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García‐Gomis D, López J, Calderón A, Andrés M, Ponte I, Roque A. Proteasome-dependent degradation of histone H1 subtypes is mediated by its C-terminal domain. Protein Sci 2024; 33:e4970. [PMID: 38591484 PMCID: PMC11002908 DOI: 10.1002/pro.4970] [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: 09/27/2023] [Revised: 02/29/2024] [Accepted: 03/10/2024] [Indexed: 04/10/2024]
Abstract
Histone H1 is involved in chromatin compaction and dynamics. In human cells, the H1 complement is formed by different amounts of somatic H1 subtypes, H1.0-H1.5 and H1X. The amount of each variant depends on the cell type, the cell cycle phase, and the time of development and can be altered in disease. However, the mechanisms regulating H1 protein levels have not been described. We have analyzed the contribution of the proteasome to the degradation of H1 subtypes in human cells using two different inhibitors: MG132 and bortezomib. H1 subtypes accumulate upon treatment with both drugs, indicating that the proteasome is involved in the regulation of H1 protein levels. Proteasome inhibition caused a global increase in cytoplasmatic H1, with slight changes in the composition of H1 bound to chromatin and chromatin accessibility and no alterations in the nucleosome repeat length. The analysis of the proteasome degradation pathway showed that H1 degradation is ubiquitin-independent. The whole protein and its C-terminal domain can be degraded directly by the 20S proteasome in vitro. Partial depletion of PA28γ revealed that this regulatory subunit contributes to H1 degradation within the cell. Our study shows that histone H1 protein levels are under tight regulation to prevent its accumulation in the nucleus. We revealed a new regulatory mechanism for histone H1 degradation, where the C-terminal disordered domain is responsible for its targeting and degradation by the 20S proteasome, a process enhanced by the regulatory subunit PA28γ.
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Affiliation(s)
- D. García‐Gomis
- Biochemistry and Molecular Biology Department, Biosciences FacultyUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - J. López
- Biochemistry and Molecular Biology Department, Biosciences FacultyUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - A. Calderón
- Biochemistry and Molecular Biology Department, Biosciences FacultyUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - M. Andrés
- Biochemistry and Molecular Biology Department, Biosciences FacultyUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - I. Ponte
- Biochemistry and Molecular Biology Department, Biosciences FacultyUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - A. Roque
- Biochemistry and Molecular Biology Department, Biosciences FacultyUniversitat Autònoma de BarcelonaBarcelonaSpain
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2
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Shin EJ, Jeong JH, Hwang Y, Sharma N, Dang DK, Nguyen BT, Nah SY, Jang CG, Bing G, Nabeshima T, Kim HC. Methamphetamine-induced dopaminergic neurotoxicity as a model of Parkinson's disease. Arch Pharm Res 2021; 44:668-688. [PMID: 34286473 DOI: 10.1007/s12272-021-01341-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 07/06/2021] [Indexed: 12/01/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disease with a high prevalence, approximately 1 % in the elderly population. Numerous studies have demonstrated that methamphetamine (MA) intoxication caused the neurological deficits and nigrostriatal damage seen in Parkinsonian conditions, and subsequent rodent studies have found that neurotoxic binge administration of MA reproduced PD-like features, in terms of its symptomatology and pathology. Several anti-Parkinsonian medications have been shown to attenuate the motor impairments and dopaminergic damage induced by MA. In addition, it has been recognized that mitochondrial dysfunction, oxidative stress, pro-apoptosis, proteasomal/autophagic impairment, and neuroinflammation play important roles in inducing MA neurotoxicity. Importantly, MA neurotoxicity has been shown to share a common mechanism of dopaminergic toxicity with that of PD pathogenesis. This review describes the major findings on the neuropathological features and underlying neurotoxic mechanisms induced by MA and compares them with Parkinsonian pathogenesis. Taken together, it is suggested that neurotoxic binge-type administration of MA in rodents is a valid animal model for PD that may provide knowledge on the neuropathogenesis of PD.
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Affiliation(s)
- Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea
| | - Ji Hoon Jeong
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, College of Medicine, Chung-Ang University, 06974, Seoul, Republic of Korea
| | - Yeonggwang Hwang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea
| | - Naveen Sharma
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea.,Department of Global Innovative Drugs, Graduate School of Chung-Ang University, College of Medicine, Chung-Ang University, 06974, Seoul, Republic of Korea
| | - Duy-Khanh Dang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea.,Pharmacy Faculty, Can Tho University of Medicine and Pharmacy, 900000, Can Tho City, Vietnam
| | - Bao-Trong Nguyen
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory, Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, 05029, Seoul, Republic of Korea
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 16419, Suwon, Republic of Korea
| | - Guoying Bing
- Department of Neuroscience, College of Medicine, University of Kentucky, KY, 40536, Lexington, USA
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Graduate School of Health Science, Fujita Health University, 470-1192, Toyoake, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea. .,Neuropsychopharmacology & Toxicology Program, College of Pharmacy, Kangwon National University, 24341, Chunchon, Republic of Korea.
