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Kretov DA, Folkes L, Mora-Martin A, Walawalkar IA, Imrat, Syedah N, Vanuytsel K, Moxon S, Murphy GJ, Cifuentes D. The miR-144/Hmgn2 regulatory axis orchestrates chromatin organization during erythropoiesis. Nat Commun 2024; 15:3821. [PMID: 38714702 PMCID: PMC11076586 DOI: 10.1038/s41467-024-47982-2] [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: 07/30/2023] [Accepted: 04/17/2024] [Indexed: 05/10/2024] Open
Abstract
Differentiation of stem and progenitor cells is a highly regulated process that involves the coordinated action of multiple layers of regulation. Here we show how the post-transcriptional regulatory layer instructs the level of chromatin regulation via miR-144 and its targets to orchestrate chromatin condensation during erythropoiesis. The loss of miR-144 leads to impaired chromatin condensation during erythrocyte maturation. Among the several targets of miR-144 that influence chromatin organization, the miR-144-dependent regulation of Hmgn2 is conserved from fish to humans. Our genetic probing of the miR-144/Hmgn2 regulatory axis establish that intact miR-144 target sites in the Hmgn2 3'UTR are necessary for the proper maturation of erythrocytes in both zebrafish and human iPSC-derived erythroid cells while loss of Hmgn2 rescues in part the miR-144 null phenotype. Altogether, our results uncover miR-144 and its target Hmgn2 as the backbone of the genetic regulatory circuit that controls the terminal differentiation of erythrocytes in vertebrates.
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Affiliation(s)
- Dmitry A Kretov
- Department of Biochemistry and Cell Biology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Leighton Folkes
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Alexandra Mora-Martin
- Department of Biochemistry and Cell Biology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Isha A Walawalkar
- Department of Biochemistry and Cell Biology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Imrat
- Department of Biochemistry and Cell Biology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Noreen Syedah
- Department of Biochemistry and Cell Biology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Kim Vanuytsel
- Center for Regenerative Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
- Section of Hematology and Oncology, Department of Medicine, Boston Medical Center, Boston, MA, USA
- Amyloidosis Center, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
| | - Simon Moxon
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - George J Murphy
- Center for Regenerative Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
- Section of Hematology and Oncology, Department of Medicine, Boston Medical Center, Boston, MA, USA
| | - Daniel Cifuentes
- Department of Biochemistry and Cell Biology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA.
- Department of Virology, Immunology and Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA.
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Riederer P, Monoranu C, Strobel S, Iordache T, Sian-Hülsmann J. Iron as the concert master in the pathogenic orchestra playing in sporadic Parkinson's disease. J Neural Transm (Vienna) 2021; 128:1577-1598. [PMID: 34636961 PMCID: PMC8507512 DOI: 10.1007/s00702-021-02414-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/29/2021] [Indexed: 02/07/2023]
Abstract
About 60 years ago, the discovery of a deficiency of dopamine in the nigro-striatal system led to a variety of symptomatic therapeutic strategies to supplement dopamine and to substantially improve the quality of life of patients with Parkinson's disease (PD). Since these seminal developments, neuropathological, neurochemical, molecular biological and genetic discoveries contributed to elucidate the pathology of PD. Oxidative stress, the consequences of reactive oxidative species, reduced antioxidative capacity including loss of glutathione, excitotoxicity, mitochondrial dysfunction, proteasomal dysfunction, apoptosis, lysosomal dysfunction, autophagy, suggested to be causal for ɑ-synuclein fibril formation and aggregation and contributing to neuroinflammation and neural cell death underlying this devastating disorder. However, there are no final conclusions about the triggered pathological mechanism(s) and the follow-up of pathological dysfunctions. Nevertheless, it is a fact, that iron, a major component of oxidative reactions, as well as neuromelanin, the major intraneuronal chelator of iron, undergo an age-dependent increase. And ageing is a major risk factor for PD. Iron is significantly increased in the substantia nigra pars compacta (SNpc) of PD. Reasons for this finding include disturbances in iron-related import and export mechanisms across the blood-brain barrier (BBB), localized opening of the BBB at the nigro-striatal tract including brain vessel pathology. Whether this pathology is of primary or secondary importance is not known. We assume that there is a better fit to the top-down hypotheses and pathogens entering the brain via the olfactory system, then to the bottom-up (gut-brain) hypothesis of PD pathology. Triggers for the bottom-up, the dual-hit and the top-down pathologies include chemicals, viruses and bacteria. If so, hepcidin, a regulator of iron absorption and its distribution into tissues, is suggested to play a major role in the pathogenesis of iron dyshomeostasis and risk for initiating and progressing ɑ-synuclein pathology. The role of glial components to the pathology of PD is still unknown. However, the dramatic loss of glutathione (GSH), which is mainly synthesized in glia, suggests dysfunction of this process, or GSH uptake into neurons. Loss of GSH and increase in SNpc iron concentration have been suggested to be early, may be even pre-symptomatic processes in the pathology of PD, despite the fact that they are progression factors. The role of glial ferritin isoforms has not been studied so far in detail in human post-mortem brain tissue and a close insight into their role in PD is called upon. In conclusion, "iron" is a major player in the pathology of PD. Selective chelation of excess iron at the site of the substantia nigra, where a dysfunction of the BBB is suggested, with peripherally acting iron chelators is suggested to contribute to the portfolio and therapeutic armamentarium of anti-Parkinson medications.
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Affiliation(s)
- P Riederer
- Clinic and Policlinic for Psychiatry, Psychosomatics and Psychotherapy, University Hospital Wuerzburg, University of Wuerzburg, Wuerzburg, Germany. .,Department of Psychiatry, University of Southern Denmark, Odense, Denmark.
