubiquitin-proteasome system through posttranslational modification by the conjugation of ubiquitin chains to proteins targeted for degradation by proteasomes. The present study examined ubiquitin mRNA and protein expression in the CNS of rats that sustained traumatic brain injury (TBI). Quantitative real-time polymerase chain reaction results indicated that mRNA levels of ubA52, ubB and ubC in the ipsilateral cerebral cortex were significantly decreased on Day 1 post-TBI, that ubC mRNA levels also were significantly lower than control on Day 3 post-TBI, but that by Day 7 post-TBI, ubA52, ubB and ubC mRNA levels had all returned to control levels. In the ipsilateral hippocampus, ubA52 mRNA levels were significantly lower on Days 1-7 post-TBI, while ubB and ubC mRNA levels were less only on Day 1 post-TBI. Western blotting found that free ubiquitin protein levels were significantly reduced in both ipsilateral cerebral cortex and hippocampus on Days 1-7 post-TBI, while there was markedly increased ubiquitin-conjugated protein in ipsilateral cerebral cortex on Day 7 and in hippocampus on Days 3-7 post-TBI. Our study suggests that altered ubiquitin system function in the CNS contributes to the pathological outcomes of TBI.
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Affiliation(s)
- Xianglan Yao
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799, USA
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12
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Tan Z, Sun X, Hou FS, Oh HW, Hilgenberg LGW, Hol EM, van Leeuwen FW, Smith MA, O'Dowd DK, Schreiber SS. Mutant ubiquitin found in Alzheimer's disease causes neuritic beading of mitochondria in association with neuronal degeneration. Cell Death Differ 2007; 14:1721-32. [PMID: 17571083 PMCID: PMC3258508 DOI: 10.1038/sj.cdd.4402180] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A dinucleotide deletion in human ubiquitin (Ub) B messenger RNA leads to formation of polyubiquitin (UbB)+1, which has been implicated in neuronal cell death in Alzheimer's and other neurodegenerative diseases. Previous studies demonstrate that UbB+1 protein causes proteasome dysfunction. However, the molecular mechanism of UbB+1-mediated neuronal degeneration remains unknown. We now report that UbB+1 causes neuritic beading, impairment of mitochondrial movements, mitochondrial stress and neuronal degeneration in primary neurons. Transfection of UbB+1 induced a buildup of mitochondria in neurites and dysregulation of mitochondrial motor proteins, in particular, through detachment of P74, the dynein intermediate chain, from mitochondria and decreased mitochondria-microtubule interactions. Altered distribution of mitochondria was associated with activation of both the mitochondrial stress and p53 cell death pathways. These results support the hypothesis that neuritic clogging of mitochondria by UbB+1 triggers a cascade of events characterized by local activation of mitochondrial stress followed by global cell death. Furthermore, UbB+1 small interfering RNA efficiently blocked expression of UbB+1 protein, attenuated neuritic beading and preserved cellular morphology, suggesting a potential neuroprotective strategy for certain neurodegenerative disorders.
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Affiliation(s)
- Z Tan
- Department of Neurology, University of California, Irvine, CA 92697, USA.
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13
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Shu KX, Li B, Wu LX. The p53 network: p53 and its downstream genes. Colloids Surf B Biointerfaces 2007; 55:10-8. [PMID: 17188467 DOI: 10.1016/j.colsurfb.2006.11.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 10/17/2006] [Accepted: 11/03/2006] [Indexed: 12/13/2022]
Abstract
The tumor-suppressor gene p53 and its downstream genes consist of a complicated gene network. p53 is a key molecular node in the network, which is activated in response to several cellular signals resulting in the maintenance of genetic stability. Several cellular signals may activate the p53 network. When the expression of P53 is elevated, P53-MDM2 module and the ubiquitin system can accurately regulate the expression level of P53. P53 can bind to specific DNA sequence, activate its downstream genes expression, and control cell-cycle arrest, DNA repair, and apoptosis. Elucidating the function of p53 gene network will help understand the interaction mechanisms of p53 and its downstream genes.
