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Kinnart I, Manders L, Heyninck T, Imberechts D, Praschberger R, Schoovaerts N, Verfaillie C, Verstreken P, Vandenberghe W. Elevated α-synuclein levels inhibit mitophagic flux. NPJ Parkinsons Dis 2024; 10:80. [PMID: 38594264 PMCID: PMC11004019 DOI: 10.1038/s41531-024-00696-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 03/26/2024] [Indexed: 04/11/2024] Open
Abstract
The pathogenic effect of SNCA gene multiplications indicates that elevation of wild-type α-synuclein levels is sufficient to cause Parkinson's disease (PD). Mitochondria have been proposed to be a major target of α-synuclein-induced damage. PINK1/parkin/DJ-1-mediated mitophagy is a defense strategy that allows cells to selectively eliminate severely damaged mitochondria. Here, we quantified mitophagic flux and non-mitochondrial autophagic flux in three models of increased α-synuclein expression: 1/Drosophila melanogaster that transgenically express human wild-type and mutant α-synuclein in flight muscle; 2/human skin fibroblasts transfected with α-synuclein or β-synuclein; and 3/human induced pluripotent stem cell (iPSC)-derived neurons carrying an extra copy of wild-type SNCA under control of a doxycycline-inducible promoter, allowing titratable α-synuclein upregulation. In each model, elevated α-synuclein levels potently suppressed mitophagic flux, while non-mitochondrial autophagy was preserved. In human neurons, a twofold increase in wild-type α-synuclein was already sufficient to induce this effect. PINK1 and parkin activation and mitochondrial translocation of DJ-1 after mitochondrial depolarization were not affected by α-synuclein upregulation. Overexpression of the actin-severing protein cofilin or treatment with CK666, an inhibitor of the actin-related protein 2/3 (Arp2/3) complex, rescued mitophagy in neurons with increased α-synuclein, suggesting that excessive actin network stabilization mediated the mitophagy defect. In conclusion, elevated α-synuclein levels inhibit mitophagic flux. Disruption of actin dynamics may play a key role in this effect.
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Affiliation(s)
- Inge Kinnart
- Department of Neurosciences, Laboratory for Parkinson Research, KU Leuven, Leuven, Belgium
| | - Liselot Manders
- Department of Neurosciences, Laboratory for Parkinson Research, KU Leuven, Leuven, Belgium
| | - Thibaut Heyninck
- Department of Neurosciences, Laboratory for Parkinson Research, KU Leuven, Leuven, Belgium
| | - Dorien Imberechts
- Department of Neurosciences, Laboratory for Parkinson Research, KU Leuven, Leuven, Belgium
| | - Roman Praschberger
- Department of Neurosciences, Laboratory for Neuronal Communication, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
| | - Nils Schoovaerts
- Department of Neurosciences, Laboratory for Neuronal Communication, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
| | | | - Patrik Verstreken
- Department of Neurosciences, Laboratory for Neuronal Communication, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
| | - Wim Vandenberghe
- Department of Neurosciences, Laboratory for Parkinson Research, KU Leuven, Leuven, Belgium.
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium.
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Imberechts D, Kinnart I, Wauters F, Terbeek J, Manders L, Wierda K, Eggermont K, Madeiro RF, Sue C, Verfaillie C, Vandenberghe W. DJ-1 is an essential downstream mediator in PINK1/parkin-dependent mitophagy. Brain 2022; 145:4368-4384. [PMID: 36039535 PMCID: PMC9762950 DOI: 10.1093/brain/awac313] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 07/19/2022] [Accepted: 08/14/2022] [Indexed: 01/19/2023] Open
Abstract
Loss-of-function mutations in the PRKN, PINK1 and PARK7 genes (encoding parkin, PINK1 and DJ-1, respectively) cause autosomal recessive forms of Parkinson's disease. PINK1 and parkin jointly mediate selective autophagy of damaged mitochondria (mitophagy), but the mechanisms by which loss of DJ-1 induces Parkinson's disease are not well understood. Here, we investigated PINK1/parkin-mediated mitophagy in cultured human fibroblasts and induced pluripotent stem cell-derived neurons with homozygous PARK7 mutations. We found that DJ-1 is essential for PINK1/parkin-mediated mitophagy. Loss of DJ-1 did not interfere with PINK1 or parkin activation after mitochondrial depolarization but blocked mitophagy further downstream by inhibiting recruitment of the selective autophagy receptor optineurin to depolarized mitochondria. By contrast, starvation-induced, non-selective autophagy was not affected by loss of DJ-1. In wild-type fibroblasts and induced pluripotent stem cell-derived dopaminergic neurons, endogenous DJ-1 translocated to depolarized mitochondria in close proximity to optineurin. DJ-1 translocation to depolarized mitochondria was dependent on PINK1 and parkin and did not require oxidation of cysteine residue 106 of DJ-1. Overexpression of DJ-1 did not rescue the mitophagy defect of PINK1- or parkin-deficient cells. These findings position DJ-1 downstream of PINK1 and parkin in the same pathway and suggest that disruption of PINK1/parkin/DJ-1-mediated mitophagy is a common pathogenic mechanism in autosomal recessive Parkinson's disease.
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Affiliation(s)
| | - Inge Kinnart
- Laboratory for Parkinson Research, KU Leuven, 3000
Leuven, Belgium
| | - Fieke Wauters
- Laboratory for Parkinson Research, KU Leuven, 3000
Leuven, Belgium
| | - Joanne Terbeek
- Laboratory for Parkinson Research, KU Leuven, 3000
Leuven, Belgium
| | - Liselot Manders
- Laboratory for Parkinson Research, KU Leuven, 3000
Leuven, Belgium
| | - Keimpe Wierda
- Electrophysiology Expertise Unit, VIB-KU Leuven Center for Brain and
Disease Research, 3000 Leuven, Belgium
| | - Kristel Eggermont
- Stem Cell and Developmental Biology, KU Leuven,
3000 Leuven, Belgium
| | | | - Carolyn Sue
- Department of Neurogenetics, Kolling Institute of Medical Research, Royal
North Shore Hospital and University of Sydney, St. Leonards
2065, Australia
| | | | - Wim Vandenberghe
- Correspondence to: Wim Vandenberghe Department of Neurology,
University Hospitals Leuven Herestraat 49, 3000 Leuven, Belgium E-mail:
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Terbeek J, Martin S, Imberechts D, Kinnart I, Vangheluwe P, Nicholl D, Vandenberghe W. Increased superoxide in GCH1 mutant fibroblasts points to a dopamine-independent toxicity mechanism. Parkinsonism Relat Disord 2020; 82:10-12. [PMID: 33221620 DOI: 10.1016/j.parkreldis.2020.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 11/03/2020] [Accepted: 11/11/2020] [Indexed: 11/18/2022]
Affiliation(s)
- Joanne Terbeek
- Laboratory for Parkinson Research, Department of Neurosciences, KU Leuven, 3000, Leuven, Belgium
| | - Shaun Martin
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Dorien Imberechts
- Laboratory for Parkinson Research, Department of Neurosciences, KU Leuven, 3000, Leuven, Belgium
| | - Inge Kinnart
- Laboratory for Parkinson Research, Department of Neurosciences, KU Leuven, 3000, Leuven, Belgium
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - David Nicholl
- Department of Neurology, University Hospitals Birmingham NHS Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK
| | - Wim Vandenberghe
- Laboratory for Parkinson Research, Department of Neurosciences, KU Leuven, 3000, Leuven, Belgium; Department of Neurology, University Hospitals Leuven, 3000, Leuven, Belgium.
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