| | - C Monoranu
- Institute of Pathology, Department of Neuropathology, University of Wuerzburg, Wuerzburg, Germany
| | - S Strobel
- Institute of Pathology, Department of Neuropathology, University of Wuerzburg, Wuerzburg, Germany
| | - T Iordache
- George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, Târgu Mureș, Romania
| | - J Sian-Hülsmann
- Department of Medical Physiology, University of Nairobi, P.O. Box 30197, Nairobi, 00100, Kenya
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Tyrosinase deficiency increases protein carbonyl content in substantia nigra of mice administered retinol palmitate. Neuroreport 2020; 32:121-124. [PMID: 33290311 DOI: 10.1097/wnr.0000000000001566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Tyrosinase is a key enzyme for the biosynthesis of melanin pigments in peripheral tissues such as skin and retina. Although tyrosinase activity is specifically detected in melanocytes, several studies have shown the expression and enzymatic activity of tyrosinase in the central nervous system, especially in the midbrain substantia nigra. In the present study, we investigated the antioxidative effects of tyrosinase on protein damage in the substantia nigra of mice. C57BL/10JMsHir (B10) and tyrosinase-deficient albino B10.C-Tyrc/Hir (B10-c) mice were intraperitoneally administered retinol palmitate to induce oxidative stress, and the protein carbonyl content, a hallmark of protein oxidative damage, was examined in the substantia nigra. Retinol palmitate administration was found to decrease catalase activity in the substantia nigra of both B10 and B10-c mice, suggesting the induction of oxidative stress due to imbalanced antioxidant systems. In this model, we found that tyrosinase deficiency markedly increases the protein carbonyl content in the substantia nigra. Thus, we concluded that tyrosinase activity prevents protein damage in the substantia nigra of mice that were challenged with oxidative stress. These findings provide novel insight into the physiological role of tyrosinase in the central nervous system.
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Pdgf signalling guides neural crest contribution to the haematopoietic stem cell specification niche. Nat Cell Biol 2017; 19:457-467. [PMID: 28394883 PMCID: PMC5546139 DOI: 10.1038/ncb3508] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/14/2017] [Indexed: 12/14/2022]
Abstract
Haematopoietic stem cells (HSCs) support maintenance of the haematopoietic and immune systems throughout the life of vertebrates, and are the therapeutic component of bone marrow transplants. Understanding native specification of HSCs, to uncover key signals that might help improve in vitro directed differentiation protocols, has been a longstanding biomedical goal. The current impossibility of specifying true HSCs in vitro suggests that key signals remain unknown. We speculated that such signals might be presented by surrounding “niche” cells, but no such cells have been defined. Here we demonstrate in zebrafish, that trunk neural crest (NC) physically associate with HSC precursors in the dorsal aorta (DA) just prior to initiation of the definitive haematopoietic programme. Preventing association of the NC with the DA leads to loss of HSCs. Our results define NC as key cellular components of the HSC specification niche that can be profiled to identify unknown HSC specification signals.
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Zhang C, Liu J, Jin N, Zhang G, Xi Y, Liu H. SiRNA Targeting mTOR Effectively Prevents the Proliferation and Migration of Human Lens Epithelial Cells. PLoS One 2016; 11:e0167349. [PMID: 27911920 PMCID: PMC5135089 DOI: 10.1371/journal.pone.0167349] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/12/2016] [Indexed: 12/14/2022] Open
Abstract
Posterior capsule opacification (PCO) is the most common complication that causes visual decrease after extracapsular cataract surgery. The primary cause of PCO formation is the proliferation of the residual lens epithelial cells (LECs). The mammalian target of rapamycin (mTOR) plays an important role in the growth and migration of LECs. In the current study, we used small interfering RNA (siRNA) to specifically attenuate mTOR in human lens epithelial B3 cells (HLE B3). We aimed to examine the effect of mTOR-siRNA on the proliferation, migration and epithelial-to-mesenchymal transition (EMT) of HLE B3 cells and explore the underlying mechanisms. The mTOR-siRNA was transfected into HLE B3 cells using lipofectamine 2000. The mRNA and protein levels of mTOR were examined to confirm the efficiency of mTOR-siRNA. The levels of mRNA and protein as well as the activity of mTOR down-stream effectors p70 ribosomal protein S6 kinase (p70S6K) and protein kinase B (PKB, AKT) were examined using real-time PCR or Western blot, respectively. The cell proliferation was determined using cell counting kit (CCK) 8 and cell growth curve assay. The cell migration was examined using Transwell system and Scratch assay. MTOR-siRNA effectively eliminated mTOR mRNA and protein. The proliferation and migration were significantly suppressed by mTOR-siRNA transfection. mTOR-siRNA reduced the mRNA of p70S6K and AKT in a time-dependent manner. Furthermore, the phosphorylation of p70S6K and AKT was decreased by mTOR-siRNA. MTOR-siRNA also eliminated the formation of mTORC1 and mTORC2 protein complex and blocked the transforming growth factor (TGF)-β-induced EMT. Our results suggested that mTOR-siRNA could effectively inhibit the proliferation, migration and EMT of HLE B3 cells through the inhibition of p70S6K and AKT. These results indicated that mTOR-siRNA might be an effective agent inhibiting HLE cells growth and EMT following cataract surgery and provide an alternative therapy for preventing PCO.
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Affiliation(s)
- Chunmei Zhang
- Department of Ophthalmology, the First Affiliated Hospital of Harbin Medical University, Harbin, P.R. China
| | - Jingjing Liu
- Department of Ophthalmology, the First Affiliated Hospital of Harbin Medical University, Harbin, P.R. China
| | - Na Jin
- Department of Ophthalmology, the First Affiliated Hospital of Harbin Medical University, Harbin, P.R. China
| | - Guiming Zhang
- Department of Ophthalmology, No.2 Hospital of Xiamen, Fujian, P.R. China
| | - Yahui Xi
- Department of Ophthalmology, the First Affiliated Hospital of Harbin Medical University, Harbin, P.R. China
| | - Hongling Liu
- Department of Ophthalmology, the First Affiliated Hospital of Harbin Medical University, Harbin, P.R. China
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Tan JBL, Lim YY. Antioxidant and tyrosinase inhibition activity of the fertile fronds and rhizomes of three different Drynaria species. BMC Res Notes 2015; 8:468. [PMID: 26395256 PMCID: PMC4580379 DOI: 10.1186/s13104-015-1414-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 09/07/2015] [Indexed: 11/28/2022] Open
Abstract
Background For generations, the rhizomes of Drynaria ferns have been used as traditional medicine in Asia. Despite this, the bioactivities of Drynaria rhizomes and leaves have rarely been studied scientifically. Methods This study evaluates the antioxidant properties of the methanolic extracts of the fertile fronds and rhizomes from three species in this genus: Drynaria quercifolia, Drynaria rigidula and Drynaria sparsisora. The phenolic and flavonoid contents of the samples were respectively quantified with the total phenolic content (TPC) and total flavonoid content (TFC) assays, while the antioxidant activities were determined via measuring the DPPH radical scavenging activity (FRS), ferric reducing power (FRP), ferrous ion chelating (FIC) activity and lipid peroxidation inhibition (LPI). The tyrosinase inhibition activity of all three species was also reported. Results The fertile fronds of D. quercifolia were found to exhibit the highest overall TPC (2939 ± 469 mg GAE/100 g) and antioxidant activity amongst all the samples, and the fertile fronds of D. quercifolia and D. rigidula exhibited superior TPC and FRP compared to their rhizomes, despite only the latter being widely used in traditional medicine. The fronds of D. quercifolia had high tyrosinase inhibition activity (56.6 ± 5.0 %), but most of the Drynaria extracts showed unexpected tyrosinase enhancement instead, particularly for D. sparsisora’s fronds. Conclusion The high bioactivity of the fertile fronds in the fern species indicate that there is value in further research on the fronds of ferns which are commonly used mostly, or only, for their rhizomes.
