Project description:Aggregated α-synuclein (α-SYN) proteins, encoded by the SNCA gene, are hallmarks of Lewy body disease (LBD), affecting multiple brain regions. However, the specific mechanisms underlying α-SYN pathology in cortical neurons, crucial for LBD-associated dementia, remain unclear. Here, we generated human cortical LBD models by differentiating induced pluripotent stem cells (iPSCs) from SNCA triplication LBD patients into cerebral organoids and observed increased levels of pathological α-SYN in these organoids. Single-cell RNA sequencing revealed prominent expression of the SNCA gene in excitatory neurons, which exhibited synaptic and mitochondrial dysfunction, consistent with findings in the cortex of LBD human brains. Furthermore, screening 1280 FDA-approved drugs identified four candidates, which inhibited α-SYN seeding in RT-QuIC assay, reduced α-SYN aggregation and alleviated mitochondrial dysfunction in SNCA triplication iPSC models. Our findings provide valuable insights into the development of cortical LBD models and the discovery of potential drugs targeting α-SYN aggregation.
Project description:Aggregated α-synuclein (α-SYN) proteins, encoded by the SNCA gene, are hallmarks of Lewy body disease (LBD), affecting multiple brain regions. However, the specific mechanisms underlying α-SYN pathology in cortical neurons, crucial for LBD-associated dementia, remain unclear. Here, we generated human cortical LBD models by differentiating induced pluripotent stem cells (iPSCs) from SNCA triplication LBD patients into cerebral organoids and observed increased levels of pathological α-SYN in these organoids. Single-cell RNA sequencing revealed prominent expression of the SNCA gene in excitatory neurons, which exhibited synaptic and mitochondrial dysfunction, consistent with findings in the cortex of LBD human brains. Furthermore, screening 1280 FDA-approved drugs identified four candidates, which inhibited α-SYN seeding in RT-QuIC assay, reduced α-SYN aggregation and alleviated mitochondrial dysfunction in SNCA triplication iPSC models. Our findings provide valuable insights into the development of cortical LBD models and the discovery of potential drugs targeting α-SYN aggregation.
Project description:Parkinson’s disease is characterized by the aggregation of the presynaptic protein α-synuclein and its deposition into pathologic Lewy bodies. While extensive research has been carried out on mediators of α-synuclein aggregation, molecular facilitators of α-synuclein disaggregation are still generally unknown. We investigated the role of molecular chaperones in both preventing and disaggregating α-synuclein oligomers and fibrils, with a focus on the mammalian disaggregase complex. Here, we show that overexpression of the chaperone Hsp110 is sufficient to reduce α-synuclein aggregation in a mammalian cell culture model. Additionally, we demonstrate that Hsp110 effectively mitigates α-synuclein pathology in vivo through the characterization of transgenic Hsp110 and double transgenic α-synuclein/Hsp110 mouse models. Unbiased analysis of the synaptic proteome of these mice revealed that overexpression of Hsp110 can override the protein changes driven by the α-synuclein transgene. Furthermore, overexpression of Hsp110 is sufficient to prevent endogenous α-synuclein templating and spread following injection of aggregated α-synuclein seeds into brain, supporting a role for Hsp110 in the prevention and/or disaggregation of α-synuclein pathology.
Project description:Recombinant inbred lines were created by crossing the alpha-synuclein containing Caenorhabditis elegans strains NL5901 and SCH4856. These strains contain the human alpha-synuclein gene fused to YFP and under the control of an unc-54 promotor (unc-54p::alpha-synnuclein::YFP) in an N2 and CB4856 genetic background, respectively. These two strains were used to generate a total of 212 recombinant inbred lines, of which 88 were genotyped by whole-genome sequencing using a MiSeq. These recombinant inbred lines can be used for mapping genetic modifiers affecting protein accumulation.
Project description:The gastrointestinal tract may be a site of origin for α-synuclein (α-syn) pathology in idiopathic Parkinson’s disease (PD), and an abundance of aggregated α-syn has recently been demonstrated in both the healthy and PD appendix. However, the molecular changes that enable gut α-syn aggregates to contribute to the development and progression of PD remain unclear. Here, our deep-sequencing of DNA methylation changes at 521 autophagy-lysosomal pathway (ALP) genes in the human appendix and brain in PD and healthy controls indicates a pattern of widespread hypermethylation in the PD appendix that is recapitulated in the PD brain. There is significant overlap in the individual ALP genes affected across the PD appendix and brain, with lysosomal genes specifically downregulated in both regions. Healthy epigenetic aging, which involves a hypermethylation of macroautophagy and selective autophagy genes in the appendix and brain, is disrupted in both areas in PD. In mice, DNA methylation changes at ALP genes induced by chronic gut inflammation are greatly exacerbated by the presence of α-syn pathology. DNA methylation changes at ALP genes induced by α-synucleinopathy are significantly associated with the ALP abnormalities observed in the PD appendix, specifically involving lysosomal genes. Our work, which constitutes an in-depth, unbiased investigation of epigenetic changes in the ALP of the PD gut and brain, identifies the epigenetic misregulation of the ALP, especially a downregulation of lysosomal genes, as a potential culprit for the initiation and spread of α-syn pathology in idiopathic PD.
