TARGET-seq: Linking single-cell transcriptomics of human dopaminergic neurons with their target specificity

Area of Science:

• Neuroscience
• Molecular Biology
• Genomics

Background:

• Dopaminergic (DA) neurons show diverse characteristics, including morphology, location, and disease vulnerability.
• Single-cell RNA sequencing (scRNAseq) revealed extensive molecular diversity within DA neurons, but functional and anatomical correlations remain unclear.

Purpose of the Study:

• To link the transcriptional profiles of DA neurons to their specific axonal targets in the forebrain.
• To determine if molecular subtypes of DA neurons correlate with their functional roles and classical A9/A10 classifications.

Main Methods:

• Development and application of TARGET-seq (Tagging projections by AAV-mediated RetroGrade Enrichment of Transcriptomes).
• Linking single-cell transcriptomes with specific forebrain projection targets of DA neurons.

Main Results:

• Identification of molecularly distinct subclusters of human DA neurons.
• Demonstration of a clear correlation between DA neuron transcriptome and axonal target specificity.
• Discovery of potential transcription factors controlling DA neuron subtype identity during development.

Conclusions:

• TARGET-seq enables the classification of DA neurons based on molecular identity and target-specific connectivity.
• Findings provide a foundation for designing next-generation A9 and A10 enriched DA neurons for drug screening and cell-based therapies.