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Affiliation(s)
- Joash Ban Lee Tan
- School of Science, Monash University Malaysia, Bandar Sunway, 46150, Petaling Jaya, Selangor, Malaysia.
| | - Yau Yan Lim
- School of Science, Monash University Malaysia, Bandar Sunway, 46150, Petaling Jaya, Selangor, Malaysia.
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Favre E, Daina A, Carrupt PA, Nurisso A. Modeling the met form of human tyrosinase: a refined and hydrated pocket for antagonist design. Chem Biol Drug Des 2014; 84:206-15. [PMID: 24612747 DOI: 10.1111/cbdd.12306] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/31/2014] [Indexed: 11/30/2022]
Abstract
Tyrosinases are type 3 copper proteins involved in melanin biosynthesis, responsible for skin and hair color in mammals. To steer tyrosinase inhibitor discovery for therapeutic and cosmetic purposes, structural information about human tyrosinase is necessary. As this protein has never been crystallized so far, we derived a robust homology model built using structural information from Streptomyces castaneoglobisporus and Ipomea batata catecholoxidase enzymes. The active site containing two copper atoms in co-ordination with six histidine residues was refined through an optimization protocol based on molecular mechanics parameters for copper co-ordination and charges calculated by quantum mechanics methods. Five structural water molecules and a hydroxyl ion were found to be essential for optimization. The superimposition of the human homology model on crystallographic structures of tyrosinases from other species revealed similar overall backbone topologies, active site conformations, and conserved water molecules. Phenylthiourea (PTU), the tyrosinase inhibitor of reference, was then docked into the solvated human active pocket. A binding mode consistent with crystallographic information was obtained. Taken together, these findings demonstrated that the human tyrosinase model, deposited in the Protein Model Database, is a reliable structure for future rational inhibitor design projects.
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Affiliation(s)
- Elisabeth Favre
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, Quai Ernest-Ansermet, CH-1211, Geneva, Switzerland
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Asanuma M, Miyazaki I, Diaz-Corrales FJ, Higashi Y, Namba M, Ogawa N. Transplantation of melanocytes obtained from the skin ameliorates apomorphine-induced abnormal behavior in rodent hemi-parkinsonian models. PLoS One 2013; 8:e65983. [PMID: 23776585 PMCID: PMC3680415 DOI: 10.1371/journal.pone.0065983] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 04/30/2013] [Indexed: 11/18/2022] Open
Abstract
Tyrosinase, which catalyzes both the hydroxylation of tyrosine and consequent oxidation of L-DOPA to form melanin in melanocytes, is also expressed in the brain, and oxidizes L-DOPA and dopamine. Replacement of dopamine synthesis by tyrosinase was reported in tyrosine hydroxylase null mice. To examine the potential benefits of autograft cell transplantation for patients with Parkinson’s disease, tyrosinase-producing cells including melanocytes, were transplanted into the striatum of hemi-parkinsonian model rats or mice lesioned with 6-hydroxydopamine. Marked improvement in apomorphine-induced rotation was noted at day 40 after intrastriatal melanoma cell transplantation. Transplantation of tyrosinase cDNA-transfected hepatoma cells, which constitutively produce L-DOPA, resulted in marked amelioration of the asymmetric apomorphine-induced rotation in hemi-parkinsonian mice and the effect was present up to 2 months. Moreover, parkinsonian mice transplanted with melanocytes from the back skin of black newborn mice, but not from albino mice, showed marked improvement in the apomorphine-induced rotation behavior up to 3 months after the transplantation. Dopamine-positive signals were seen around the surviving transplants in these experiments. Taken together with previous studies showing dopamine synthesis and metabolism by tyrosinase, these results highlight therapeutic potential of intrastriatal autograft cell transplantation of melanocytes in patients with Parkinson’s disease.
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Affiliation(s)
- Masato Asanuma
- Department of Brain Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
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Lee BH, Kim JH, Kim JM, Heo SH, Kang M, Kim GH, Choi JH, Yoo HW. The early molecular processes underlying the neurological manifestations of an animal model of Wilson's disease. Metallomics 2013; 5:532-40. [PMID: 23519153 DOI: 10.1039/c3mt20243g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Long-Evans Cinnamon (LEC) rat shows age-dependent hepatic manifestations that are similar to those of Wilson's disease (WD). The pathogenic process in the brain has, however, not been evaluated in detail due to the rarity of the neurological symptoms. However, copper accumulation is noted in LEC rat brain tissue from 24 weeks of age, which results in oxidative injuries. The current study investigated the gene expression profiles of LEC rat brains at 24 weeks of age in order to identify the important early molecular changes that underlie the development of neurological symptoms in WD. Biological ontology-based analysis revealed diverse altered expressions of the genes related to copper accumulation. Of particular interest, we found altered expression of genes connected to mitochondrial respiration (Sdhaf2 and Ndufb7), calcineurin-mediated cellular processes (Ppp3ca, Ppp3cb, and Camk2a), amyloid precursor protein (Anks1b and A2m) and alpha-synuclein (Snca). In addition to copper-related changes, compensatory upregulations of Cp and Hamp reflect iron-mediated neurotoxicity. Of note, reciprocal expression of Asmt and Bhmt is an important clue that altered S-adenosylhomocysteine metabolism underlies brain injury in WD, which is directly correlated to the decreased expression of S-adenosylhomocysteine hydrolase in hepatic tissue in LEC rats. In conclusion, our study indicates that diverse molecular changes, both variable and complex, underlie the development of neurological manifestations in WD. Copper-related injuries were found to be the principal pathogenic process, but Fe- or adenosylhomocysteine-related injuries were also implicated. Investigations using other animal models or accessible human samples will be required to confirm our observations.