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Affiliation(s)
- Kun-Xian Shu
- College of Bioinformation, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
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14
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Demasi MAA, Montor WR, Ferreira GB, Pimenta DC, Labriola L, Sogayar MC. Differential proteomic analysis of the anti-proliferative effect of glucocorticoid hormones in ST1 rat glioma cells. J Steroid Biochem Mol Biol 2007; 103:137-48. [PMID: 17127050 DOI: 10.1016/j.jsbmb.2006.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Accepted: 08/17/2006] [Indexed: 02/02/2023]
Abstract
Glucocorticoid hormones (GCs) exert a potent anti-proliferative activity on several cell types. The classic molecular mechanism of GCs involves modulation of the activity of the glucocorticoids receptor, a transcriptional regulator. However, the anti-proliferative effect of GCs may also involve modulation of processes such as translation, subcellular localization and post-translational modifications, which are not reflected at the mRNA level. To investigate these potential effects of GCs, we employed the proteomic approach (two-dimensional electrophoresis and mass spectrometry) and the ST1 cells, obtained from the C6 rat glioma cell line, as a model. GC treatment leads ST1 cells to a complete transformed-to-normal phenotypic reversion and loss of their tumorigenic potential. By comparing sets of 2D nuclear protein profiles of ST1 cells treated (or not) with hydrocortisone (Hy), 13 polypeptides displaying >or=two-fold difference in abundance upon Hy treatment were found. Five of these polypeptides were identified by peptide mass fingerprinting, including Annexin 2 (ANX2), hnRNP A3 and Ubiquitin. Evidence obtained by Western blot analysis indicates that ANX2 is present in the nucleus and has its subcellular localization modulated by GC-treatment of ST1 cells. Our findings indicate complementary mechanisms contributing to the regulation of gene expression associated with ST1 cells' response to GCs.
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Affiliation(s)
- Marcos A A Demasi
- Instituto de Química, Universidade de São Paulo, 05508-900 SP, São Paulo, Brazil
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15
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Li J, Bai Y, Ianakova E, Grandis M, Uchwat F, Trostinskaia A, Krajewski KM, Garbern J, Kupsky WJ, Shy ME. Major myelin protein gene (P0) mutation causes a novel form of axonal degeneration. J Comp Neurol 2007; 498:252-65. [PMID: 16856127 DOI: 10.1002/cne.21051] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mutations in the major peripheral nervous system (PNS) myelin protein, myelin protein zero (MPZ), cause Charcot-Marie-Tooth Disease type 1B (CMT1B), typically thought of as a demyelinating peripheral neuropathy. Certain MPZ mutations, however, cause adult onset neuropathy with minimal demyelination but pronounced axonal degeneration. Mechanism(s) for this phenotype are unknown. We performed an autopsy of a 73-year-old woman with a late-onset neuropathy caused by an H10P MPZ mutation whose nerve conduction studies suggested severe axonal loss but no demyelination. The autopsy demonstrated axonal loss and reorganization of the molecular architecture of the axolemma. Segmental demyelination was negligible. In addition, we identified focal nerve enlargements containing MPZ and ubiquitin either in the inner myelin intralaminar and/or periaxonal space that separates axons from myelinating Schwann cells. Taken together, these data confirmed that a mutation in MPZ can cause axonal neuropathy, in the absence of segmental demyelination, thus uncoupling the two pathological processes. More important, it also provided potential molecular mechanisms as to how the axonal degeneration occurred: either by disruption of glial-axon interaction by protein aggregates or by alterations in the molecular architecture of internodes and paranodes. This report represents the first study in which the molecular basis of axonal degeneration in the late-onset CMT1B has been explored in human tissue.
