Project description:Duplication of the SNCA gene (SNCADupl), linked to elevated levels of alpha-synuclein (aSyn), is a genetic cause of Parkinson's disease (PD). Our prior work with human-induced pluripotent stem cell (hiPSC)-derived midbrain neurons generated from PD SNCADupl patients identified neuritic deficits, accompanied by decreased levels of cytoskeletal element b-tubulin-III (bTubIII). To explore mechanisms underlying these effects in SNCADupl neurons, we employed CRISPR/Cas9 to generate isogenic control hiPSCs. Isogenic correction of SNCA dosage restored SNCADupl-induced neurite defects and bTubIII levels. Multi-omics analyses revealed SNCADupl-induced alterations in neuronal differentiation, with a notable downregulation of PAX6. Moreover, SNCADupl induced an upregulation of vimentin. Further characterization revealed heightened vimentin truncation, associated with altered distribution and organization. Similar changes in vimentin levels and truncation were observed in post-mortem putamen tissue from sporadic PD patients. Notably, targeting vimentin with okadaic acid and withaferin A restored bTubIII- and neurite-associated defects, suggesting its potential to prevent aSyn-mediated neuritic degeneration.
Project description:Synucleinopathies, including Parkinson’s disease, are characterized by α-synuclein (SNCA) aggregation and progressive neurodegeneration, yet the early molecular events linking SNCA gene dosage to disrupted proteostasis remain poorly understood. Here, we used human midbrain organoids derived from induced pluripotent stem cells (iPSC) carrying an SNCA triplication (SNCA Trip) and the isogenic corrected line (SNCA Isog) to dissect early pathogenic mechanisms in a 3D human model of synucleinopathy. We combined immunohistochemistry, immunoblotting, tandem mass tag proteomics, bulk RNA sequencing, and ribosome profiling to systematically characterize molecular alterations in SNCA Trip organoids at day 50 (D50) and day 100 (D100) of maturation. SNCA Trip organoids exhibited increased α-synuclein accumulation, neuromelanin deposition, and activation of mTORC1 (p-rpS6), ERK1/2, AKT and p-eIF2α signalling pathways by D100. Proteomic and transcriptomic analyses revealed upregulation of cytoskeletal, synaptic, and axonal development pathways, alongside significant downregulation of extracellular matrix (ECM) components and upregulation of perineuronal net (PNN) genes. Ribosome profiling showed minimal global translational changes but uncovered selective translational buffering of neuronal and ECM-associated transcripts. Confocal imaging confirmed progressive disorganization of pericellular and interstitial ECM structures around neurons in SNCA Trip organoids. Our findings demonstrate that SNCA triplication induces early proteostatic disruption and extracellular matrix remodelling prior to neurodegeneration and suggest that altered gene expression and ECM homeostasis may contribute to disease initiation and progression. Targeting these early aberrant mechanisms may offer new therapeutic opportunities for synucleinopathies, such as Parkinson’s Disease.
Project description:Synucleinopathies, including Parkinson’s disease, are characterized by α-synuclein (SNCA) aggregation and progressive neurodegeneration, yet the early molecular events linking SNCA gene dosage to disrupted proteostasis remain poorly understood. Here, we used human midbrain organoids derived from induced pluripotent stem cells (iPSC) carrying an SNCA triplication (SNCA Trip) and the isogenic corrected line (SNCA Isog) to dissect early pathogenic mechanisms in a 3D human model of synucleinopathy. We combined immunohistochemistry, immunoblotting, tandem mass tag proteomics, bulk RNA sequencing, and ribosome profiling to systematically characterize molecular alterations in SNCA Trip organoids at day 50 (D50) and day 100 (D100) of maturation. SNCA Trip organoids exhibited increased α-synuclein accumulation, neuromelanin deposition, and activation of mTORC1 (p-rpS6), ERK1/2, AKT and p-eIF2α signalling pathways by D100. Proteomic and transcriptomic analyses revealed upregulation of cytoskeletal, synaptic, and axonal development pathways, alongside significant downregulation of extracellular matrix (ECM) components and upregulation of perineuronal net (PNN) genes. Ribosome profiling showed minimal global translational changes but uncovered selective translational buffering of neuronal and ECM-associated transcripts. Confocal imaging confirmed progressive disorganization of pericellular and interstitial ECM structures around neurons in SNCA Trip organoids. Our findings demonstrate that SNCA triplication induces early proteostatic disruption and extracellular matrix remodelling prior to neurodegeneration and suggest that altered gene expression and ECM homeostasis may contribute to disease initiation and progression. Targeting these early aberrant mechanisms may offer new therapeutic opportunities for synucleinopathies, such as Parkinson’s Disease.
