1
|
Onal G, Yalçın-Çakmaklı G, Özçelik CE, Boussaad I, Şeker UÖŞ, Fernandes HJR, Demir H, Krüger R, Elibol B, Dökmeci S, Salman MM. Variant-specific effects of GBA1 mutations on dopaminergic neuron proteostasis. J Neurochem 2024. [PMID: 38641924 DOI: 10.1111/jnc.16114] [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: 10/31/2023] [Revised: 03/26/2024] [Accepted: 04/05/2024] [Indexed: 04/21/2024]
Abstract
Glucocerebrosidase 1 (GBA1) mutations are the most important genetic risk factors for Parkinson's disease (PD). Clinically, mild (e.g., p.N370S) and severe (e.g., p.L444P and p.D409H) GBA1 mutations have different PD phenotypes, with differences in age at disease onset, progression, and the severity of motor and non-motor symptoms. We hypothesize that GBA1 mutations cause the accumulation of α-synuclein by affecting the cross-talk between cellular protein degradation mechanisms, leading to neurodegeneration. Accordingly, we tested whether mild and severe GBA1 mutations differentially affect the degradation of α-synuclein via the ubiquitin-proteasome system (UPS), chaperone-mediated autophagy (CMA), and macroautophagy and differentially cause accumulation and/or release of α-synuclein. Our results demonstrate that endoplasmic reticulum (ER) stress and total ubiquitination rates were significantly increased in cells with severe GBA1 mutations. CMA was found to be defective in induced pluripotent stem cell (iPSC)-derived dopaminergic neurons with mild GBA1 mutations, but not in those with severe GBA1 mutations. When examining macroautophagy, we observed reduced formation of autophagosomes in cells with the N370S and D409H GBA1 mutations and impairments in autophagosome-lysosome fusion in cells with the L444P GBA1 mutation. Accordingly, severe GBA1 mutations were found to trigger the accumulation and release of oligomeric α-synuclein in iPSC-derived dopaminergic neurons, primarily as a result of increased ER stress and defective macroautophagy, while mild GBA1 mutations affected CMA, which is mainly responsible for the degradation of the monomeric form of α-synuclein. Overall, our findings provide new insight into the molecular basis of the clinical variability in PD associated with different GBA1 mutations.
Collapse
Affiliation(s)
- G Onal
- Department of Physiology, Anatomy and Genetics, Kavli Institute for NanoScience Discovery, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
| | - G Yalçın-Çakmaklı
- Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - C E Özçelik
- National Nanotechnology Research Center, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Turkey
| | - I Boussaad
- Translational Neuroscience, Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - U Ö Ş Şeker
- Interdisciplinary Neuroscience Program, National Nanotechnology Research Center, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Turkey
| | - Hugo J R Fernandes
- Department of Physiology, Anatomy and Genetics, Kavli Institute for NanoScience Discovery, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
| | - H Demir
- Department of Pediatric Gastroenterology, Hepatology and Nutrition, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - R Krüger
- Translational Neuroscience, Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
- Transversal Translational Medicine, Luxembourg Institute of Health (LIH), Strassen, Luxembourg
- Parkinson Research Clinic, Centre Hospitalier de Luxembourg (CHL), Luxembourg City, Luxembourg
| | - B Elibol
- Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - S Dökmeci
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - M M Salman
- Department of Physiology, Anatomy and Genetics, Kavli Institute for NanoScience Discovery, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
| |
Collapse
|