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Gezen-Ak D, Yurttaş Z, Çamoǧlu T, Dursun E. Could Amyloid-β 1-42 or α-Synuclein Interact Directly with Mitochondrial DNA? A Hypothesis. ACS Chem Neurosci 2022; 13:2803-2812. [PMID: 36125124 PMCID: PMC9542719 DOI: 10.1021/acschemneuro.2c00512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The amyloid β (Aβ) and the α-synuclein (α-syn) are shown to be translocated into mitochondria. Even though their roles are widely investigated in pathological conditions, information on the presence and functions of Aβ and α-syn in mitochondria in endogenous levels is somewhat limited. We hypothesized that endogenous Aβ fragments or α-syn could interact with mitochondrial DNA (mtDNA) directly or influence RNAs or transcription factors in mitochondria and change the mtDNA transcription profile. In this review, we summarized clues of these possible interactions.
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Affiliation(s)
| | | | | | - Erdinç Dursun
- E.D.: email, ; phone, +90 212 414 30 00/68025, +90 533 339
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Santos PI, Outeiro TF. Protein trapping leads to altered synaptic proteostasis in synucleinopathies. FEBS J 2020; 287:5294-5303. [PMID: 32400966 DOI: 10.1111/febs.15364] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/01/2020] [Accepted: 05/07/2020] [Indexed: 12/13/2022]
Abstract
Parkinson's disease (PD) is associated with the accumulation of alpha-synuclein (aSyn) in intracellular inclusions known as Lewy bodies and Lewy neurites. Under physiological conditions, aSyn is found at the presynaptic terminal and exists in a dynamic equilibrium between soluble, membrane-associated and aggregated forms. Emerging evidence suggests that, under pathological conditions, aSyn begins to accumulate and acquire a toxic function at the synapse, impairing their normal function and connectivity. However, the precise molecular mechanisms linking aSyn accumulation and synaptic dysfunction are still elusive. Here, we provide an overview of our current findings and discuss the hypothesis that certain aSyn aggregates may interact with proteins with whom aSyn normally does not interact with, thereby trapping them and preventing them from performing their normal functions in the cell. We posit that such abnormal interactions start to occur during the prodromal stages of PD, eventually resulting in the overt manifestation of clinical features. Therefore, understanding the nature and behaviour of toxic aSyn species and their contribution to aSyn-mediated toxicity is crucial for the development of therapeutic strategies capable of modifying disease progression in PD and other synucleinopathies.
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Affiliation(s)
- Patrícia I Santos
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
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Ravanidis S, Bougea A, Papagiannakis N, Maniati M, Koros C, Simitsi AM, Bozi M, Pachi I, Stamelou M, Paraskevas GP, Kapaki E, Moraitou M, Michelakakis H, Stefanis L, Doxakis E. Circulating Brain-enriched MicroRNAs for detection and discrimination of idiopathic and genetic Parkinson's disease. Mov Disord 2019; 35:457-467. [PMID: 31799764 DOI: 10.1002/mds.27928] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/13/2019] [Accepted: 10/30/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND A minimally invasive test for early detection and monitoring of Parkinson's disease (PD) is a highly unmet need for drug development and planning of patient care. Blood plasma represents an attractive source of biomarkers. MicroRNAs (miRNAs) are conserved noncoding RNA molecules that serve as posttranscriptional regulators of gene expression. As opposed to ubiquitously expressed miRNAs that control house-keeping processes, brain-enriched miRNAs regulate diverse aspects of neuron development and function. These include neuron-subtype specification, axonal growth, dendritic morphogenesis, and spine density. Backed by a large number of studies, we now know that the differential expression of neuron-enriched miRNAs leads to brain dysfunction. OBJECTIVES The aim was to identify subsets of brain-enriched miRNAs with diagnostic potential for familial and idiopathic PD as well as specify the molecular pathways deregulated in PD. METHODS Initially, brain-enriched miRNAs were selected based on literature review and validation studies in human tissues. Subsequently, real-time reverse transcription polymerase chain reaction was performed in the plasma of 100 healthy controls and 99 idiopathic and 53 genetic (26 alpha-synucleinA53T and 27 glucocerebrosidase) patients. Statistical and bioinformatics analyses were carried out to pinpoint the diagnostic biomarkers and deregulated pathways, respectively. RESULTS An explicit molecular fingerprint for each of the 3 PD cohorts was generated. Although the idiopathic PD fingerprint was different from that of genetic PD, the molecular pathways deregulated converged between all PD subtypes. CONCLUSIONS The study provides a group of brain-enriched miRNAs that may be used for the detection and differentiation of PD subtypes. It has also identified the molecular pathways deregulated in PD. © 2019 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Stylianos Ravanidis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Anastasia Bougea
- Center of Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece
| | - Nikolaos Papagiannakis
- Center of Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece
| | - Matina Maniati