Project description:Duplication of the SNCA gene (SNCADupl), linked to elevated levels of alpha-synuclein (aSyn), is a genetic cause of Parkinson's disease (PD). Our prior work with human-induced pluripotent stem cell (hiPSC)-derived midbrain neurons generated from PD SNCADupl patients identified neuritic deficits, accompanied by decreased levels of cytoskeletal element b-tubulin-III (bTubIII). To explore the underlying mechanisms for these effects in SNCADupl neurons, we employed CRISPR/Cas9 technology to generate isogenic control hiPSCs. Isogenic correction of SNCA dosage restored SNCADupl-induced neurite morphologic defects and decreased bTubIII levels. Multi-omics analyses revealed SNCADupl-induced upregulation of the cytoskeletal protein vimentin. Further characterization revealed heightened vimentin truncation, associated with altered distribution and organization. Similar changes in vimentin levels and truncation were observed in post-mortem putamen tissue from sporadic PD patients. Notably, interference with vimentin by okadaic acid and withaferin A restored bTubIII- and neurite-associated defects, suggesting that targeting vimentin potentially prevents aSyn-mediated neuritic degeneration.
Project description:Duplication of the SNCA gene (SNCADupl), linked to elevated levels of alpha-synuclein (aSyn), is a genetic cause of Parkinson's disease (PD). Our prior work with human-induced pluripotent stem cell (hiPSC)-derived midbrain neurons generated from PD SNCADupl patients identified neuritic deficits, accompanied by decreased levels of cytoskeletal element b-tubulin-III (bTubIII). To explore the underlying mechanisms for these effects in SNCADupl neurons, we employed CRISPR/Cas9 technology to generate isogenic control hiPSCs. Isogenic correction of SNCA dosage restored SNCADupl-induced neurite morphologic defects and decreased bTubIII levels. Multi-omics analyses revealed SNCADupl-induced upregulation of the cytoskeletal protein vimentin. Further characterization revealed heightened vimentin truncation, associated with altered distribution and organization. Similar changes in vimentin levels and truncation were observed in post-mortem putamen tissue from sporadic PD patients. Notably, interference with vimentin by okadaic acid and withaferin A restored bTubIII- and neurite-associated defects, suggesting that targeting vimentin potentially prevents aSyn-mediated neuritic degeneration.
Project description:au06-03_tsn_fj - tsn_fj - Root transcriptome of the tsn1 tsn2 double mutant - Comparison of a tsn1 tsn2 double mutant line (A10.9.3- or A13.3.11-) and an isogenic line complemented by TSN2 (A10.9.5) or TSN1 (A13.3.2) Keywords: gene knock in (transgenic),gene knock out
Project description:A major barrier to research on Parkinson’s disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding ?-synuclein. ?-Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double ?-synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of ?-synuclein, and for mechanistic experiments to study PD pathogenesis. This SNP microarray study was carried out to confirm presence of SNCA triplication in the affected subject and the derived cell lines. 11 samples were analysed: genomic DNA from the two subjects in the study, the two parent fibroblast lines (AST denoting alpha-synuclein triplication and NAS denoting normal alpha-synuclein), two iPSC lines from each parent fibroblast line (four in total), a human embryonic stem cell line (SHEF4) and two neuronal samples one each from AST and NAS iPSCs).
Project description:A major barrier to research on Parkinson’s disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding α-synuclein. α-Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double α-synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of α-synuclein, and for mechanistic experiments to study PD pathogenesis. This gene expression microarray study was carried out as part of the validation process for demonstrating that the generated iPSC lines are pluripotent. 15 samples were analysed: the two parent fibroblast lines (AST denoting alpha-synuclein triplication and NAS denoting normal alpha-synuclein), two iPSC lines from each parent fibroblast line (four in total), a human embryonic stem cell line (SHEF4) and eight neuronal samples (each iPSC line differentiated into a neuronal population enriched for dopaminergic neurons, at two different time points).