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Lee JE, Sim H, Yoo HM, Lee M, Baek A, Jeon YJ, Seo KS, Son MY, Yoon JS, Kim J. Neuroprotective Effects of Cryptotanshinone in a Direct Reprogramming Model of Parkinson's Disease. Molecules 2020; 25:molecules25163602. [PMID: 32784741 PMCID: PMC7463464 DOI: 10.3390/molecules25163602] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/02/2020] [Accepted: 08/05/2020] [Indexed: 12/17/2022] Open
Abstract
Parkinson’s disease (PD) is a well-known age-related neurodegenerative disease. Considering the vital importance of disease modeling based on reprogramming technology, we adopted direct reprogramming to human-induced neuronal progenitor cells (hiNPCs) for in vitro assessment of potential therapeutics. In this study, we investigated the neuroprotective effects of cryptotanshinone (CTN), which has been reported to have antioxidant properties, through PD patient-derived hiNPCs (PD-iNPCs) model with induced oxidative stress and cell death by the proteasome inhibitor MG132. A cytotoxicity assay showed that CTN possesses anti-apoptotic properties in PD-hiNPCs. CTN treatment significantly reduced cellular apoptosis through mitochondrial restoration, such as the reduction in mitochondrial reactive oxygen species and increments of mitochondrial membrane potential. These effects of CTN are mediated via the nuclear factor erythroid 2-related factor 2 (NRF2) pathway in PD-hiNPCs. Consequently, CTN could be a potential antioxidant reagent for preventing disease-related pathological phenotypes of PD.
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Affiliation(s)
- Joo-Eun Lee
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea; (J.-E.L.); (H.S.); (M.L.); (A.B.); (Y.-J.J.); (M.-Y.S.)
| | - Hyuna Sim
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea; (J.-E.L.); (H.S.); (M.L.); (A.B.); (Y.-J.J.); (M.-Y.S.)
- Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon 34113, Korea
| | - Hee Min Yoo
- Group for Biometrology, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Korea;
| | - Minhyung Lee
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea; (J.-E.L.); (H.S.); (M.L.); (A.B.); (Y.-J.J.); (M.-Y.S.)
| | - Aruem Baek
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea; (J.-E.L.); (H.S.); (M.L.); (A.B.); (Y.-J.J.); (M.-Y.S.)
| | - Young-Joo Jeon
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea; (J.-E.L.); (H.S.); (M.L.); (A.B.); (Y.-J.J.); (M.-Y.S.)
| | - Kang-Sik Seo
- Huen Co., Ltd., Gwanggyo Business Center 5F (#508), 156, Gwanggyo-ro, Yeongtong-gu, Suwon 16506, Korea;
| | - Mi-Young Son
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea; (J.-E.L.); (H.S.); (M.L.); (A.B.); (Y.-J.J.); (M.-Y.S.)
- Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon 34113, Korea
| | - Joo Seog Yoon
- Huen Co., Ltd., Gwanggyo Business Center 5F (#508), 156, Gwanggyo-ro, Yeongtong-gu, Suwon 16506, Korea;
- Correspondence: (J.S.Y.); (J.K.); Tel.: +82-31-8064-1622 (J.S.Y.); +82-42-860-4478 (J.K.)
| | - Janghwan Kim
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea; (J.-E.L.); (H.S.); (M.L.); (A.B.); (Y.-J.J.); (M.-Y.S.)
- Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon 34113, Korea
- Correspondence: (J.S.Y.); (J.K.); Tel.: +82-31-8064-1622 (J.S.Y.); +82-42-860-4478 (J.K.)
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Pathways of protein synthesis and degradation in PD pathogenesis. PROGRESS IN BRAIN RESEARCH 2020; 252:217-270. [PMID: 32247365 DOI: 10.1016/bs.pbr.2020.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Since the discovery of protein aggregates in the brains of individuals with Parkinson's disease (PD) in the early 20th century, the scientific community has been interested in the role of dysfunctional protein metabolism in PD etiology. Recent advances in the field have implicated defective protein handling underlying PD through genetic, in vitro, and in vivo studies incorporating many disease models alongside neuropathological evidence. Here, we discuss the existing body of research focused on understanding cellular pathways of protein synthesis and degradation, and how aberrations in either system could engender PD pathology with special attention to α-synuclein-related consequences. We consider transcription, translation, and post-translational modification to constitute protein synthesis, and protein degradation to encompass proteasome-, lysosome- and endoplasmic reticulum-dependent mechanisms. Novel findings connecting each of these steps in protein metabolism to development of PD indicate that deregulation of protein production and turnover remains an exciting area in PD research.
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5
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Akt Phosphorylates NQO1 and Triggers its Degradation, Abolishing Its Antioxidative Activities in Parkinson's Disease. J Neurosci 2019; 39:7291-7305. [PMID: 31358653 DOI: 10.1523/jneurosci.0625-19.2019] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/08/2019] [Accepted: 07/15/2019] [Indexed: 11/21/2022] Open
Abstract
The oxidative metabolism of dopamine and consequent oxidative stress are implicated in dopaminergic neuronal loss, mediating the pathogenesis of Parkinson's disease (PD). The inducible detoxifying antioxidative enzyme Quinone oxidoreductase (NQO1) (NAD(P)H: quinone oxidoreductase 1), neuroprotective to counteract reactive oxidative species, is most prominent in the active stage of the disease and virtually absent at the end stage of the disease. However, the molecular mechanism dictating NQO1 expression oscillation remains unclear. Here we show that Akt phosphorylates NQO1 at T128 residues and triggers its polyubiquitination and proteasomal degradation, abrogating its antioxidative effects in PD. Akt binds NQO1 in a phosphorylation-dependent manner. Interestingly, Akt, but not PINK1, provokes NQO1 phosphorylation and polyubiquitination with Parkin as an E3 ligase. Unphosphorylatable NQO1 mutant displays more robust neuroprotective activity than WT NQO1 in suppressing reactive oxidative species and against MPTP-induced dopaminergic cell death, rescuing the motor disorders in both α-synuclein transgenic transgenic male and female mice elicited by the neurotoxin. Thus, our findings demonstrate that blockade of Akt-mediated NQO1 degradation may ameliorate PD pathogenesis.SIGNIFICANCE STATEMENT Dopaminergic neurodegeneration in Parkinson's disease (PD) is associated with the imbalance of oxidative metabolism of dopamine. Quinone oxidoreductase (NQO1), a potent antioxidant system, its expression levels are prominently increased in the early and intermediate stages of PD and disappeared in the end-stage PD. The molecular modification behavior of NQO1 after it is upregulated by oxidative stress in the early stage of PD, however, remains unclear. This study shows that Akt binds and phosphorylates NQO1 at T128 residue and promotes its ubiquitination and degradation, and Parkin acts as an E3 ligase in this process, which affects the antioxidant capacity of NQO1. This finding provides a novel molecular mechanism for NQO1 oscillation in PD pathogenesis.