- Center of Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Christos Koros
- 1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece.,2nd Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Athina-Maria Simitsi
- 1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece
| | - Maria Bozi
- 2nd Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Ioanna Pachi
- 1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece
| | - Maria Stamelou
- 1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece.,Parkinson's disease and Movement disorders department, HYGEIA Hospital, Athens, Greece
| | - George P Paraskevas
- 1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece
| | - Elisabeth Kapaki
- 1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece
| | - Marina Moraitou
- Department of Enzymology and Cellular Function, Institute of Child Health, Athens, Greece
| | - Helen Michelakakis
- Department of Enzymology and Cellular Function, Institute of Child Health, Athens, Greece
| | - Leonidas Stefanis
- Center of Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,1st Department of Neurology, National and Kapodistrian University of Athens Medical School, Eginition Hospital, Athens, Greece
| | - Epaminondas Doxakis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
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Motyl J, Wencel PL, Cieślik M, Strosznajder RP, Strosznajder JB. Alpha-synuclein alters differently gene expression of Sirts, PARPs and other stress response proteins: implications for neurodegenerative disorders. Mol Neurobiol 2018; 55:727-740. [PMID: 28050792 PMCID: PMC5808059 DOI: 10.1007/s12035-016-0317-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/21/2016] [Indexed: 02/06/2023]
Abstract
Alpha-synuclein (ASN) is a presynaptic protein that can easily change its conformation under different types of stress. It's assumed that ASN plays an important role in the pathogenesis of Parkinson's and Alzheimer's disease. However, the molecular mechanism of ASN toxicity has not been elucidated. This study focused on the role of extracellular ASN (eASN) in regulation of transcription of sirtuins (Sirts) and DNA-bound poly(ADP-ribose) polymerases (PARPs) - proteins crucial for cells' survival/death. Our results indicate that eASN enhanced the free radicals level, decreased mitochondria membrane potential, cells viability and activated cells' death. Concomitantly eASN activated expression of antioxidative proteins (Sod2, Gpx4, Gadd45b) and DNA-bound Parp2 and Parp3. Moreover, eASN upregulated expression of Sirt3 and Sirt5, but downregulated of Sirt1, which plays an important role in cell metabolism including Aβ precursor protein (APP) processing. eASN downregulated gene expression of APP alpha secretase (Adam10) and metalloproteinases Mmp2, Mmp10 but upregulated Mmp11. Additionally, expression and activity of pro-survival sphingosine kinase 1 (Sphk1), Akt kinase and anti-apoptotic protein Bcl2 were inhibited. Moreover, higher expression of pro-apoptotic protein Bax and enhancement of apoptotic cells' death were observed. Summarizing, eASN significantly modulates transcription of Sirts and enzymes involved in APP/Aβ metabolism and through these mechanisms eASN toxicity may be enhanced. The inhibition of Sphk1 and Akt by eASN may lead to disturbances of survival pathways. These results suggest that eASN through alteration of transcription and by inhibition of pro-survival kinases may play important pathogenic role in neurodegenerative disorders.
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Affiliation(s)
- J Motyl
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Street, Warsaw, Poland
| | - P L Wencel
- Laboratory of Preclinical Research and Environmental Agents, Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Street, 02-106, Warsaw, Poland
| | - M Cieślik
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Street, Warsaw, Poland
| | - R P Strosznajder
- Laboratory of Preclinical Research and Environmental Agents, Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Street, 02-106, Warsaw, Poland.
| | - J B Strosznajder
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Street, Warsaw, Poland
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Sidhu A, Wersinger C, Vernier P. Does alpha-synuclein modulate dopaminergic synaptic content and tone at the synapse? FASEB J 2004; 18:637-47. [PMID: 15054086 DOI: 10.1096/fj.03-1112rev] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
alpha-Synuclein is a key component of the pathological process of neurodegeneration in Parkinson's disease. Although its contributions to normal physiological conditions remain elusive, converging observations suggest that a primary function of this protein in dopaminergic neurons may be the regulation of dopamine content and synaptic tone at the synapse. We review here cumulative evidence that demonstrates the participation of alpha-synuclein in the life cycle of dopamine from its synthesis, storage, release, and reuptake. The regulatory role of alpha-synuclein on dopamine metabolism is assessed by discussing the experimental evidence supporting each of these observations in the healthy physiological maintenance of dopaminergic neurons, as well as showing how disruption of these events can initiate the observed neurotoxicity of alpha-synuclein and the genesis of the degenerative processes associated with Parkinson's disease.
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Affiliation(s)
- Anita Sidhu
- Department of Pediatrics, Georgetown University, Washington, DC, USA.
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