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Affiliation(s)
- Beom Hee Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
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Lutsenko S, Bhattacharjee A, Hubbard AL. Copper handling machinery of the brain. Metallomics 2010; 2:596-608. [DOI: 10.1039/c0mt00006j] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Xiu-Hua J, Shao-Chun L, Bing H, Xiang Z, Jing Z, Wei-Hua L, Qian L, Ting L, Xiao-Ping X, Xi-Gu C. Tyrosinase small interfering RNA effectively suppresses tyrosinase gene expression in vitro and in vivo. Mol Biol Int 2010; 2010:240472. [PMID: 22110954 PMCID: PMC3218303 DOI: 10.4061/2010/240472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 09/01/2010] [Accepted: 09/30/2010] [Indexed: 11/20/2022] Open
Abstract
Tyrosinase is a bifunctional enzyme which oxidizes the initial step of melanin biosynthesis, that is, conversion of tyrosine to dopa and subsequently dopa to dopaquinone. It is a glycosylated protein and a major regulator of melanogenesis. To date, many approaches have been tried to regulate tyrosinase activity and melanin content. To that end, we screened small interfering RNA sequences for sequence-inhibited tyrosinase expression in B16 cells and in C57BL/6 mice. We analyzed tyrosinase mRNA levels by quantitative real-time PCR and determined tyrosinase activity and melanin content at 24, 48, and 72 hours after transfection. Results showed that siNM_011661_001 was the most efficient small interfering RNA sequence in suppressing tyrosinase mRNA expression, and cells transfected with this sequence showed lower tyrosinase activity. Moreover, intravitreous injection of siNM_011661_001 in C57BL/6 mice induced an efficient and stable gene-specific inhibition of expression at the posttranscriptional level.
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Affiliation(s)
- Jia Xiu-Hua
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
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Approaches to prevent dopamine quinone-induced neurotoxicity. Neurochem Res 2008; 34:698-706. [PMID: 18770028 DOI: 10.1007/s11064-008-9843-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2008] [Accepted: 08/22/2008] [Indexed: 10/21/2022]
Abstract
Dopamine (DA) and its metabolites containing two hydroxyl residues exert cytotoxicity in dopaminergic neuronal cells, primarily due to the generation of highly reactive DA and DOPA quinones. Quinone formation is closely linked to other representative hypotheses such as mitochondrial dysfunction, inflammation, oxidative stress, and dysfunction of the ubiquitin-proteasome system, in the pathogenesis of neurodegenerative diseases such as Parkinson's disease and methamphetamine-induced neurotoxicity. Therefore, pathogenic effects of the DA quinone have focused on dopaminergic neuron-specific oxidative stress. Recently, various studies have demonstrated that some intrinsic molecules and several drugs exert protective effects against DA quinone-induced damage of dopaminergic neurons. In this article, we review recent studies on some neuroprotective approaches against DA quinone-induced dysfunction and/or degeneration of dopaminergic neurons.
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Criton M, Le Mellay-Hamon V. Analogues of N-hydroxy-N′-phenylthiourea and N-hydroxy-N′-phenylurea as inhibitors of tyrosinase and melanin formation. Bioorg Med Chem Lett 2008; 18:3607-10. [PMID: 18501598 DOI: 10.1016/j.bmcl.2008.04.079] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 04/29/2008] [Accepted: 04/29/2008] [Indexed: 11/26/2022]
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Thisse C, Thisse B. High-resolution in situ hybridization to whole-mount zebrafish embryos. Nat Protoc 2008; 3:59-69. [PMID: 18193022 DOI: 10.1038/nprot.2007.514] [Citation(s) in RCA: 1929] [Impact Index Per Article: 120.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The in situ hybridization (ISH) technique allows the sites of expression of particular genes to be detected. This protocol describes ISH of digoxigenin-labeled antisense RNA probes to whole-mount zebrafish embryos. In our method, PCR-amplified sequence of a gene of interest is used as a template for the synthesis of an antisense RNA probe, which is labeled with digoxigenin-linked nucleotides. Embryos are fixed and permeabilized before being soaked in the digoxigenin-labeled probe. We use conditions that favor specific hybridization to complementary mRNA sequences in the tissue(s) expressing the corresponding gene. After washing away excess probe, hybrids are detected by immunohistochemistry using an alkaline phosphatase-conjugated antibody against digoxigenin and a chromogenic substrate. The whole procedure takes only 3 days and, because ISH conditions are the same for each probe tested, allows high throughput analysis of zebrafish gene expression during embryogenesis.
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Affiliation(s)
- Christine Thisse
- Department of Cell Biology, University of Virginia Health Sciences Center, PO Box 800732, 1300 Jefferson Park Avenue, Charlottesville, Virginia 22908, USA
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Julien S, Kociok N, Kreppel F, Kopitz J, Kochanek S, Biesemeier A, Blitgen-Heinecke P, Heiduschka P, Schraermeyer U. Tyrosinase biosynthesis and trafficking in adult human retinal pigment epithelial cells. Graefes Arch Clin Exp Ophthalmol 2007; 245:1495-505. [PMID: 17318568 DOI: 10.1007/s00417-007-0543-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 01/15/2007] [Accepted: 01/21/2007] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Tyrosinase (EC 1.14.18.1) is the key enzyme of melanin pigment formation and it is unclear whether it is synthesized in human postnatal retinal pigment epithelium (RPE). In this study, we investigated if phagocytosis of rod outer segments (ROS) can increase tyrosinase expression in vitro. METHODS Primary cultures of human RPE cells were fed with isolated ROS from cattle and with latex particles. After phagocytosis, RPE cells were tested for tyrosinase presence and activity with several independent methods: (1) immunocytochemistry with anti-tyrosinase antibodies and (2) ultrastructural as well as light microscopic DOPA histochemistry; (3) mRNA was isolated from human RPE before incubation with ROS and 5, 20 and 40 h after feeding with ROS. The amount of tyrosinase mRNA was determined quantitatively by real-time reverse transcription polymerase chain reaction (RT-PCR), and the tyrosinase activity was investigated by measuring tyrosine hydroxylase activity using [(3)H]tyrosine. RESULTS Tyrosinase was found in fed RPE cells using these methods, but was absent without feeding. Furthermore, we showed co-localization of rhodopsin and tyrosinase in the fed RPE cells. Contrary to tyrosinase activity, the mRNA for tyrosinase was clearly present in the cultured RPE cells which had not been exposed to ROS, decreased significantly from 5 h after exposure to ROS and returned to its original non-fed level 40 h after ROS feeding. CONCLUSION Our study does not present new evidence that de novo melanogenesis takes place in the adult differentiated RPE. However, in contrast to the classic hypothesis, which states that tyrosinase is only detected in embryos, we provide evidence with several independent methods that the expression of tyrosinase and its enzymatic activity are induced in cultured human adult RPE by phagocytosis of ROS.