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Bentea E, Verbruggen L, Massie A. The Proteasome Inhibition Model of Parkinson's Disease. JOURNAL OF PARKINSONS DISEASE 2017; 7:31-63. [PMID: 27802243 PMCID: PMC5302045 DOI: 10.3233/jpd-160921] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The pathological hallmarks of Parkinson's disease are the progressive loss of nigral dopaminergic neurons and the formation of intracellular inclusion bodies, termed Lewy bodies, in surviving neurons. Accumulation of proteins in large insoluble cytoplasmic aggregates has been proposed to result, partly, from a failure in the function of intracellular protein degradation pathways. Evidence in support for such a hypothesis emerged in the beginning of the years 2000 with studies demonstrating structural and functional deficits in the ubiquitin-proteasome pathway in post-mortem nigral tissue of patients with Parkinson's disease. These fundamental findings have inspired the development of a new generation of animal models based on the use of proteasome inhibitors to disturb protein homeostasis and trigger nigral dopaminergic neurodegeneration. In this review, we provide an updated overview of the current approaches in employing proteasome inhibitors to model Parkinson's disease, with particular emphasis on rodent studies. In addition, the mechanisms underlying proteasome inhibition-induced cell death and the validity criteria (construct, face and predictive validity) of the model will be critically discussed. Due to its distinct, but highly relevant mechanism of inducing neuronal death, the proteasome inhibition model represents a useful addition to the repertoire of toxin-based models of Parkinson's disease that might provide novel clues to unravel the complex pathogenesis of this disorder.
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Affiliation(s)
| | | | - Ann Massie
- Correspondence to: Dr. Ann Massie, Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium. Tel.: +32 2 477 4502; E-mail:
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7
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La Cognata V, Maugeri G, D'Amico AG, Saccone S, Federico C, Cavallaro S, D'Agata V. Differential expression of PARK2 splice isoforms in an in vitro model of dopaminergic-like neurons exposed to toxic insults mimicking Parkinson's disease. J Cell Biochem 2017; 119:1062-1073. [PMID: 28688199 DOI: 10.1002/jcb.26274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 07/07/2017] [Indexed: 12/16/2022]
Abstract
Mutations in PARK2 (or parkin) are responsible for 50% of cases of autosomal-recessive juvenile-onset Parkinson's disease (PD). To date, 21 alternative splice variants of the human gene have been cloned. Yet most studies have focused on the full-length protein, whereas the spectrum of the parkin isoforms expressed in PD has never been investigated. In this study, the role of parkin proteins in PD neurodegeneration was explored for the first time by analyzing their expression profile in an in vitro model of PD. To do so, undifferentiated and all-trans-retinoic-acid (RA)-differentiated SH-SY5Y cells (which thereby acquire a PD-like phenotype) were exposed to PD-mimicking neurotoxins: 1-methyl-4-phenylpyridinium (MPP+ ) and 6-hydroxydopamine (6-OHDA) are widely used in PD models, whereas carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and carbobenzoxy-Leu-Leu-leucinal (MG132) interfere, respectively, with mitochondrial mitophagy and proteasomal degradation. Following treatment with each neurotoxin H1, the first parkin isoform to be cloned, was down-regulated compared to the respective controls both in undifferentiated and RA-differentiated cells. In contrast, the expression pattern of the minor splice isoforms varied as a function of the compound used: it was largely unchanged in both cell cultures (eg, H21-H6, H12, XP isoform) or it showed virtually opposite alterations in undifferentiated and RA-differentiated cells (eg, H20 and H3 isoform). This complex picture suggests that up- or down-regulation may be a direct effect of toxin exposure, and that the different isoforms may exert different actions in neurodegeneration via modulation of different molecular pathways.
