![]() ; ; Antony, Paul ![]() in NPJ systems biology and applications (2020), 6(1), 38 Mitochondrial dysfunction is linked to pathogenesis of Parkinson's disease (PD). However, individual mitochondria-based analyses do not show a uniform feature in PD patients. Since mitochondria interact ... [more ▼] Mitochondrial dysfunction is linked to pathogenesis of Parkinson's disease (PD). However, individual mitochondria-based analyses do not show a uniform feature in PD patients. Since mitochondria interact with each other, we hypothesize that PD-related features might exist in topological patterns of mitochondria interaction networks (MINs). Here we show that MINs formed nonclassical scale-free supernetworks in colonic ganglia both from healthy controls and PD patients; however, altered network topological patterns were observed in PD patients. These patterns were highly correlated with PD clinical scores and a machine-learning approach based on the MIN features alone accurately distinguished between patients and controls with an area-under-curve value of 0.989. The MINs of midbrain dopaminergic neurons (mDANs) derived from several genetic PD patients also displayed specific changes. CRISPR/CAS9-based genome correction of alpha-synuclein point mutations reversed the changes in MINs of mDANs. Our organelle-interaction network analysis opens another critical dimension for a deeper characterization of various complex diseases with mitochondrial dysregulation. [less ▲] Detailed reference viewed: 64 (1 UL)![]() Hanss, Zoé ![]() ![]() ![]() in Movement Disorders (2020) Background: VPS35 is part of the retromer complex and is responsible for the trafficking and recycling of proteins implicated in autophagy and lysosomal degradation, but also takes part in the degradation ... [more ▼] Background: VPS35 is part of the retromer complex and is responsible for the trafficking and recycling of proteins implicated in autophagy and lysosomal degradation, but also takes part in the degradation of mitochondrial proteins via mitochondria-derived vesicles. The p.D620N mutation of VPS35 causes an autosomal-dominant form of Parkinson’s disease (PD), clinically representing typical PD. Objective: Most of the studies on p.D620N VPS35 were performed on human tumor cell lines, rodent models overexpressing mutant VPS35, or in patient-derived fibroblasts. Here, based on identified target proteins, we investigated the implication of mutant VPS35 in autophagy, lysosomal degradation, and mitochondrial function in induced pluripotent stem cell-derived neurons from a patient harboring the p.D620N mutation. Methods: We reprogrammed fibroblasts from a PD patient carrying the p.D620N mutation in the VPS35 gene and from two healthy donors in induced pluripotent stem cells. These were subsequently differentiated into neuronal precursor cells to finally generate midbrain dopaminergic neurons. Results: We observed a decreased autophagic flux and lysosomal mass associated with an accumulation of α-synuclein in patient-derived neurons compared to controls. Moreover, patient-derived neurons presented a mitochondrial dysfunction with decreased membrane potential, impaired mitochondrial respiration, and increased production of reactive oxygen species associated with a defect in mitochondrial quality control via mitophagy. Conclusion: We describe for the first time the impact of the p.D620N VPS35 mutation on autophago-lysosome pathway and mitochondrial function in stem cell-derived neurons from an affected p.D620N carrier and define neuronal phenotypes for future pharmacological interventions [less ▲] Detailed reference viewed: 97 (10 UL)![]() Larsen, Simone ![]() ![]() ![]() in Stem Cell Research (2020) Fibroblasts were obtained from a 76 year-old man diagnosed with Parkinson's disease (PD). The disease is caused by a heterozygous p.D620N mutation in VPS35. Induced pluripotent stem cells (iPSCs) were ... [more ▼] Fibroblasts were obtained from a 76 year-old man diagnosed with Parkinson's disease (PD). The disease is caused by a heterozygous p.D620N mutation in VPS35. Induced pluripotent stem cells (iPSCs) were generated using the CytoTune™-iPS 2.0 Sendai Reprogramming Kit (Thermo Fisher Scientific). The presence of the c.1858G > A base exchange in exon 15 of VPS35 was confirmed by Sanger sequencing. The iPSCs are free of genomically integrated reprogramming genes, express pluripotency markers, display in vitro differentiation potential to the three germ layers and have karyotypic integrity. Our iPSC line will be useful for studying the impact of the p.D620N mutation in VPS35 in vitro. [less ▲] Detailed reference viewed: 91 (8 UL)![]() Krüger, Rejko ![]() in Journal of Molecular Neuroscience (2020) Mutations in THAP1 (THAP domain-containing apoptosis-associated protein 1) are responsible for DYT6 dystonia. Until now, more than eighty differentmutations in THAP1 gene have been found in patientswith ... [more ▼] Mutations in THAP1 (THAP domain-containing apoptosis-associated protein 1) are responsible for DYT6 dystonia. Until now, more than eighty differentmutations in THAP1 gene have been found in patientswith primary dystonia, and two third of them are missense mutations. The potential pathogeneses of these missense mutations in human are largely elusive. In the present study, we generated stable transfected human neuronal cell lines expressing wild-type or mutated THAP1 proteins found in DYT6 patients. Transcriptional profiling using microarrays revealed a set of 28 common genes dysregulated in two mutated THAP1 (S21T and F81L) overexpression cell lines suggesting a common mechanism of these mutations. ChIP-seq showed that THAP1 can bind to the promoter of one of these genes, superoxide dismutase 2 (SOD2). Overexpression of THAP1 in SK-N-AS cells resulted in increased SOD2 protein expression, whereas fibroblasts from THAP1 patients have less SOD2 expression, which indicates that SOD2 is a direct target gene of THAP1. In addition, we show that some THAP1 mutations (C54Y and F81L) decrease the protein stability which might also be responsible for altered transcription regulation due to dosage insufficiency. Taking together, the current study showed different potential pathogenic mechanisms of THAP1 mutations which lead to the same consequence of DYT6 dystonia. [less ▲] Detailed reference viewed: 135 (0 UL)![]() Barbuti, Peter ![]() ![]() ![]() in Cells (2020), 9(9), The generation of isogenic induced pluripotent stem cell (iPSC) lines using CRISPR-Cas9 technology is a technically challenging, time-consuming process with variable efficiency. Here we use fluorescence ... [more ▼] The generation of isogenic induced pluripotent stem cell (iPSC) lines using CRISPR-Cas9 technology is a technically challenging, time-consuming process with variable efficiency. Here we use fluorescence-activated cell sorting (FACS) to sort biallelic CRISPR-Cas9 edited single-cell iPSC clones into high-throughput 96-well microtiter plates. We used high-content screening (HCS) technology and generated an in-house developed algorithm to select the correctly edited isogenic clones for continued expansion and validation. In our model we have gene-corrected the iPSCs of a Parkinson's disease (PD) patient carrying the autosomal dominantly inherited heterozygous c.88G>C mutation in the SNCA gene, which leads to the pathogenic p.A30P form of the alpha-synuclein protein. Undertaking a PCR restriction-digest mediated clonal selection strategy prior to sequencing, we were able to post-sort validate each isogenic clone using a quadruple screening strategy prior to generating footprint-free isogenic iPSC lines, retaining a normal molecular karyotype, pluripotency and three germ-layer differentiation potential. Directed differentiation into midbrain dopaminergic neurons revealed that SNCA expression is reduced in the gene-corrected clones, which was validated by a reduction at the alpha-synuclein protein level. The generation of single-cell isogenic clones facilitates new insights in the role of alpha-synuclein in PD and furthermore is applicable across patient-derived disease models. [less ▲] Detailed reference viewed: 137 (5 UL) |
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