Midbrain organoids mimic early embryonic neurodevelopment and recapitulate LRRK2-p.Gly2019Ser-associated gene expression

Alise Zagare,Kyriaki Barmpa,Semra Smajic,Lisa M Smits,Kamil Grzyb,Anne Grünewald,Alexander Skupin,Sarah L Nickels,Jens C Schwamborn

doi:10.1016/j.ajhg.2021.12.009

Alise Zagare, Kyriaki Barmpa + Show 7 more

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https://doi.org/10.1016/j.ajhg.2021.12.009

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Abstract

SummaryHuman brain organoid models that recapitulate the physiology and complexity of the human brain have a great potential for in vitro disease modeling, in particular for neurodegenerative diseases, such as Parkinson disease. In the present study, we compare single-cell RNA-sequencing data of human midbrain organoids to the developing human embryonic midbrain. We demonstrate that the in vitro model is comparable to its in vivo equivalents in terms of developmental path and cellular composition. Moreover, we investigate the potential of midbrain organoids for modeling early developmental changes in Parkinson disease. Therefore, we compare the single-cell RNA-sequencing data of healthy-individual-derived midbrain organoids to their isogenic LRRK2-p.Gly2019Ser-mutant counterparts. We show that the LRRK2 p.Gly2019Ser variant alters neurodevelopment, resulting in an untimely and incomplete differentiation with reduced cellular variability. Finally, we present four candidate genes, APP, DNAJC6, GATA3, and PTN, that might contribute to the LRRK2-p.Gly2019Ser-associated transcriptome changes that occur during early neurodevelopment.

Highlights

Parkinson disease (PD) is a multifactorial neurodegenerative disorder with varying motor and non-motor symptoms, characterized by the loss of dopaminergic neurons (DNs) in the substantia nigra pars compacta (SNpc) of the midbrain.[1]
Gene-editing of the induced pluripotent stem cells (iPSCs) was done with CRISP-Cas[9] and piggyBac systems, and it has been described in Qing et al, 2017.27 The derivation of Neural progenitor cells (NPCs) from iPSCs and further organoid generation have been described in detail previously[9,26] (Table S1)
Midbrain organoids show a gene expression signature comparable to the human embryonic midbrain To assess the similarity between the in vitro and in vivo midbrain systems, we compared scRNA-seq data of midbrain organoids cultured for 35 days (WT35) and 70 days (WT70)[26] to the human embryonic midbrain of developmental weeks 6–11.25 In addition, to investigate possible transcriptome similarities between midbrain organoids and other brain regions during early development, we compared the scRNA-seq data of midbrain organoids to scRNA-seq data of the human embryonic prefrontal cortex.[28]

Summary

Introduction

Parkinson disease (PD) is a multifactorial neurodegenerative disorder with varying motor and non-motor symptoms, characterized by the loss of dopaminergic neurons (DNs) in the substantia nigra pars compacta (SNpc) of the midbrain.[1] The most common mutation associated with PD is c.6055G>A (p.Gly2019Ser) in leucine-rich repeat kinase 2 (LRRK2) (GenBank: NM_198578.4).[2,3,4] LRRK2 is a multidomain protein involved in many cellular functions, including cell proliferation, survival regulation of neural stem cells (NSCs), and neurogenesis.[5,6] Altered neurogenesis and neurodevelopment have been suggested to have major implications in the development of neurodegenerative diseases, including PD.[7] various studies show an accelerated neuronal differentiation in LRRK2-mutant human cellular models, with a simultaneous impairment of DN development.[8,9,10] In particular, the interaction of LRRK2 with the canonical Wnt/b-catenin signaling pathway has been linked to the development of DNs through the regulation of axonal guidance, dendritic morphogenesis, and synapse formation.[11,12,13,14]

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