Single-cell transcriptomics and in vitro lineage tracing reveals differential susceptibility of human iPSC-derived midbrain dopaminergic neurons in a cellular model of Parkinson's disease.
Advances in stem cell technologies open up new avenues for modelling development and diseases. The success of these pursuits however rely on the use of cells most relevant to those targeted by the disease of interest, for example, midbrain dopaminergic neurons for Parkinson's disease. In the present study, we report the generation of a human induced pluripotent stem cell (iPSC) line capable of purifying and tracing nascent midbrain dopaminergic progenitors and their differentiated progeny via the expression of a Blue Fluorescent Protein (BFP).  This was achieved by CRISPR/Cas9 assisted knock-in of BFP and Cre into the safe harbour locus AAVS1 and an early midbrain dopaminergic lineage marker gene LMX1A, respectively. Immunocytochemical analysis and single cell RNA sequencing of iPSC-derived neural cultures confirms developmental recapitulation of the human fetal midbrain and high quality midbrain cells. By modelling Parkinson's disease-related drug toxicity using 1-Methyl-4-phenylpyridinium (MPP+), we showed preferential reduction of BFP+ cells, a finding demonstrated independently by cell death assays and single cell transcriptomic analysis of MPP+ treated neural cultures. Together, these results highlight the importance of disease relevant cell type in stem cell modelling. Overall design: single cell RNA sequencing data of of human induced Pluripotent Stem Cells (iPSC) derived into dopaminergic (DA) neurons. iPSC-DA were either challenged with MPP+ and non challenged (basal) for 3 main groups given their sorting status. The dataset consist of a total of 6 samples, three groups of cells according to their sorting status: non sorted (NS), sorted BFP positive (LMX1A+) and sorted BFP negative, and two treatment conditions (basal or treated with MPP+).