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Affiliation(s)
- Valentina La Cognata
- Section of Human Anatomy and Histology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy.,Institute of Neurological Sciences, National Research Council, Catania, Italy
| | - Grazia Maugeri
- Section of Human Anatomy and Histology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Agata Grazia D'Amico
- Section of Human Anatomy and Histology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy.,Department of Human Science and Promotion of Quality of Life, San Raffaele Open University of Rome, Rome, Italy
| | - Salvatore Saccone
- Section of Animal Biology, Department of Biological, Geological, and Environmental Sciences, University of Catania, Catania, Italy
| | - Concetta Federico
- Section of Animal Biology, Department of Biological, Geological, and Environmental Sciences, University of Catania, Catania, Italy
| | | | - Velia D'Agata
- Section of Human Anatomy and Histology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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8
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N-Acetylcysteine in Combination with IGF-1 Enhances Neuroprotection against Proteasome Dysfunction-Induced Neurotoxicity in SH-SY5Y Cells. PARKINSONS DISEASE 2016; 2016:6564212. [PMID: 27774335 PMCID: PMC5059605 DOI: 10.1155/2016/6564212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 08/19/2016] [Accepted: 08/28/2016] [Indexed: 11/17/2022]
Abstract
Ubiquitin proteasome system (UPS) dysfunction has been implicated in the development of many neuronal disorders, including Parkinson's disease (PD). Previous studies focused on individual neuroprotective agents and their respective abilities to prevent neurotoxicity following a variety of toxic insults. However, the effects of the antioxidant N-acetylcysteine (NAC) on proteasome impairment-induced apoptosis have not been well characterized in human neuronal cells. The aim of this study was to determine whether cotreatment of NAC and insulin-like growth factor-1 (IGF-1) efficiently protected against proteasome inhibitor-induced cytotoxicity in SH-SY5Y cells. Our results demonstrate that the proteasome inhibitor, MG132, initiates poly(ADP-ribose) polymerase (PARP) cleavage, caspase 3 activation, and nuclear condensation and fragmentation. In addition, MG132 treatment leads to endoplasmic reticulum (ER) stress and autophagy-mediated cell death. All of these events can be attenuated without obvious reduction of MG132 induced protein ubiquitination by first treating the cells with NAC and IGF-1 separately or simultaneously prior to exposure to MG132. Moreover, our data demonstrated that the combination of the two proved to be significantly more effective for neuronal protection. Therefore, we conclude that the simultaneous use of growth/neurotrophic factors and a free radical scavenger may increase overall protection against UPS dysfunction-mediated cytotoxicity and neurodegeneration.
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Lv E, Deng J, Yu Y, Wang Y, Gong X, Jia J, Wang X. Nrf2-ARE signals mediated the anti-oxidative action of electroacupuncture in an MPTP mouse model of Parkinson's disease. Free Radic Res 2015; 49:1296-307. [PMID: 26118717 DOI: 10.3109/10715762.2015.1067696] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Oxidative stress and neuroinflammation are early events associated with dopaminergic neuronal degeneration in Parkinson's disease (PD). Previous studies indicated that electroacupuncture (EA) stimulation is effective in protecting dopaminergic neurons from degeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. In this study, we further characterized the effect of EA on MPTP-induced oxidative responses in the mouse dopamine system. We found that subacute administration of MPTP enhanced lipid and protein oxidation and reduced expression of endogenous antioxidant enzymes (such as superoxide dismutase and catalase) in the striatum. MPTP also reduced expression of an antioxidant transcription factor, nuclear factor-E2-related factor-2 (Nrf2), and Nrf2-regulated antioxidant enzymes (nicotinamide adenine dinucleotide phosphate quinone oxidoreductase-1 and heme oxygenase-1) in the striatum and/or midbrain. Using human placental alkaline phosphatase (hPAP) as a reporter of Nrf2-regulated gene expression in hPAP transgenic mice, we found that MPTP suppressed hPAP expression in the striatum and midbrain. Application of EA at an effective frequency (100 Hz) was sufficient to reverse these changes induced by MPTP. In addition, EA reduced microglia activation and astrogliosis in the striatum and midbrain, increased tyrosine hydroxylase levels in the striatum, and improved vertical movement in MPTP mice. These results provide further evidence supporting that EA produces a series of anti-oxidative effects that effectively counteract with the oxidative stress in the nigrostriatal dopamine system induced by MPTP in a mouse model of PD.
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Affiliation(s)
- E Lv
- a Departments of Neurobiology and Physiology , Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Capital Medical University; Beijing Institute for Brain Disorders , Beijing , 100069 , China
| | - J Deng
- a Departments of Neurobiology and Physiology , Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Capital Medical University; Beijing Institute for Brain Disorders , Beijing , 100069 , China
| | - Y Yu
- a Departments of Neurobiology and Physiology , Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Capital Medical University; Beijing Institute for Brain Disorders , Beijing , 100069 , China
| | - Y Wang
- a Departments of Neurobiology and Physiology , Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Capital Medical University; Beijing Institute for Brain Disorders , Beijing , 100069 , China
| | - X Gong
- a Departments of Neurobiology and Physiology , Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Capital Medical University; Beijing Institute for Brain Disorders , Beijing , 100069 , China
| | - J Jia
- a Departments of Neurobiology and Physiology , Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Capital Medical University; Beijing Institute for Brain Disorders , Beijing , 100069 , China
| | - X Wang
- a Departments of Neurobiology and Physiology , Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Capital Medical University; Beijing Institute for Brain Disorders , Beijing , 100069 , China
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10
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Lim KL. Ubiquitin–proteasome system dysfunction in Parkinson’s disease: current evidence and controversies. Expert Rev Proteomics 2014; 4:769-81. [DOI: 10.1586/14789450.4.6.769] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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11
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Xiong R, Siegel D, Ross D. The activation sequence of cellular protein handling systems after proteasomal inhibition in dopaminergic cells. Chem Biol Interact 2013; 204:116-24. [PMID: 23684743 PMCID: PMC3784407 DOI: 10.1016/j.cbi.2013.04.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/17/2013] [Accepted: 04/26/2013] [Indexed: 01/09/2023]
Abstract
Dysfunction of protein handling has been implicated in many neurodegenerative diseases and inhibition of the ubiquitin-proteasome system (UPS) has been linked to the formation of protein aggregates and proteinopathies in such diseases. While proteasomal inhibition could trigger an array of downstream protein handling changes including up-regulation of heat shock proteins (HSPs), induction of molecular chaperones, activation of the ER stress/unfolded protein response (UPR), autophagy and aggresome formation, little is known of the relationship of proteasomal inhibition to the sequence of activation of these diverse protein handling systems. In this study we utilized the reversible proteasome inhibitor MG132 and examined the activity of several major protein handling systems in the immortalized dopaminergic neuronal N27 cell line. In the early phase (up to 6h after proteasomal inhibition), MG132 induced time-dependent proteasomal inhibition which resulted in stimulation of the UPR, increased autophagic flux and stimulated heat shock protein response as determined by increased levels of phosphorylation of the eukaryotic translation initiation factor 2 alpha (eIF2α), C/EBP homologous protein (CHOP)/GADD153, turnover of autophagy related microtubule-associated protein 1 light chain 3 (LC3) and increased levels of Hsp70 respectively. After prolonged proteasomal inhibition induced by MG132, we observed the formation of vimentin-caged aggresome-like inclusion bodies. A recovery study after MG132-induced proteasomal inhibition indicated that the autophagy-lysosomal pathway participated in the clearance of aggresomes. Our data characterizes the relationship between proteasome inhibition and activation of other protein handling systems. These data also indicated that the induction of alternate protein handling systems and their temporal relationships may be important factors that determine the extent of accumulation of misfolded proteins in cells as a result of proteasome inhibition.