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Affiliation(s)
- Sylvie Julien
- Section for Experimental Vitreoretinal Surgery, University Eye Hospital Tuebingen, Tuebingen, Germany.
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Asanuma M, Miyazaki I, Higashi Y, Diaz-Corrales FJ, Shimizu M, Miyoshi K, Ogawa N. Suppression of p53-activated gene, PAG608, attenuates methamphetamine-induced neurotoxicity. Neurosci Lett 2006; 414:263-7. [PMID: 17234339 DOI: 10.1016/j.neulet.2006.12.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 12/19/2006] [Accepted: 12/19/2006] [Indexed: 10/23/2022]
Abstract
The p53-activated gene 608 (PAG608) is a proapoptotic gene activated and regulated by p53 expression in oxidative stress-induced apoptosis of neuronal cells. In this study, we determined the role of PAG608 in methamphetamine-induced neurotoxicity. Treatment of mouse dopaminergic CATH.a cells with 2 mM methamphetamine increased PAG608 expression at 3h followed by increase in phosphorylated p53 expression. Transient transfection of PAG608 antisense cDNA or RNA interference using PAG608 small interfering RNA significantly attenuated the dose-dependent decrease in cell viability of CATH.a cells by methamphetamine (1-4 mM) exposure. In monoaminergic neuronal B65 cells, which contain serotonin rather than dopamine, methamphetamine-induced cell death was also significantly but partially protected by transient transfection of PAG608 antisense cDNA. Furthermore, cell death of PC12 cells produced by methamphetamine (1-5 mM) was almost completely prevented by stable expression of PAG608 antisense cDNA, compared with significant reduction of cell viability in control PC12 cells. Our results showed that suppression of PAG608 using transient and stable transfection with PAG608 antisense cDNA or small interfering RNA attenuates methamphetamine-induced death of various monoaminergic neuronal cells, suggesting that methamphetamine neurotoxicity in monoaminergic cells is related, at least in part, to induction of PAG608 expression.
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Affiliation(s)
- Masato Asanuma
- Department of Brain Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikatacho, Okayama 700-8558, Japan.
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17
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Paz J, Yao H, Lim HS, Lu XY, Zhang W. The neuroprotective role of attractin in neurodegeneration. Neurobiol Aging 2006; 28:1446-56. [PMID: 16860906 DOI: 10.1016/j.neurobiolaging.2006.06.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 06/04/2006] [Accepted: 06/15/2006] [Indexed: 11/21/2022]
Abstract
Loss-of-function mutations of attractin (Atrn) in animals result in age-dependent progressive neurodegeneration including neuronal cell death, hypomyelination and vacuolation. The mechanisms of how age-dependent neurodegeneration occurs in these animals are not clear. In this study, we found that reducing the endogenous expression level of Atrn exacerbated, whereas overexpressing Atrn protected against, the neuronal cell death caused by the neurotoxins, 1-methyl-4-phenylpyridinium (MPP+) and lactacystin. In addition, both MPP+ and lactacystin-induced cytochrome c and apoptosis inducing factor (AIF) release, which was inhibited by overexpressing Atrn and enhanced by knocking down Atrn, indicating that Atrn may be involved in regulating the mitochondrial function. Furthermore, we found that vast majority of the dopaminergic neurons in mice express Atrn and its expression decreases with age. Our findings demonstrated that Atrn may play a protective role against environmental toxins, and implied a potential therapeutic effect of Atrn for neurodegenerative diseases.
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Affiliation(s)
- Jeff Paz
- Department of Pharmacology, Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC6205, San Antonio, TX 78229-3900, USA
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18
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Bonfigli A, Zarivi O, Colafarina S, Cimini AM, Ragnelli AM, Aimola P, Natali PG, Cerù MP, Amicarelli F, Miranda M. Human glioblastoma ADF cells express tyrosinase, L-tyrosine hydroxylase and melanosomes and are sensitive to L-tyrosine and phenylthiourea. J Cell Physiol 2006; 207:675-82. [PMID: 16447258 DOI: 10.1002/jcp.20603] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Melanocytes and neuroblasts share the property of transforming L-tyrosine through two distinct metabolic pathways leading to melanogenesis and catecholamine synthesis, respectively. While tyrosinase (TYR) activity has been shown to be expressed by neuroblastoma it remains to be established as to whether also glioblastomas cells are endowed with this property. We have addressed this issue using the human continuous glioblastoma cell line ADF. We demonstrated that these cells possess tyrosinase as well as L-tyrosine hydroxylase (TH) activity and synthesize melanosomes. Because the two pathways are potentially cyto-genotoxic due to production of quinones, semiquinones, and reactive oxygen species (ROS), we have also investigated the expression of the peroxisomal proliferators activated receptor alpha (PPARalpha) and nuclear factor-kB (NFkB) transcription factor as well the effect of L-tyrosine concentration on cell survival. We report that L-tyrosine down-regulates PPARalpha expression in ADF cells but not neuroblastoma and that this aminoacid and phenylthiourea (PTU) induces apoptosis in glioblastoma and neuroblastoma.
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Affiliation(s)
- Antonella Bonfigli
- Department of Basic and Applied Biology, University of L'Aquila, Via Vetoio, L'Aquila, Italy
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19
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Miyazaki I, Asanuma M, Diaz-Corrales FJ, Fukuda M, Kitaichi K, Miyoshi K, Ogawa N. Methamphetamine‐induced dopaminergic neurotoxicity is regulated by quinone formation‐related molecules. FASEB J 2006; 20:571-3. [PMID: 16403784 DOI: 10.1096/fj.05-4996fje] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recently, the neurotoxicity of dopamine (DA) quinone formation by auto-oxidation of DA has focused on dopaminergic neuron-specific oxidative stress. In the present study, we examined DA quinone formation in methamphetamine (METH)-induced dopaminergic neuronal cell death using METH-treated dopaminergic cultured CATH.a cells and METH-injected mouse brain. In CATH.a cells, METH treatment dose-dependently increased the levels of quinoprotein (protein-bound quinone) and the expression of quinone reductase in parallel with neurotoxicity. A similar increase in quinoprotein levels was seen in the striatum of METH (4 mg/kg X4, i.p., 2 h interval)-injected BALB/c mice, coinciding with reduction of DA transporters. Furthermore, pretreatment of CATH.a cells with quinone reductase inducer, butylated hydroxyanisole, significantly and dose-dependently blocked METH-induced elevation of quinoprotein, and ameliorated METH-induced cell death. We also showed the protective effect of tyrosinase, which rapidly oxidizes DA and DA quinone to form stable melanin, against METH-induced dopaminergic neurotoxicity in vitro and in vivo using tyrosinase null mice. Our results indicate that DA quinone formation plays an important role, as a dopaminergic neuron-specific neurotoxic factor, in METH-induced neurotoxicity, which is regulated by quinone formation-related molecules.
