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Pitcairn C, Murata N, Zalon AJ, Stojkovska I, Mazzulli JR. Impaired Autophagic-Lysosomal Fusion in Parkinson's Patient Midbrain Neurons Occurs through Loss of ykt6 and Is Rescued by Farnesyltransferase Inhibition. J Neurosci 2023; 43:2615-2629. [PMID: 36788031 PMCID: PMC10082462 DOI: 10.1523/jneurosci.0610-22.2023] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 01/19/2023] [Accepted: 01/26/2023] [Indexed: 02/16/2023] Open
Abstract
Macroautophagy is a catabolic process that coordinates with lysosomes to degrade aggregation-prone proteins and damaged organelles. Loss of macroautophagy preferentially affects neuron viability and is associated with age-related neurodegeneration. We previously found that α-synuclein (α-syn) inhibits lysosomal function by blocking ykt6, a farnesyl-regulated soluble NSF attachment protein receptor (SNARE) protein that is essential for hydrolase trafficking in midbrain neurons. Using Parkinson's disease (PD) patient iPSC-derived midbrain cultures, we find that chronic, endogenous accumulation of α-syn directly inhibits autophagosome-lysosome fusion by impairing ykt6-SNAP-29 complexes. In wild-type (WT) cultures, ykt6 depletion caused a near-complete block of autophagic flux, highlighting its critical role for autophagy in human iPSC-derived neurons. In PD, macroautophagy impairment was associated with increased farnesyltransferase (FTase) activity, and FTase inhibitors restored macroautophagic flux through promoting active forms of ykt6 in human cultures, and male and female mice. Our findings indicate that ykt6 mediates cellular clearance by coordinating autophagic-lysosomal fusion and hydrolase trafficking, and that macroautophagy impairment in PD can be rescued by FTase inhibitors.SIGNIFICANCE STATEMENT The pathogenic mechanisms that lead to the death of neurons in Parkinson's disease (PD) and Dementia with Lewy bodies (LBD) are currently unknown. Furthermore, disease modifying treatments for these diseases do not exist. Our study indicates that a cellular clearance pathway termed autophagy is impaired in patient-derived culture models of PD and in vivo We identified a novel druggable target, a soluble NSF attachment protein receptor (SNARE) protein called ykt6, that rescues autophagy in vitro and in vivo upon blocking its farnesylation. Our work suggests that farnesyltransferase (FTase) inhibitors may be useful therapies for PD and DLB through enhancing autophagic-lysosomal clearance of aggregated proteins.
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Affiliation(s)
- Caleb Pitcairn
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Naomi Murata
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Annie J Zalon
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Iva Stojkovska
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Joseph R Mazzulli
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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Tomagra G, Picollo F, Battiato A, Picconi B, De Marchis S, Pasquarelli A, Olivero P, Marcantoni A, Calabresi P, Carbone E, Carabelli V. Quantal Release of Dopamine and Action Potential Firing Detected in Midbrain Neurons by Multifunctional Diamond-Based Microarrays. Front Neurosci 2019; 13:288. [PMID: 31024230 PMCID: PMC6465646 DOI: 10.3389/fnins.2019.00288] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [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: 01/10/2019] [Accepted: 03/11/2019] [Indexed: 12/20/2022] Open
Abstract
Micro-Graphitic Single Crystal Diamond Multi Electrode Arrays (μG-SCD-MEAs) have so far been used as amperometric sensors to detect catecholamines from chromaffin cells and adrenal gland slices. Besides having time resolution and sensitivity that are comparable with carbon fiber electrodes, that represent the gold standard for amperometry, μG-SCD-MEAs also have the advantages of simultaneous multisite detection, high biocompatibility and implementation of amperometric/potentiometric protocols, aimed at monitoring exocytotic events and neuronal excitability. In order to adapt diamond technology to record neuronal activity, the μG-SCD-MEAs in this work have been interfaced with cultured midbrain neurons to detect electrical activity as well as quantal release of dopamine (DA). μG-SCD-MEAs are based on graphitic sensing electrodes that are embedded into the diamond matrix and are fabricated using MeV ion beam lithography. Two geometries have been adopted, with 4 × 4 and 8 × 8 microelectrodes (20 μm × 3.5 μm exposed area, 200 μm spacing). In the amperometric configuration, the 4 × 4 μG-SCD-MEAs resolved quantal exocytosis from midbrain dopaminergic neurons. KCl-stimulated DA release occurred as amperometric spikes of 15 pA amplitude and 0.5 ms half-width, at a mean frequency of 0.4 Hz. When used as potentiometric multiarrays, the 8 × 8 μG-SCD-MEAs detected the spontaneous firing activity of midbrain neurons. Extracellularly recorded action potentials (APs) had mean amplitude of ∼-50 μV and occurred at a mean firing frequency of 0.7 Hz in 67% of neurons, while the remaining fired at 6.8 Hz. Comparable findings were observed using conventional MEAs (0.9 and 6.4 Hz, respectively). To test the reliability of potentiometric recordings with μG-SCD-MEAs, the D2-autoreceptor modulation of firing was investigated by applying levodopa (L-DOPA, 20 μM), and comparing μG-SCD-MEAs, conventional MEAs and current-clamp recordings. In all cases, L-DOPA reduced the spontaneous spiking activity in most neurons by 70%, while the D2-antagonist sulpiride reversed this effect. Cell firing inhibition was generally associated with increased APs amplitude. A minority of neurons was either insensitive to, or potentiated by L-DOPA, suggesting that AP recordings originate from different midbrain neuronal subpopulations and reveal different modulatory pathways. Our data demonstrate, for the first time, that μG-SCD-MEAs are multi-functional biosensors suitable to resolve real-time DA release and AP firing in in vitro neuronal networks.
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Affiliation(s)
- Giulia Tomagra
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Federico Picollo
- Department of Physics and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy.,Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Alfio Battiato
- Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Barbara Picconi
- Experimental Neurophysiology Laboratory, IRCCS San Raffaele Pisana, University San Raffaele, Rome, Italy.,University San Raffaele, Rome, Italy
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology and "NICO" Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Turin, Italy
| | | | - Paolo Olivero
- Department of Physics and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy.,Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Andrea Marcantoni
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Paolo Calabresi
- Neurological Clinic, Department of Medicine, Hospital Santa Maria della Misericordia, University of Perugia, Perugia, Italy
| | - Emilio Carbone
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Valentina Carabelli
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
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