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Affiliation(s)
- Rui Xiong
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, United States
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12
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Hwang O. Role of oxidative stress in Parkinson's disease. Exp Neurobiol 2013; 22:11-7. [PMID: 23585717 PMCID: PMC3620453 DOI: 10.5607/en.2013.22.1.11] [Citation(s) in RCA: 411] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 03/08/2013] [Accepted: 03/08/2013] [Indexed: 01/26/2023] Open
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative movement disorder associated with a selective loss of the dopamine(DA)rgic neurons in the substantia nigra pars compacta and the degeneration of projecting nerve fibers in the striatum. Because there is currently no therapy that delays the neurodegenerative process, modification of the disease course by neuroprotective therapy is an important unmet clinical need. Toward this end, understanding cellular mechanisms that render the nigral neurons particularly vulnerable have been a subject of intensive research. Increasing evidence suggests that oxidative stress plays a major role. The metabolism of DA itself contributes to oxidative stress, resulting in modification of intracellular macromolecules whose functions are important for cell survival. Mitochondrial dysfunction and the consequent increase in reactive oxygen species also trigger a sequence of events that leads to cell demise. In addition, activated microglia produce nitric oxide and superoxide during neuroinflammatory responses, and this is aggravated by the molecules released by damaged DAergic neurons such as α-synuclein, neuromelanin and matrix metalloproteinase-3. Ways to reduce oxidative stress therefore can provide a therapeutic strategy. NAD(P)H:quinone reductase (NQO1) and other antioxidant enzymes, whose gene expression are commonly under the regulation of the transcription factor Nrf2, can serve as target proteins utilized toward development of disease-modifying therapy for PD.
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Affiliation(s)
- Onyou Hwang
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Korea
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Kumar A, Singh BK, Ahmad I, Shukla S, Patel DK, Srivastava G, Kumar V, Pandey HP, Singh C. Involvement of NADPH oxidase and glutathione in zinc-induced dopaminergic neurodegeneration in rats: similarity with paraquat neurotoxicity. Brain Res 2011; 1438:48-64. [PMID: 22244881 DOI: 10.1016/j.brainres.2011.12.028] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 11/29/2022]
Abstract
An association between excessive zinc (Zn) accumulation in brain and incidences of Parkinson's disease (PD) has been shown in several epidemiological and experimental investigations. The involvement of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and glutathione (GSH) in the pathogenesis of PD has also been proposed in a few studies. Despite the implicated role of oxidative stress in PD, the entire mechanism of Zn-induced dopaminergic neurodegeneration has not yet been clearly understood. The present study aimed to investigate the involvement of NADPH oxidase and GSH in Zn-induced dopaminergic neurodegeneration and also to assess its similarity with paraquat (PQ)-induced rat model of PD. Male Wistar rats were treated either with Zn (20 mg/kg; i.p.) or PQ (5 mg/kg; i.p.) in the presence and absence of NADPH oxidase inhibitor, apocynin (10 mg/kg; i.p.) and a GSH precursor, N-acetyl cysteine (NAC; 200 mg/kg; i.p.) either alone or in combination along with the respective controls. Apocynin and/or NAC pre-treatment significantly alleviated Zn- and PQ-induced changes in neurobehavioral deficits, number of dopaminergic neurons and contents of the striatal dopamine and its metabolites. Apocynin and/or NAC also mitigated Zn- and PQ-induced alterations in oxidative stress, NADPH oxidase activation and cytochrome c release, caspases-9 and -3 activation and CD11b expression. The results obtained thus suggest that Zn induces oxidative stress via the activation of NADPH oxidase and depletion of GSH, which in turn activate the apoptotic machinery leading to dopaminergic neurodegeneration similar to PQ.
