Commentary: Parkinson disease-linked GBA mutation effects reversed by molecular chaperones in human cell and fly models

A commentary on Parkinson disease-linked GBA mutation effects reversed by molecular chaperones in human cell and fly models by Sanchez-Martinez,A.,Beavan,M.,Gegg,M.E.,Chau,K.-Y.,Whitworth,A.J.,andSchapira,A. H. V.(2016).Sci.Rep.6:31380.doi:10.1038/srep3138

Commentary: Parkinson disease-linked GBA mutation effects reversed by molecular chaperones in human cell and fly models

A commentary on Parkinson disease-linked GBA mutation effects reversed by molecular chaperones in human cell and fly models by Sanchez-Martinez,A.,Beavan,M.,Gegg,M.E.,Chau,K.-Y.,Whitworth,A.J.,andSchapira,A. H. V.(2016).Sci.Rep.6:31380.doi:10.1038/srep3138

Cellular α-synuclein pathology is associated with bioenergetic dysfunction in Parkinson's iPSC-derived dopamine neurons

Parkinson's disease (PD) is the second most common neurodegenerative disorder and a central role for α-Synuclein (αSyn; SNCA) in disease aetiology has been proposed based on genetics and neuropathology. To better understand the pathological mechanisms of αSyn, we generated induced pluripotent stem cells (iPSCs) from healthy individuals and PD patients carrying the A53T SNCA mutation or a triplication of the SNCA locus and differentiated them into dopaminergic neurons (DAn). iPSC-derived DAn from PD patients carrying either mutation showed increased intracellular αSyn accumulation, and DAn from patients carrying the SNCA triplication displayed oligomeric αSyn pathology and elevated αSyn extracellular release. Transcriptomic analysis of purified DAn revealed perturbations in expression of genes linked to mitochondrial function, consistent with observed reduction in mitochondrial respiration, impairment in mitochondrial membrane potential, aberrant mitochondrial morphology and decreased levels of phosphorylated DRP1Ser616. Parkinson's iPSC-derived DAn showed increased endoplasmic reticulum stress and impairments in cholesterol and lipid homeostasis. Together, these data show a correlation between αSyn cellular pathology and deficits in metabolic and cellular bioenergetics in the pathology of PD

ER stress and autophagic perturbations lead to elevated extracellular α-Synuclein in GBA-N370S Parkinson's iPSC-derived dopamine neurons

Heterozygous mutations in the glucocerebrosidase gene (GBA) represent the strongest common genetic risk factor for Parkinson's disease (PD), the second most common neurodegenerative disorder. However, the molecular mechanisms underlying this association are still poorly understood. Here, we have analyzed ten independent induced pluripotent stem cell (iPSC) lines from three controls and three unrelated PD patients heterozygous for the GBA-N370S mutation, and identified relevant disease mechanisms. After differentiation into dopaminergic neurons, we observed misprocessing of mutant glucocerebrosidase protein in the ER, associated with activation of ER stress and abnormal cellular lipid profiles. Furthermore, we observed autophagic perturbations and an enlargement of the lysosomal compartment specifically in dopamine neurons. Finally, we found increased extracellular α-synuclein in patient-derived neuronal culture medium, which was not associated with exosomes. Overall, ER stress, autophagic/lysosomal perturbations, and elevated extracellular α-synuclein likely represent critical early cellular phenotypes of PD, which might offer multiple therapeutic targets. In this article, Wade-Martins and colleagues show that in dopamine neurons from Parkinson's disease patients, the GBA-N370S mutation leads to the misprocessing of GCase, increased ER stress, and abnormal lipid profiles. Further, the GBA-N370S mutation impairs autophagic and lysosomal function, ultimately leading to increased α-synuclein release in dopaminergic neuronal cultures, which may be central in the early pathogenesis of Parkinson's disease

iPS cells in the study of PD molecular pathogenesis

Parkinson's disease (PD) is the second most common neurodegenerative disease and its pathogenic mechanisms are poorly understood. The majority of PD cases are sporadic but a number of genes are associated with familial PD. Sporadic and familial PD have many molecular and cellular features in common, suggesting some shared pathogenic mechanisms. Induced pluripotent stem cells (iPSCs) have been derived from patients harboring a range of different mutations of PD-associated genes. PD patient-derived iPSCs have been differentiated into relevant cell types, in particular dopaminergic neurons and used as a model to study PD. In this review, we describe how iPSCs have been used to improve our understanding of the pathogenesis of PD. We describe what cellular and molecular phenotypes have been observed in neurons derived from iPSCs harboring known PD-associated mutations and what common pathways may be involved