Parkinson\u2019s disease patient-specific neuronal networks carrying the LRRK2 G2019S mutation unveil early functional alterations that predate neurodegeneration

G Carola,D Malagarriga,A Consiglio,E Tolosa,P Dell’Era,A Raya,V Baruffi,L Blasco-Agell,S Beltramone,I Fernandez-Carasa,A R Muotri,M Pons-Espinal,J Soriano,J Garcia Ojalvo,C Calatayud,J J Toledo-Aral,Y Richaud-Patin,E Molina

doi:10.1038/s41531-021-00198-3

Abstract

A deeper understanding of early disease mechanisms occurring in Parkinson’s disease (PD) is needed to reveal restorative targets. Here we report that human induced pluripotent stem cell (iPSC)-derived dopaminergic neurons (DAn) obtained from healthy individuals or patients harboring LRRK2 PD-causing mutation can create highly complex networks with evident signs of functional maturation over time. Compared to control neuronal networks, LRRK2 PD patients’ networks displayed an elevated bursting behavior, in the absence of neurodegeneration. By combining functional calcium imaging, biophysical modeling, and DAn-lineage tracing, we found a decrease in DAn neurite density that triggered overall functional alterations in PD neuronal networks. Our data implicate early dysfunction as a prime focus that may contribute to the initiation of downstream degenerative pathways preceding DAn loss in PD, highlighting a potential window of opportunity for pre-symptomatic assessment of chronic degenerative diseases.

Highlights

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, with an estimated prevalence in industrialized countries of 0.3% in the general population, which increases to 1.0% in people older than 60 years and to 3.0% in people older than 80 years[1]
At D50, the majority of the cells were positive for the dendritic marker MAP2, and quantitative immunolabeling for tyrosine hydroxylase (TH) and FOXA2 revealed that 30–40% of them were committed to DA neuronal fate (Fig. 1c, d)
We found that DA neurons derived from induced pluripotent stem cell (iPSC) representing healthy individuals or PD patients harboring LRRK2 mutation developed appropriate physiological characteristics forming complex and mature networks during the differentiation process

Summary

Introduction

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, with an estimated prevalence in industrialized countries of 0.3% in the general population, which increases to 1.0% in people older than 60 years and to 3.0% in people older than 80 years[1]. PD is characterized by classical motor syndrome linked to a progressive loss of dopamine-containing neurons (DAn) in the substantia nigra pars compacta, and disabling non-motor symptoms related to extranigral lesions. It has been proposed that early intervention might slow down or even stop disease progression, by preserving neurons from the undergoing irreversible neurodegeneration[1,2]. Current diagnostic modalities in PD are based on the presence of motor symptoms, a stage at which up to 70% of DAn have been lost[3]. Even though pre-motor symptoms are known to precede clinical diagnosis of PD by as much as a decade, they are rather unspecific and unsuitable as stand-alone biomarkers of the disease[4]. The identification of early diagnostic or progression markers of PD represents an urgent medical need

Methods

Results

Conclusion