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Affiliation(s)
- Ashutosh Kumar
- Council of Scientific and Industrial Research-Indian Institute of Toxicology Research (CSIR-IITR), Lucknow-226001, India
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14
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Zahid M, Saeed M, Yang L, Beseler C, Rogan E, Cavalieri EL. Formation of dopamine quinone-DNA adducts and their potential role in the etiology of Parkinson's disease. IUBMB Life 2011; 63:1087-93. [PMID: 22045657 PMCID: PMC4418631 DOI: 10.1002/iub.538] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 06/13/2011] [Indexed: 11/09/2022]
Abstract
The neurotransmitter dopamine is oxidized to its quinone (DA-Q), which at neutral pH undergoes intramolecular cyclization by 1,4-Michael addition, followed by oxidation to form leukochrome, then aminochrome, and finally neuromelanin. At lower pH, the amino group of DA is partially protonated, allowing the competitive intermolecular 1,4-Michael addition with nucleophiles in DNA to form the depurinating adducts, DA-6-N3Ade and DA-6-N7Gua. Catechol estrogen-3,4-quinones react by 1,4-Michael addition to form the depurinating 4-hydroxyestrone(estradiol)-1-N3Ade [4-OHE1(E2)-1-N3Ade] and 4-OHE1(E2)-1-N7Gua adducts, which are implicated in the initiation of breast and other human cancers. The effect of pH was studied by reacting tyrosinase-activated DA with DNA and measuring the formation of depurinating adducts. The most adducts were formed at pH 4, 5, and 6, and their level was nominal at pH 7 and 8. The N3Ade adduct depurinated instantaneously, but N7Gua had a half-life of 3 H. The slow loss of the N7Gua adduct is analogous to that observed in previous studies of natural and synthetic estrogens. The antioxidants N-acetylcysteine and resveratrol efficiently blocked formation of the DA-DNA adducts. Thus, slightly acidic conditions render competitive the reaction of DA-Q with DNA to form depurinating adducts. We hypothesize that formation of these adducts could lead to mutations that initiate Parkinson's disease. If so, use of N-acetylcysteine and resveratrol as dietary supplements may prevent initiation of this disease.
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Affiliation(s)
- Muhammad Zahid
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, NE
| | - Muhammad Saeed
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, NE
| | - Li Yang
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, NE
- Department of Environmental, Agricultural and Occupational Health, College of Public Health, University of Nebraska Medical Center, Omaha NE
| | - Cheryl Beseler
- Department of Psychology, Colorado State University, Fort Collins, CO
| | - Eleanor Rogan
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, NE
- Department of Environmental, Agricultural and Occupational Health, College of Public Health, University of Nebraska Medical Center, Omaha NE
| | - Ercole L. Cavalieri
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, NE
- Department of Environmental, Agricultural and Occupational Health, College of Public Health, University of Nebraska Medical Center, Omaha NE
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15
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α-Synuclein negatively regulates protein kinase Cδ expression to suppress apoptosis in dopaminergic neurons by reducing p300 histone acetyltransferase activity. J Neurosci 2011; 31:2035-51. [PMID: 21307242 DOI: 10.1523/jneurosci.5634-10.2011] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We recently demonstrated that protein kinase Cδ (PKCδ), an important member of the novel PKC family, is a key oxidative stress-sensitive kinase that can be activated by caspase-3-dependent proteolytic cleavage to induce dopaminergic neuronal cell death. We now report a novel association between α-synuclein (αsyn), a protein associated with the pathogenesis of Parkinson's disease, and PKCδ, in which αsyn negatively modulates the p300- and nuclear factor-κB (NFκB)-dependent transactivation to downregulate proapoptotic kinase PKCδ expression and thereby protects against apoptosis in dopaminergic neuronal cells. Stable expression of human wild-type αsyn at physiological levels in dopaminergic neuronal cells resulted in an isoform-dependent transcriptional suppression of PKCδ expression without changes in the stability of mRNA and protein or DNA methylation. The reduction in PKCδ transcription was mediated, in part, through the suppression of constitutive NFκB activity targeted at two proximal PKCδ promoter κB sites. This occurred independently of NFκB/IκBα (inhibitor of κBα) nuclear translocation but was associated with decreased NFκB-p65 acetylation. Also, αsyn reduced p300 levels and its HAT (histone acetyltransferase) activity, thereby contributing to diminished PKCδ transactivation. Importantly, reduced PKCδ and p300 expression also were observed within nigral dopaminergic neurons in αsyn-transgenic mice. These findings expand the role of αsyn in neuroprotection by modulating the expression of the key proapoptotic kinase PKCδ in dopaminergic neurons.
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16
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Jeon SM, Cheon SM, Bae HR, Kim JW, Kim SU. Selective susceptibility of human dopaminergic neural stem cells to dopamine-induced apoptosis. Exp Neurobiol 2010; 19:155-64. [PMID: 22110355 PMCID: PMC3214785 DOI: 10.5607/en.2010.19.3.155] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 11/05/2010] [Indexed: 12/27/2022] Open
Abstract
Dysfunctions of ubiquitin-proteasome system and toxicity of dopamine have been known as the key mechanisms in the pathogenesis of Parkinson's disease (PD) and proteasome inhibitors are widely used in experimental models of PD to reproduce cell death of dopaminergic neurons. In the present study, immortalized human neural stem cells (HB1.F3, F3) and those transfected with human aromatic acid decarboxylase gene (F3.AADC), were used to investigate the mechanism of selective dopaminergic neuronal cell death mediated by dopamine or proteasome inhibitors. Flow cytometric analysis revealed that F3.AADC was more susceptible to dopamine than parental F3 cell which does not carry dopaminergic phenotype. The dopamine-induced apoptosis was mediated by activation of caspases 3 and 9 and cleavage of PARP. Proteasome inhibitors also induced apoptosis in dose-dependent manner but there was no difference between cell types. Prolonged exposure to subtoxic dose of proteasome inhibitors further enhanced dopamine-induced apoptosis in the F3.AADC, and increased presence of alpha-synuclein and ubiquitin-positive inclusions was noted in the cytoplasm of apoptotic cells by immunocytochemistry. These findings indicate that dopaminergic cells are selectively susceptible to dopamine toxicity and prolonged suppression of proteasome system further enhances selective sensitivity to dopamine toxicity. Chronic subtoxic proteasomal dysfunction of dopaminergic cells might contribute to selective cell death of dopaminergic neurons during the pathogenesis of Parkinson's disease.