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Affiliation(s)
- Ikuko Miyazaki
- Department of Brain Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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20
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Machida Y, Chiba T, Takayanagi A, Tanaka Y, Asanuma M, Ogawa N, Koyama A, Iwatsubo T, Ito S, Jansen PH, Shimizu N, Tanaka K, Mizuno Y, Hattori N. Common anti-apoptotic roles of parkin and α-synuclein in human dopaminergic cells. Biochem Biophys Res Commun 2005; 332:233-40. [PMID: 15896322 DOI: 10.1016/j.bbrc.2005.04.124] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2005] [Accepted: 04/20/2005] [Indexed: 11/21/2022]
Abstract
Parkin, a product of the gene responsible for autosomal recessive juvenile parkinsonism (AR-JP), is an important player in the pathogenic process of Parkinson's disease (PD). Despite numerous studies including search for the substrate of parkin as an E3 ubiquitin-protein ligase, the mechanism by which loss-of-function of parkin induces selective dopaminergic neuronal death remains unclear. Related to this issue, here we show that antisense knockdown of parkin causes apoptotic cell death of human dopaminergic SH-SY5Y cells associated with caspase activation and accompanied by accumulation of oxidative dopamine (DA) metabolites due to auto-oxidation of DOPA and DA. Forced expression of alpha-synuclein (alpha-SN), another familial PD gene product, prevented accumulation of oxidative DOPA/DA metabolites and cell death caused by parkin loss. Our findings indicate that both parkin and alpha-SN share a common pathway in DA metabolism whose abnormality leads to accumulation of oxidative DA metabolites and subsequent cell death.
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Affiliation(s)
- Yutaka Machida
- Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
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21
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Greggio E, Bergantino E, Carter D, Ahmad R, Costin GE, Hearing VJ, Clarimon J, Singleton A, Eerola J, Hellström O, Tienari PJ, Miller DW, Beilina A, Bubacco L, Cookson MR. Tyrosinase exacerbates dopamine toxicity but is not genetically associated with Parkinson's disease. J Neurochem 2005; 93:246-56. [PMID: 15773923 DOI: 10.1111/j.1471-4159.2005.03019.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Tyrosinase is a key enzyme in the synthesis of melanin in skin and hair and has also been proposed to contribute to the formation of neuromelanin (NM). The presence of NM, which is biochemically similar to melanin in peripheral tissues, identifies groups of neurons susceptible in Parkinson's disease (PD). Whether tyrosinase is beneficial or detrimental to neurons is unclear; whilst the enzyme activity of tyrosinase generates dopamine-quinones and other oxidizing compounds, NM may form a sink for such radical species. In the present study, we demonstrated that tyrosinase is expressed at low levels in the human brain. We found that mRNA, protein and enzyme activity are all present but at barely detectable levels. In cell culture systems, expression of tyrosinase increases neuronal susceptibility to oxidizing conditions, including dopamine itself. We related these in vitro observations to the human disease by assessing whether there was any genetic association between the gene encoding tyrosinase and idiopathic PD. We found neither genotypic or haplotypic association with three polymorphic markers of the gene. This argues against a strong genetic association between tyrosinase and PD, although the observed contribution to cellular toxicity suggests that a biochemical association is likely.
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Affiliation(s)
- Elisa Greggio
- Department of Biology, University of Padova, Padova, Italy.
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22
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Slominski A, Tobin DJ, Shibahara S, Wortsman J. Melanin pigmentation in mammalian skin and its hormonal regulation. Physiol Rev 2004; 84:1155-228. [PMID: 15383650 DOI: 10.1152/physrev.00044.2003] [Citation(s) in RCA: 1355] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cutaneous melanin pigment plays a critical role in camouflage, mimicry, social communication, and protection against harmful effects of solar radiation. Melanogenesis is under complex regulatory control by multiple agents interacting via pathways activated by receptor-dependent and -independent mechanisms, in hormonal, auto-, para-, or intracrine fashion. Because of the multidirectional nature and heterogeneous character of the melanogenesis modifying agents, its controlling factors are not organized into simple linear sequences, but they interphase instead in a multidimensional network, with extensive functional overlapping with connections arranged both in series and in parallel. The most important positive regulator of melanogenesis is the MC1 receptor with its ligands melanocortins and ACTH, whereas among the negative regulators agouti protein stands out, determining intensity of melanogenesis and also the type of melanin synthesized. Within the context of the skin as a stress organ, melanogenic activity serves as a unique molecular sensor and transducer of noxious signals and as regulator of local homeostasis. In keeping with these multiple roles, melanogenesis is controlled by a highly structured system, active since early embryogenesis and capable of superselective functional regulation that may reach down to the cellular level represented by single melanocytes. Indeed, the significance of melanogenesis extends beyond the mere assignment of a color trait.
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Affiliation(s)
- Andrzej Slominski
- Dept. of Pathology, Suite 599, University of Tennessee Health Science Center, 930 Madison Avenue, Memphis, TN 38163, USA.
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23
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Higashi Y, Asanuma M, Miyazaki I, Hattori N, Mizuno Y, Ogawa N. Parkin attenuates manganese-induced dopaminergic cell death. J Neurochem 2004; 89:1490-7. [PMID: 15189352 DOI: 10.1111/j.1471-4159.2004.02445.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Manganese as environmental factor is considered to cause parkinsonism and induce endoplasmic reticulum stress-mediated dopaminergic cell death. We examined the effects of manganese on parkin, identified as the gene responsible for familial Parkinson's disease, and the role of parkin in manganese-induced neuronal cell death. Manganese dose-dependently induced cell death of dopaminergic SH-SY5Y and CATH.a cells and cholinergic Neuro-2a cells, and that the former two cell types were more sensitive to manganese toxicity than Neuro-2a cells. Moreover, manganese increased the expression of endoplasmic reticulum stress-associated genes, including parkin, in SH-SY5Y cells and CATH.a cells, but not in Neuro-2a cells. Treatment with manganese resulted in accumulation of parkin protein in SH-SY5Y cells and its redistribution to the perinuclear region, especially aggregated Golgi complex, while in Neuro-2a cells neither expression nor redistribution of parkin was noted. Manganese showed no changes in proteasome activities in either cell. Transient transfection of parkin gene inhibited manganese- or manganese plus dopamine-induced cell death of SH-SY5Y cells, but not of Neuro-2a cells. Our results suggest that the attenuating effects of parkin against manganese- or manganese plus dopamine-induced cell death are dopaminergic cell-specific compensatory reactions associated with its accumulation and redistribution to perinuclear regions but not with proteasome system.