Project description:In synucleinopathies, including Parkinson’s disease, α-synuclein (α-Syn) misfolds and forms Ser129-phosphorylated aggregates (pSyn). Mitochondrial and lysosomal dysfunction, along with impairments in protein and organelle trafficking, exacerbate α-Syn pathology through poorly defined molecular mechanisms. We used CRISPR-mediated gene activation and ablation to systematically interrogate mitochondrial, trafficking and motility-related genes to identify pSyn regulators in HEK293 cells exposed to α-Syn fibrils. We found that activation of the mitochondrial protein OXR1 increased pSyn by impairing ATP synthesis and altering the mitochondrial membrane potential, whereas ablation of the endoplasmic reticulum (ER)-associated protein EMC4 reduced pSyn by enhancing ER-driven autophagic flux and lysosomal clearance. Assays with distinct strains of α-Syn fibrils revealed that OXR1 was preferentially synergistic with multiple system atrophy (MSA)-associated fibrils, whereas EMC4 broadly reduced pSyn across diverse α-Syn polymorphs. These findings were validated in human iPSC-derived cortical and dopaminergic neurons, with OXR1 preferentially driving somatic aggregation and EMC4 depleting both somatic and neuritic aggregates. This work identifies OXR1 and EMC4 as organelle-specific regulators of α-Syn proteostasis and underscores the involvement of mitochondrial and ER-lysosomal pathways in synucleinopathies.
Project description:The gastrointestinal tract may be a site of origin for α-synuclein (α-syn) pathology in idiopathic Parkinson’s disease (PD), and an abundance of aggregated α-syn has recently been demonstrated in both the healthy and PD appendix. However, the molecular changes that enable gut α-syn aggregates to contribute to the development and progression of PD remain unclear. Here, our deep-sequencing of DNA methylation changes at 521 autophagy-lysosomal pathway (ALP) genes in the human appendix and brain in PD and healthy controls indicates a pattern of widespread hypermethylation in the PD appendix that is recapitulated in the PD brain. There is significant overlap in the individual ALP genes affected across the PD appendix and brain, with lysosomal genes specifically downregulated in both regions. Healthy epigenetic aging, which involves a hypermethylation of macroautophagy and selective autophagy genes in the appendix and brain, is disrupted in both areas in PD. In mice, DNA methylation changes at ALP genes induced by chronic gut inflammation are greatly exacerbated by the presence of α-syn pathology. DNA methylation changes at ALP genes induced by α-synucleinopathy are significantly associated with the ALP abnormalities observed in the PD appendix, specifically involving lysosomal genes. Our work, which constitutes an in-depth, unbiased investigation of epigenetic changes in the ALP of the PD gut and brain, identifies the epigenetic misregulation of the ALP, especially a downregulation of lysosomal genes, as a potential culprit for the initiation and spread of α-syn pathology in idiopathic PD.
Project description:The gastrointestinal tract may be a site of origin for α-synuclein (α-syn) pathology in idiopathic Parkinson’s disease (PD), and an abundance of aggregated α-syn has recently been demonstrated in both the healthy and PD appendix. However, the molecular changes that enable gut α-syn aggregates to contribute to the development and progression of PD remain unclear. Here, our deep-sequencing of DNA methylation changes at 521 autophagy-lysosomal pathway (ALP) genes in the human appendix and brain in PD and healthy controls indicates a pattern of widespread hypermethylation in the PD appendix that is recapitulated in the PD brain. There is significant overlap in the individual ALP genes affected across the PD appendix and brain, with lysosomal genes specifically downregulated in both regions. Healthy epigenetic aging, which involves a hypermethylation of macroautophagy and selective autophagy genes in the appendix and brain, is disrupted in both areas in PD. In mice, DNA methylation changes at ALP genes induced by chronic gut inflammation are greatly exacerbated by the presence of α-syn pathology. DNA methylation changes at ALP genes induced by α-synucleinopathy are significantly associated with the ALP abnormalities observed in the PD appendix, specifically involving lysosomal genes. Our work, which constitutes an in-depth, unbiased investigation of epigenetic changes in the ALP of the PD gut and brain, identifies the epigenetic misregulation of the ALP, especially a downregulation of lysosomal genes, as a potential culprit for the initiation and spread of α-syn pathology in idiopathic PD.