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Affiliation(s)
- Sung-Man Jeon
- Department of Neurology, Bongseng Memorial Hospital, Busan 601-723, Korea
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17
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Dinkova-Kostova AT, Talalay P. NAD(P)H:quinone acceptor oxidoreductase 1 (NQO1), a multifunctional antioxidant enzyme and exceptionally versatile cytoprotector. Arch Biochem Biophys 2010; 501:116-23. [PMID: 20361926 PMCID: PMC2930038 DOI: 10.1016/j.abb.2010.03.019] [Citation(s) in RCA: 527] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 03/17/2010] [Accepted: 03/25/2010] [Indexed: 12/30/2022]
Abstract
NAD(P)H:quinone acceptor oxidoreductase 1 (NQO1) is a widely-distributed FAD-dependent flavoprotein that promotes obligatory 2-electron reductions of quinones, quinoneimines, nitroaromatics, and azo dyes, at rates that are comparable with NADH or NADPH. These reductions depress quinone levels and thereby minimize opportunities for generation of reactive oxygen intermediates by redox cycling, and for depletion of intracellular thiol pools. NQO1 is a highly-inducible enzyme that is regulated by the Keap1/Nrf2/ARE pathway. Evidence for the importance of the antioxidant functions of NQO1 in combating oxidative stress is provided by demonstrations that induction of NQO1 levels or their depletion (knockout, or knockdown) are associated with decreased and increased susceptibilities to oxidative stress, respectively. Furthermore, benzene genotoxicity is markedly enhanced when NQO1 activity is compromised. Not surprisingly, human polymorphisms that suppress NQO1 activities are associated with increased predisposition to disease. Recent studies have uncovered protective roles for NQO1 that apparently are unrelated to its enzymatic activities. NQO1 binds to and thereby stabilizes the important tumor suppressor p53 against proteasomal degradation. Indeed, NQO1 appears to regulate the degradative fate of other proteins. These findings suggest that NQO1 may exercise a selective "gatekeeping" role in regulating the proteasomal degradation of specific proteins, thereby broadening the cytoprotective role of NQO1 far beyond its highly effective antioxidant functions.
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Affiliation(s)
- Albena T. Dinkova-Kostova
- Biomedical Research Institute, University of Dundee, Dundee, Scotland, UK
- Lewis B. and Dorothy Cullman Chemoprotection Center and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Paul Talalay
- Lewis B. and Dorothy Cullman Chemoprotection Center and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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18
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Chan KM, Rajab NF, Siegel D, Din LB, Ross D, Inayat-Hussain SH. Goniothalamin induces coronary artery smooth muscle cells apoptosis: the p53-dependent caspase-2 activation pathway. Toxicol Sci 2010; 116:533-48. [PMID: 20498002 DOI: 10.1093/toxsci/kfq151] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Goniothalamin (GN), a styryl-lactone isolated from Goniothalamus andersonii, has been demonstrated to possess antirestenostic properties by inducing apoptosis on coronary artery smooth muscle cells (CASMCs). In this study, the molecular mechanisms of GN-induced CASMCs apoptosis were further elucidated. Apoptosis assessment based on the externalization of phosphatidylserine demonstrated that GN induces CASMCs apoptosis in a concentration-dependent manner. The GN-induced DNA damage occurred with concomitant elevation of p53 as early as 2 h, demonstrating an upstream signal for apoptosis. However, the p53 elevation in GN-treated CASMCs was independent of NAD(P)H: quinone oxidoreductase 1 and Mdm-2 expression. An increase in hydrogen peroxide and reduction in free thiols confirmed the role for oxidative stress in GN treatment. Pretreatment with the pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-FMK) that significantly abrogated GN-induced CASMCs apoptosis suggested the involvement of caspase(s). The role of apical caspase-2, -8, and -9 was then investigated, and sequential activation of caspase-2 and -9 but not caspase-8 leading to downstream caspase-3 cleavage was observed in GN-treated CASMCs. Reduction of ATP level and decrease in oxygen consumption further confirmed the role of mitochondria in GN-induced apoptosis in CASMCs. The mitochondrial release of cytochrome c was seen without mitochondrial membrane potential loss and was independent of cardiolipin. These data provide insight into the mechanisms of GN-induced apoptosis, which may have important implications in the development of drug-eluting stents.
