Single-cell transcriptomics of human iPSC differentiation dynamics reveal a core molecular network of Parkinson's disease

Parkinson's disease (PD) is the second-most prevalent neurodegenerative disorder, characterized by the loss of dopaminergic neurons (mDA) in the midbrain. The underlying mechanisms are only partly understood and there is no treatment to reverse PD progression. Here, we investigated the disease mechanism using mDA neurons differentiated from human induced pluripotent stem cells (hiPSCs) carrying the ILE368ASN mutation within the PINK1 gene, which is strongly associated with PD. Single-cell RNA sequencing (RNAseq) and gene expression analysis of a PINK1-ILE368ASN and a control cell line identified genes differentially expressed during mDA neuron differentiation. Network analysis revealed that these genes form a core network, members of which interact with all known 19 protein-coding Parkinson's disease-associated genes. This core network encompasses key PD-associated pathways, including ubiquitination, mitochondrial function, protein processing, RNA metabolism, and vesicular transport. Proteomics analysis showed a consistent alteration in proteins of dopamine metabolism, indicating a defect of dopaminergic metabolism in PINK1-ILE368ASN neurons. Our findings suggest the existence of a network onto which pathways associated with PD pathology converge, and offers an inclusive interpretation of the phenotypic heterogeneity of PD. Gabriela Novak et al. utilize scRNA-seq to investigate expression profiles in iPSC-derived midbrain dopaminergic neurons from Parkinson's disease patients or healthy controls. Their results suggest a core molecular network associated with Parkinson's disease pathology, and provide a future resource for investigation of this critical disorder.

Automated summary

This study used single-cell RNA sequencing and gene expression analysis to investigate the differentiation of midbrain dopaminergic neurons in Parkinson's disease. The results revealed a core network of genes that interact with pathways associated with Parkinson's disease. These findings are important for understanding the pathology and phenotypic heterogeneity of Parkinson's disease.