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Affiliation(s)
- Youichirou Higashi
- Department of Brain Science, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
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24
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Hasegawa T, Matsuzaki M, Takeda A, Kikuchi A, Furukawa K, Shibahara S, Itoyama Y. Increased dopamine and its metabolites in SH-SY5Y neuroblastoma cells that express tyrosinase. J Neurochem 2003; 87:470-5. [PMID: 14511124 DOI: 10.1046/j.1471-4159.2003.02008.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Oxidized metabolites of dopamine, known as dopamine quinone derivatives, are thought to play a pivotal role in the degeneration of dopaminergic neurons. Although such quinone derivatives are usually produced via the autoxidation of catecholamines, tyrosinase, which is a key enzyme in melanin biosynthesis via the production of DOPA and subsequent molecules, may potentially accelerate the induction of catecholamine quinone derivatives by its oxidase activity. In the present study, we developed neuronal cell lines in which the expression of human tyrosinase was inducible. Overexpression of tyrosinase in cultured cell lines resulted in (i) increased intracellular dopamine content; (ii) induction of oxidase activity not only for DOPA but also for dopamine; (iii) formation of melanin pigments in cell soma; and (iv) increased intracellular reactive oxygen species. Interestingly, the expressed tyrosinase protein was initially distributed in the entire cytoplasm and then accumulated to form catecholamine-positive granular structures by 3 days after the induction. The granular structures consisted of numerous rounded, dark bodies of melanin pigments and were largely coincident with the distribution of lysosomes. This cellular model that exhibits increased dopamine production will provide a useful tool for detailed analyses of the potentially noxious effects of oxidized catecholamine metabolites.
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Affiliation(s)
- Takafumi Hasegawa
- Department of Neurology, Tohoku University School of Medicine, Sendai, Miyaga, Japan
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25
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Lee CS, Song EH, Park SY, Han ES. Combined effect of dopamine and MPP+ on membrane permeability in mitochondria and cell viability in PC12 cells. Neurochem Int 2003; 43:147-54. [PMID: 12620283 DOI: 10.1016/s0197-0186(02)00214-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study examined the combined effect of dopamine and 1-methyl-4-phenylpyridinium (MPP(+)) on the membrane permeability in isolated brain mitochondria and on cell viability in PC12 cells. MPP(+) increased effect of dopamine against the swelling, membrane potential, and Ca(2+) transport in isolated mitochondria, which was not inhibited by the addition of antioxidant enzymes (SOD and catalase). Dopamine or MPP(+) caused the decrease in transmembrane potential, increase in reactive oxygen species, depletion of GSH, and cell death in PC12 cells. Antioxidant enzymes reduced each effect of dopamine and MPP(+) against PC12 cells. Co-addition of dopamine and MPP(+) caused the decrease in the transmembrane potential and increase in the formation of reactive oxygen species in PC12 cells, in which they showed an additive effect. Dopamine plus MPP(+)-induced the depletion of GSH and cell death in PC12 cells were not decreased by the addition of antioxidant enzymes, rutin, diethylstilbestrol, and ascorbate. Melanin caused a cell viability loss in PC12 cells. The N-acetylcysteine, N-phenylthiourea, and 5-hydroxyindole decreased the cell death and the formation of dopamine quinone and melanin induced by co-addition of dopamine and MPP(+), whereas deprenyl and chlorgyline did not show an inhibitory effect. The results suggest that co-addition of dopamine and MPP(+) shows an enhancing effect on the change in mitochondrial membrane permeability and cell death, which may be accomplished by toxic quinone and melanin derived from the MPP(+)-stimulated dopamine oxidation.
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Affiliation(s)
- Chung Soo Lee
- Department of Pharmacology, College of Medicine, Chung-Ang University, 156-756, Seoul, South Korea.
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26
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Emdadul Haque M, Asanuma M, Higashi Y, Miyazaki I, Tanaka KI, Ogawa N. Apoptosis-inducing neurotoxicity of dopamine and its metabolites via reactive quinone generation in neuroblastoma cells. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1619:39-52. [PMID: 12495814 DOI: 10.1016/s0304-4165(02)00440-3] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Neurotoxic properties of L-dopa and dopamine (DA)-related compounds were assessed in human neuroblastoma SH-SY5Y cells with reference to their structural relationship. L-Dopa and its metabolites containing two free hydroxyl residues on their benzene ring showed toxicity in the cell, which was prevented by superoxide dismutase (SOD) and reduced glutathione (GSH), but not by catalase. Furthermore, a synthetic derivative of DA, 3-hydroxy-4-methoxyphenethylamine (HMPE) containing methoxy residue at position 4 in the benzene ring, exerted partial cytotoxicity, which was not prevented by SOD, GSH or catalase. However, the metabolites containing methoxy residue at position 3 failed to show a toxic effect in the SH-SY5Y cells. Moreover, DA induced apoptotic cell death, which was observed by nuclear and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining and measurement of caspase-3 activity; this compound up-regulated apoptotic factor p53 while down-regulating anti-apoptotic factor Bcl-2. In the cell-free in vitro electron spin resonance (ESR) spectrometry, DA possessing two hydroxyl groups showed generation of DA-semiquinone radicals, which were markedly prevented by addition of SOD or GSH but not by catalase. On the other hand, methylation of one of the hydroxyl residues on the benzene ring of DA converted DA to an unoxidizable compound (3-MT or HMPE), and caused it to lose the property to produce semiquinone radicals. It has been previously reported that SOD acting as a superoxide:semiquinone oxidoreductase prevents quinone formation, and that reduced GSH through forming a complex with DA-quinone prevents quinone binding to the thiol group of the intact protein. Therefore, the present results suggest that DA and its metabolites containing two hydroxyl residues exert cytotoxicity mainly due to generation of highly reactive quinones.