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Affiliation(s)
- Kok Meng Chan
- Department of Biomedical Science, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
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19
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skn-1-Dependent and -independent regulation of aip-1 expression following metabolic stress in Caenorhabditis elegans. Mol Cell Biol 2010; 30:2651-67. [PMID: 20351174 DOI: 10.1128/mcb.01340-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Maintenance of a stable, properly folded, and catalytically active proteome is a major challenge to organisms in the face of multiple internal and external stresses which damage proteins and lead to protein misfolding. Here we show that internal metabolic stress produced by reactive intermediates resulting from tyrosine degradation triggers the expression of the aip-1 gene, which is critical in responses to the environmental toxin arsenic and the clearance of unstable polyglutamine and Abeta proteins. aip-1 acts via binding to the proteosome and enhancing proteosomal function. We find that full induction of aip-1 depends on the oxidative-stress-responsive skn-1 transcription factor but significant induction still occurs without skn-1. Importantly, activation of skn-1 with wdr-23(RNAi), which dramatically induces the expression of other skn-1 target genes, produces a minimal increase in aip-1 expression. This suggests that the previously demonstrated specificity in aip-1/AIRAP induction could reflect the actions of multiple synergistic activators, such as the heat shock factor homolog hsf-1, which we also find is required for full induction. These may be triggered by proteosome dysfunction, as we find that this event links the multiple inducers of aip-1. Together, our results show that cell stress triggers aip-1 expression by both skn-1-dependent and -independent pathways.
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20
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Abstract
Caspase-2 is the most evolutionarily conserved of all the caspases, yet it has a poorly defined role in apoptotic pathways. This is mainly due to a dearth of techniques to determine the activation status of caspase-2 and the lack of an abnormal phenotype in caspase-2 deficient mice. Nevertheless, emerging evidence suggests that caspase-2 may have important functions in a number of stress-induced cell death pathways, in cell cycle maintenance and regulation of tumour progression. This review discusses recent advances that have been made to help elucidate the true role of this elusive caspase and the potential contribution of caspase-2 to the pathology of human diseases including cancer.
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Affiliation(s)
- Lisa Bouchier-Hayes
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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21
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Sun F, Kanthasamy A, Anantharam V, Kanthasamy AG. Mitochondrial accumulation of polyubiquitinated proteins and differential regulation of apoptosis by polyubiquitination sites Lys-48 and -63. J Cell Mol Med 2009; 13:1632-1643. [PMID: 19432818 DOI: 10.1111/j.1582-4934.2009.00775.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Proteins tagged with lysine (Lys, K) 48 polyubiquitins chains are destined for degradation by the 26S proteasomal system. Impairment of the ubiquitin proteasome system (UPS) function culminates in the accumulation of polyubiquitinated proteins in many neurodegenerative conditions including Parkinson's disease (PD). Nevertheless, the cellular mechanisms underlying cell death induced by an impaired UPS are still not clear. Intriguingly, recent studies indicate that several proteins associated with familial PD are capable of promoting the assembly of Lys-63 polyubiquitin chains. Therefore, the objective of this study was to examine the role of K48 and K63 ubiquitination in mitochondria-mediated apoptosis in in vitro models of dopaminergic degeneration. Exposure of the widely used proteasome inhibitor MG-132 to dopaminergic neuronal cell line (N27) induced a rapid accumulation of polyubiquitinated proteins in the mitochondria. This appears to result in the preferential association of ubiquitin conjugates in the outer membrane and polyubiquitination of outer membrane proteins. Interestingly, the ubiquitin(K48R) mutant effectively rescued cells from MG-132-induced mitochondrial apoptosis without altering the antioxidant status of cells; whereas the ubiquitin(K63R) mutant augmented the proapoptotic effect of MG-132. Herein, we report a novel conclusion that polyubiquitinated proteins, otherwise subjected to proteasomal degradation, preferentially accumulate in the mitochondria during proteolytic stress; and that polyubiquitination of Lys-48 and Lys-63 are key determinants of mitochondria-mediated cell death during proteasomal dysfunction. Together, these findings yield novel insights into a crosstalk between the UPS and mitochondria in dopaminergic neuronal cells.
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Affiliation(s)
- Faneng Sun
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Arthi Kanthasamy
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Vellareddy Anantharam
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Anumantha G Kanthasamy
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
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Peroz D, Dahimène S, Baró I, Loussouarn G, Mérot J. LQT1-associated mutations increase KCNQ1 proteasomal degradation independently of Derlin-1. J Biol Chem 2008; 284:5250-6. [PMID: 19114714 DOI: 10.1074/jbc.m806459200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mutations in the potassium channel KCNQ1 that determine retention of the mutated proteins in the endoplasmic reticulum (ER) are associated with the autosomal dominant negative Romano-Ward LQT1 cardiac syndrome. In the present study, we have analyzed the consequences and the potential molecular mechanisms involved in the ER retention of three Romano-Ward mutations located in KCNQ1 N terminus (Y111C, L114P, and P117L). We showed that the mutant KCNQ1 proteins exhibited reduced expression levels with respect to wild-type (WT)-KCNQ1. Radiolabeling pulse-chase experiments revealed that the lower expression levels did not result from reduced rate of synthesis. Instead, using a combination of Western blot and pulse-chase experiments, we showed that the mutant channel Y111C-KCNQ1, used as a model, was ubiquitinated and degraded in the proteasome more rapidly (t((1/2)) = 82 min) than WT-KCNQ1 channel (t((1/2)) = 113 min). On the other hand, KCNQ1 degradation did not appear to involve the GTP-dependent pathway. We also showed that KCNE1 stabilized both wild-type and Y111C proteins. To identify potential actors involved in KCNQ1 degradation, we studied the implication of the ER-resident protein Derlin-1 in KCNQ1 degradation. We showed that although KCNQ1 and Derlin-1 share the same molecular complex and co-immunoprecipitate when co-expressed in HEK293FT cells, Derlin-1 did not affect KCNQ1 steady state expression and degradation. These data were confirmed in T84 cells that express endogenous KCNQ1 and Derlin-1. Small interfering RNA knock-down of Derlin-1 did not modify KCNQ1 expression level, and no interaction between endogenous KCNQ1 and Derlin-1 could be detected.
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