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Affiliation(s)
- Jun Li
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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16
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Tangpong J, Cole MP, Sultana R, Joshi G, Estus S, Vore M, St Clair W, Ratanachaiyavong S, St Clair DK, Butterfield DA. Adriamycin-induced, TNF-α-mediated central nervous system toxicity. Neurobiol Dis 2006; 23:127-39. [PMID: 16697651 DOI: 10.1016/j.nbd.2006.02.013] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2005] [Revised: 02/08/2006] [Accepted: 02/15/2006] [Indexed: 11/25/2022] Open
Abstract
The clinical effectiveness of adriamycin (ADR), a potent chemotherapeutic, is known to be limited by severe cardiotoxic side effects. However, the effect of ADR on brain tissue is not well understood. It is generally thought that ADR is not toxic to the brain because ADR does not pass the blood-brain barrier. The present study demonstrates that ADR autofluorescence was detected only in areas of the brain located outside the blood-brain barrier, but a strong tumor necrosis factor (TNF) alpha immunoreactivity was detected in the cortex and hippocampus of ADR-treated mice. Systemic injection of ADR led to a decline in brain mitochondrial respiration via complex I substrate shortly after ADR treatment (P < 0.05). Cytochrome c release, increased caspase 3 activity, and TUNEL-positive cell death all were suggestive of apoptosis in brain following systemic ADR treatment. The levels of the known pro-apoptotic proteins, p53 and Bax, were increased in brain mitochondria at 3 h following ADR treatment and declined by 48 h. In contrast, the anti-apoptotic protein, Bcl-xL, was increased later at 6 h post-ADR treatment and was sustained throughout 72 h. Furthermore, p53 migrated to mitochondria and interacted with Bcl-xL, supporting the hypothesis that mitochondria are targets of ADR-induced CNS injury. Neutralizing antibodies against circulating TNF completely abolished both the increased TNF in the brain and the observed mitochondrial injury in brain tissues. These results are consistent with the notion that TNF is an important mediator by which ADR induces central nervous system (CNS) injury. This study, the first to provide direct biochemical evidence of ADR toxicity to the brain, revealed novel mechanisms of ADR-induced CNS injury and suggests a potential therapeutic intervention against circulating TNF-induced CNS effects.
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Affiliation(s)
- Jitbanjong Tangpong
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA
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17
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Hanna J, Leggett DS, Finley D. Ubiquitin depletion as a key mediator of toxicity by translational inhibitors. Mol Cell Biol 2004; 23:9251-61. [PMID: 14645527 PMCID: PMC309641 DOI: 10.1128/mcb.23.24.9251-9261.2003] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cycloheximide acts at the large subunit of the ribosome to inhibit translation. Here we report that ubiquitin levels are critical for the survival of Saccharomyces cerevisiae cells in the presence of cycloheximide: ubiquitin overexpression confers resistance to cycloheximide, while a reduced ubiquitin level confers sensitivity. Consistent with these findings, ubiquitin is unstable in yeast (t(1/2) = 2 h) and is rapidly depleted upon cycloheximide treatment. Cycloheximide does not noticeably enhance ubiquitin turnover, but serves principally to block ubiquitin synthesis. Cycloheximide also induces UBI4, the polyubiquitin gene. The cycloheximide-resistant phenotype of ubiquitin overexpressors is also characteristic of partial-loss-of-function proteasome mutants. Ubiquitin is stabilized in these mutants, which may account for their cycloheximide resistance. Previous studies have reported that ubiquitin is destabilized in the absence of Ubp6, a proteasome-associated deubiquitinating enzyme, and that ubp6 mutants are hypersensitive to cycloheximide. Consistent with the model that cycloheximide-treated cells are ubiquitin deficient, the cycloheximide sensitivity of ubp6 mutants can be rescued either by ubiquitin overexpression or by mutations in proteasome subunit genes. These results also show that ubiquitin wasting in ubp6 mutants is proteasome mediated. Ubiquitin overexpression rescued cells from additional translational inhibitors such as anisomycin and hygromycin B, suggesting that ubiquitin depletion may constitute a widespread mechanism for the toxicity of translational inhibitors.
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Affiliation(s)
- John Hanna
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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18
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Abstract
The p53 tumor suppressor gene plays an important role in preventing cancer development, by arresting or killing potential tumor cells. Mutations within the p53 gene, leading to the loss of p53 activity, are found in about half of all human cancers, while many of the tumors that retain wild type p53 carry mutations in the pathways that allow full activation of p53. In either case, the result is a defect in the ability to induce a p53 response in cells undergoing oncogenic stress. Significant advances have been made recently in our understanding of the molecular pathways through which p53 activity is regulated, bringing with them fresh possibilities for the design of cancer therapies based on reactivation of the p53 response.