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Affiliation(s)
- M Emdadul Haque
- Department of Brain Science, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan
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27
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Asanuma M, Miyazaki I, Ogawa N. Dopamine- or L-DOPA-induced neurotoxicity: the role of dopamine quinone formation and tyrosinase in a model of Parkinson's disease. Neurotox Res 2003; 5:165-76. [PMID: 12835121 DOI: 10.1007/bf03033137] [Citation(s) in RCA: 379] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Dopamine (DA)- or L-dihydroxyphenylalanine-(L-DOPA-) induced neurotoxicity is thought to be involved not only in adverse reactions induced by long-term L-DOPA therapy but also in the pathogenesis of Parkinson's disease. Numerous in vitro and in vivo studies concerning DA- or L-DOPA-induced neurotoxicity have been reported in recent decades. The reactive oxygen or nitrogen species generated in the enzymatical oxidation or auto-oxidation of an excess amount of DA induce neuronal damage and/or apoptotic or non-apoptotic cell death; the DA-induced damage is prevented by various intrinsic and extrinsic antioxidants. DA and its metabolites containing two hydroxyl residues exert cytotoxicity in dopaminergic neuronal cells mainly due to the generation of highly reactive DA and DOPA quinones which are dopaminergic neuron-specific cytotoxic molecules. DA and DOPA quinones may irreversibly alter protein function through the formation of 5-cysteinyl-catechols on the proteins. For example, the formation of DA quinone-alpha-synuclein consequently increases cytotoxic protofibrils and the covalent modification of tyrosine hydroxylase by DA quinones. The melanin-synthetic enzyme tyrosinase in the brain may rapidly oxidize excess amounts of cytosolic DA and L-DOPA, thereby preventing slowly progressive cell damage by auto-oxidation of DA, thus maintainng DA levels. Since tyrosinase also possesses catecholamine-synthesizing activity in the absence of tyrosine hydroxylase (TH), the double-edged synthesizing and oxidizing functions of tyrosinase in the dopaminergic system suggest its potential for application in the synthesis of DA, instead of TH in the degeneration of dopaminergic neurons, and in the normalization of abnormal DA turnover in the long-term L-DOPA-treated Parkinson's disease patients.
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Affiliation(s)
- Masato Asanuma
- Department of Brain Science, Okayama University Graduate School of Medicine and Dentistry, Okayama 700-8558, Japan.
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28
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Higashi Y, Asanuma M, Miyazaki I, Haque ME, Fujita N, Tanaka KI, Ogawa N. The p53-activated gene, PAG608, requires a zinc finger domain for nuclear localization and oxidative stress-induced apoptosis. J Biol Chem 2002; 277:42224-32. [PMID: 12196512 DOI: 10.1074/jbc.m203594200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The p53-activated gene PAG608, which encodes a nuclear zinc finger protein, is a p53-inducible gene that contributes to p53-mediated apoptosis. However, the mechanisms by which PAG608 is involved in the apoptosis of neuronal cells are still obscure. In this study, we demonstrated that expression of p53 was induced by 100 microm 6-hydroxydopamine (6-OHDA), accompanied by increased PAG608 expression in PC12 cells. On the other hand, transient or permanent transfection of antisense PAG608 cDNA into PC12 cells significantly prevented apoptotic cell death induced by 100 microm 6-OHDA or 200 microm hydrogen peroxide but not by 250 microm 1-methyl-4-phenylpyridinium ion. The 6-OHDA-induced activation of caspase-3, DNA fragmentation, loss of mitochondrial membrane potential, and induction of p53 and Bax were also prevented in PC12 cells that stably expressed antisense PAG608 cDNA. These results suggest that PAG608 is associated with the apoptotic pathway induced by these oxidative stress-generating reagents, upstream of the collapse in the mitochondrial membrane potential in PC12 cells. Interestingly, transient transfection with PAG608 cDNA increased p53 expression in both PC12 cells and B65 cells, indicating that PAG608 induced by p53 is able to induce p53 expression in these cells inversely. Furthermore, transient transfection of a truncated mutant PAG608 cDNA, lacking the first zinc finger domain, inhibited 6-OHDA-induced cell death and altered the nuclear and nucleolar localization of wild-type PAG608 in PC12 cells. These results suggest that PAG608 may induce or regulate p53 expression and translocate to the nucleus and nucleolus using its first zinc finger domain during oxidative stress-induced apoptosis of catecholamine-containing cells.
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Affiliation(s)
- Youichirou Higashi
- Department of Brain Science, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikatacho, Japan
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29
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Tepper AWJW, Bubacco L, Canters GW. Structural basis and mechanism of the inhibition of the type-3 copper protein tyrosinase from Streptomyces antibioticus by halide ions. J Biol Chem 2002; 277:30436-44. [PMID: 12048185 DOI: 10.1074/jbc.m202461200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inhibition of the type-3 copper enzyme tyrosinase by halide ions was studied by kinetic and paramagnetic (1)H NMR methods. All halides are inhibitors in the conversion of l-3,4-dihydroxyphenylalanine (l-DOPA) with apparent inhibition constants that follow the order I(-) < F(-) << Cl(-) < Br(-) at pH 6.80. The results show that the inhibition arises from the interaction of halide with both the oxidized (affinity F(-) > Cl(-) > Br(-) >> I(-)) and reduced (affinity I(-) > Br(-) > Cl(-) >> F(-)) enzyme. The paramagnetic (1)H NMR of the oxidized enzyme complexed with the halides is consistent with a direct interaction of halide with the type-3 site and shows that the (Cu-His(3))(2) coordination occurs in all halide-bound species. It is surmised that halides bridge both of the copper ions in the active site. Fluoride and chloride are shown to bind only to the low pH form of oxidized tyrosinase, explaining the strong pH dependence of the inhibition by these ions. We further show that p-toluic acid and the bidentate transition state analogue, Kojic acid, displace chloride from the oxidized active site, whereas the monodentate substrate analogue, p-nitrophenol, forms a ternary complex with the enzyme and the chloride ion. On the basis of the experimental results, a model is formulated for the inhibitor action and for the reaction of diphenols with the oxidized enzyme.
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Affiliation(s)
- Armand W J W Tepper
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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30
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Morris JG, Yu S, Rogers QR. Red hair in black cats is reversed by addition of tyrosine to the diet. J Nutr 2002; 132:1646S-8S. [PMID: 12042480 DOI: 10.1093/jn/132.6.1646s] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- James G Morris
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
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