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

Federico Zambon,Marta Cherubini,Rory Bowden,Richard Wade-Martins,Viola Volpato,Siv Vingill,Nora Bengoa-Vergniory,Caleb Webber,Jane Vowles,Heather D E Booth,Walther Haenseler,Moustafa Attar,Sally A Cowley,Hugo J R Fernandes,Charmaine Lang,Brent J Ryan

doi:10.1093/hmg/ddz038

Abstract

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 (DAns). iPSC-derived DAn from PD patients carrying either mutation showed increased intracellular αSyn accumulation, and DAns from patients carrying the SNCA triplication displayed oligomeric αSyn pathology and elevated αSyn extracellular release. Transcriptomic analysis of purified DAns 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 DAns 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.

Highlights

Parkinson’s disease (PD) is the second most common neurodegenerative disorder with adulthood onset and is characterized by the preferential loss of dopaminergic neurons (DAns) in the substantia nigra pars compacta (SNpc) in the midbrain
Feeder-free induced pluripotent stem cells (iPSCs) cultures remained positive for the pluripotency marker Oct3/4 [15], and 11 days after neuronal induction most cells were positive for the ventral midbrain markers FOXA2 and LMX1A, confirming efficient midbrain patterning [16]
We used iPSC-derived DAns from PD patients carrying the A53T SNCA or the SNCA Tripl mutation to study the cellular mechanisms associated with αSyn in PD pathology

Summary

Introduction

Parkinson’s disease (PD) is the second most common neurodegenerative disorder with adulthood onset and is characterized by the preferential loss of dopaminergic neurons (DAns) in the substantia nigra pars compacta (SNpc) in the midbrain. Human induced pluripotent stem cells (iPSCs) preserving an individual’s genetic background can be generated from PD patients and combined with protocols for the differentiation of iPSCs into DAns to generate highly relevant cell models to study PD pathology in vitro [11]. We carried out a thorough phenotypic analysis of DAns differentiated from nine independent iPSC lines, generated from three healthy individuals and four PD patients carrying either the A53T αSyn mutation (A53T SNCA) or a triplication of the SNCA locus (SNCA Tripl). Induction of ER stress and perturbations in cellular lipid biology were detected in both A53T SNCA and SNCA Tripl DAns. induction of ER stress and perturbations in cellular lipid biology were detected in both A53T SNCA and SNCA Tripl DAns Together, these data identify perturbations in protein accumulation, cellular metabolism and bioenergetics in the pathological mechanisms of PD and confirm the importance of patient stem cell models to study these pathways

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Results

Conclusion