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Affiliation(s)
- Karen H Vousden
- Regulation of Cell Growth Laboratory, National Cancer Institute at Frederick, Frederick, MD 21702, USA.
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19
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Tan Z, Sankar R, Tu W, Shin D, Liu H, Wasterlain CG, Schreiber SS. Immunohistochemical study of p53-associated proteins in rat brain following lithium-pilocarpine status epilepticus. Brain Res 2002; 929:129-38. [PMID: 11852039 DOI: 10.1016/s0006-8993(01)03360-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Activation of the p53-stress response pathway has been implicated in excitotoxic neuronal cell death. Recent studies have demonstrated an age-dependent induction of both p53 mRNA and protein in the rat brain following lithium-pilocarpine-mediated status epilepticus (LPSE). We investigated whether other proteins that have been shown to participate in the p53 cascade are induced by LPSE. We used immunohistochemistry to examine the expression of Mdm2, Bax, CD95/Fas/APO-1, ATM, Ref-1 and ubiquitin. A significant increase in nuclear Mdm2 immunoreactivity, which colocalized with p53, was observed in cells within hippocampal pyramidal cell layers, dentate gyrus, piriform cortex, amygdala and thalamus. Dual immunofluorescence microscopy revealed a reduction in free ubiquitin expression in cells with p53 and Mdm2 accumulation. Increased immunoreactivity for CD95/Fas/APO-1 and Bax was also detected in the same p53-positive cells. Moreover, expression of Ref-1 and ATM, which are involved in the response to oxidative stress-induced DNA damage and regulation of p53 function, were increased. Colocalization of Ref-1 and p53 suggests that Ref-1 might activate p53 function in LPSE-induced neurodegeneration. In contrast, ATM immunoreactivity was predominantly cytoplasmic suggesting that ATM may not directly modulate p53 activity in injured neurons. These results extend our previous observations with regard to activation and stabilization of p53 in injured central nervous system neurons. The data indicate that p53 induction following LPSE may activate downstream pro-apoptotic genes leading to neurodegeneration.
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Affiliation(s)
- Zhiqun Tan
- Department of Neurology, USC Keck School of Medicine, Los Angeles, CA 90033, USA
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20
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Tan Z, Sankar R, Shin D, Sun N, Liu H, Wasterlain CG, Schreiber SS. Differential induction of p53 in immature and adult rat brain following lithium-pilocarpine status epilepticus. Brain Res 2002; 928:187-93. [PMID: 11844486 DOI: 10.1016/s0006-8993(01)03359-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Activation of the tumor suppressor gene, p53, has been strongly implicated in selective neuronal cell death. This study investigated p53 expression in the immature and adult rat brain following status epilepticus induced by the administration of lithium-pilocarpine (LPSE). Both p53 mRNA and protein were examined in relation to neuronal degeneration using in situ hybridization and immunohistochemistry, respectively. Injured cells with eosinophilic cytoplasm with increased p53 mRNA were observed in hippocampal subfields, piriform cortex, amygdala and thalamus. p53 mRNA levels reached a peak by 8 h and returned to baseline by 24 h after the onset of LPSE. The magnitude of p53 mRNA induction was greatest in 21-day-old rats. In contrast to the cellular expression pattern of p53 mRNA, immunohistochemistry demonstrated that p53 protein was increased in all of the eosinophilic cells. Further, double-labeling studies revealed that p53 protein was elevated in neurons that were degenerating. This was supported by colocalization of activated caspase 3 in some cells with damaged DNA. These results provide additional evidence for a critical role for the p53 pathway in excitotoxic neuronal cell death due to status epilepticus.
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Affiliation(s)
- Zhiqun Tan
- Department of Neurology, Keck School of Medicine, University of Southern California, 1333 San Pablo Street MCH 142, Los Angeles, CA 90033, USA
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