Cell cycle arrest of neural progenitors causes impaired dopaminergic neuronal differentiation in GBA associated Parkinson’s disease midbrain organoids [2]
Ontology highlight
ABSTRACT: The mechanisms underlying Parkinson's disease (PD) etiology are only partially understood despite intensive research conducted in the field. Recent evidence suggests that early neurodevelopmental defects might play a role in cellular susceptibility to neurodegeneration. To study the early developmental contribution of GBA mutations in PD we used patient-derived iPSCs carrying a heterozygous N370S mutation in the GBA gene. Patient-specific midbrain organoids displayed GBA-PD relevant phenotypes such as reduction of GCase activity, autophagy impairment and mitochondrial dysfunction. Genome-scale metabolic (GEM) modeling predicted changes in lipid metabolism which were validated with lipidomics analysis, showing significant differences in the lipidome of GBA-PD. In addition, patient-specific midbrain organoids exhibited an increase in the neural progenitor population showing signs of cellular senescence. This was accompanied by a decrease in the number and complexity of dopaminergic neurons. These results provide insights into how GBA mutations may lead to neurodevelopmental defects thereby predisposing to PD pathology.
Project description:The mechanisms underlying Parkinson's disease (PD) etiology are only partially understood despite intensive research conducted in the field. Recent evidence suggests that early neurodevelopmental defects might play a role in cellular susceptibility to neurodegeneration. To study the early developmental contribution of GBA mutations in PD we used patient-derived iPSCs carrying a heterozygous N370S mutation in the GBA gene. Patient-specific midbrain organoids displayed GBA-PD relevant phenotypes such as reduction of GCase activity, autophagy impairment and mitochondrial dysfunction. Genome-scale metabolic (GEM) modeling predicted changes in lipid metabolism which were validated with lipidomics analysis, showing significant differences in the lipidome of GBA-PD. In addition, patient-specific midbrain organoids exhibited an increase in the neural progenitor population showing signs of cellular senescence. This was accompanied by a decrease in the number and complexity of dopaminergic neurons. These results provide insights into how GBA mutations may lead to neurodevelopmental defects thereby predisposing to PD pathology.
Project description:We compared transcriptome of monocyte-derived macrophages of 5 patients with GBA-PD (4 L444P/N, 1 N370S/N) and 4 asymptomatic GBA mutation carriers (GBA-carriers) (3 L444P/N, 1 N370S/N) and 4 controls. We also conducted comparative transcriptome analysis for L444P/N only GBA-PD patients and GBA-carriers. Revealed deregulated genes in GBA-PD independently of GBA mutations (L444P or N370S) were involved in immune response, neuronal function. We found upregulated pathway associated with zinc metabolism in L444P/N GBA-PD patients. The potential important role of DUSP1 in the pathogenesis of GBA-PD was suggested.
Project description:We compared transcriptome of monocyte-derived macrophages of 5 patients with GBA-PD (4 L444P/N, 1 N370S/N) and 4 asymptomatic GBA mutation carriers (GBA-carriers) (3 L444P/N, 1 N370S/N) and 4 controls. We also conducted comparative transcriptome analysis for L444P/N only GBA-PD patients and GBA-carriers. Revealed deregulated genes in GBA-PD independently of GBA mutations (L444P or N370S) were involved in immune response, neuronal function. We found upregulated pathway associated with zinc metabolism in L444P/N GBA-PD patients. The potential important role of DUSP1 in the pathogenesis of GBA-PD was suggested.
Project description:Heterozygous mutations in the glucocerebrosidase gene (GBA) are the strongest common genetic risk factors for Parkinson’s disease (PD) present in around 5-10% of PD patients, resulting in lower age of onset and exacerbating disease progression, including an increased risk of dementia. However, the exact mechanisms leading from dysfunction of the enzyme glucocerebrosidase (GCase) encoded by GBA to PD pathogenesis and neurodegeneration remain unclear. Applying a novel multi-part enrichment workflow we have developed, we have isolated and quantified peptides with phosphorylation, cysteine-modification or N-linked glycosylation simultaneously. We applied this methodology to iPSC-derived dopaminergic neurons from GBA-N370S PD patients and healthy age-matched controls, identifying large numbers of dysregulated native and modified proteins.
Project description:Growing evidence indicates that Type 2 diabetes (T2D) is associated with an increased risk of developing PD Parkinson’s disease (PD) through shared disease mechanisms. Studies show that insulin resistance, which is the driving pathophysiological mechanism of T2D plays a major role in neurodegeneration by impairing neuronal functionality, metabolism, and survival. To better understand the importance of insulin signalling in the human midbrain, which is the most affected brain region in PD, we expose IPSC-derived human midbrain organoids from healthy individuals and GBA-N370S mutation-carrying PD patients to either high insulin concentrations, promoting insulin resistance, or to more physiological insulin concentrations restoring normal insulin signalling function. We are able to show that insulin resistance compromises dopaminergic neuron and dopamine levels in the midbrain organoids of healthy donors. Moreover, insulin-resistant organoids display diminished neuronal activity and reduced metabolic efficiency. Furthermore, our findings demonstrate FOXO1 role in GBA-PD phenotype severity and show the potential beneficial effects of the anti-diabetic drug Pioglitazone in GBA-PD treatment. Overall, our results highlight insulin resistance as a significant target in PD prevention and disease-modifying therapy.
Project description:Growing evidence indicates that Type 2 diabetes (T2D) is associated with an increased risk of developing PD Parkinson’s disease (PD) through shared disease mechanisms. Studies show that insulin resistance, which is the driving pathophysiological mechanism of T2D plays a major role in neurodegeneration by impairing neuronal functionality, metabolism, and survival. To better understand the importance of insulin signalling in the human midbrain, which is the most affected brain region in PD, we expose IPSC-derived human midbrain organoids from healthy individuals and GBA-N370S mutation-carrying PD patients to either high insulin concentrations, promoting insulin resistance, or to more physiological insulin concentrations restoring normal insulin signalling function. We are able to show that insulin resistance compromises dopaminergic neuron and dopamine levels in the midbrain organoids of healthy donors. Moreover, insulin-resistant organoids display diminished neuronal activity and reduced metabolic efficiency. Furthermore, our findings demonstrate FOXO1 role in GBA-PD phenotype severity and show the potential beneficial effects of the anti-diabetic drug Pioglitazone in GBA-PD treatment. Overall, our results highlight insulin resistance as a significant target in PD prevention and disease-modifying therapy.
Project description:Parkinson’s disease (PD) is a progressive neurodegenerative disorder with no effective treatment. Advances in neuroscience and systems biomedicine now enable the use of complex patient-specific in vitro disease models and cutting-edge computational tools for data integration, enhancing our understanding of complex PD mechanisms. To explore common biomedical features across monogenic PD forms, we developed a knowledge graph (KG) by integrating previously published high-content imaging and RNA sequencing data of PD patient-specific midbrain organoids harbouring LRRK2-G2019S, SNCA triplication, GBA-N370S or MIRO1-R272Q mutation with publicly available biological data. Furthermore, we generated a single-cell RNA sequencing dataset of midbrain organoids derived from idiopathic PD patients (IPD) to stratify IPD patients towards genetic forms of PD.
Project description:Parkinson’s disease (PD) is a prevalent neurodegenerative disorder that is characterized by the selective loss of midbrain dopamine (DA)-producing neurons and the formation of α-synuclein (α-syn)-containing inclusions named Lewy bodies (LBs). Here, we report that the loss of glucocerebrosidase (GCase), coupled with α-syn overexpression, result in substantial accumulation of detergent-resistant α-syn aggregates and Lewy body-like inclusions (LBLIs) in human midbrain-like organoids (hMLOs). These LBLIs exhibit a highly similar structure to PD-associated LBs, by displaying a spherically symmetric morphology with an eosinophilic core, and containing α-syn and ubiquitin. Importantly, hMLOs generated from PD patient-derived inducible pluripotent stem cells (iPSCs) harboring SNCA triplication also exhibit subsequent degeneration of DA neurons and LBLI formation upon chronic GCase inhibitor treatment. Taken together, our hMLOs harbouring two major PD risk factors (GCase deficiency and overproduced α-syn) successfully recapitulate major pathophysiological signatures of the disease, and highlight the broad utility of brain organoid technology in modeling human neurodegenerative diseases.
Project description:Mutations in the lysosomal enzyme β-glucocerebrosidase (GCase), which cause Gaucher´s disease, are the most frequent genetic risk factor for Parkinson’s disease (PD). Here, we employed single-cell genomic approaches in induced pluripotent stem cell (iPSC)-derived midbrain organoids to dissect the mechanisms underlying GCase-related neurodegeneration.
Project description:The most common genetic risk factors for Parkinson’s disease (PD) are a set of heterozygous mutant (MT) alleles of the GBA1 gene that encodes Beta-glucocerebrosidase (GCase), an enzyme normally trafficked through the ER/ Golgi apparatus to the lysosomal lumen. We found that half of the GCase in lysosomes from post-mortem human GBA-PD brains was present on the lysosomal surface, and that this mislocalization depends on a pentapeptide motif in GCase used to target cytosolic protein for degradation by chaperone-mediated autophagy (CMA). Unfolded mutant GCase at the lysosomal surface inhibits CMA, causing accumulation of CMA substrates including -synuclein. Using single cell transcriptional analysis and comparative proteomics of brains from GBA-PD patients we confirmed reduced CMA activity and proteome changes comparable to those in CMA-deficient mouse brain. Loss of the MT GCase CMA motif is sufficient to rescue primary substantia nigra dopamine neurons from MT-GCase induced neuronal death. We conclude that MT GCase alleles block CMA function and produce -synuclein accumulation.