Striatal small RNA remodeling in MPTP-induced Parkinson's disease highlights coordinated downregulation of mitochondrial tsRNAs.

Parkinson's disease (PD) is characterized by progressive nigrostriatal degeneration, yet the contribution of modification-rich small RNAs to PD pathology remains unclear. Here, we used PANDORA-seq to profile the striatal small RNA landscape in a subacute MPTP-induced mouse model of PD. MPTP-treated mice exhibited significant motor deficits together with reduced striatal tyrosine hydroxylase and dopamine transporter expression, confirming successful model establishment. Small RNA profiling revealed that transfer RNA-derived small RNAs and ribosomal RNA-derived small RNAs, rather than microRNAs, dominated the striatal small RNA transcriptome. Among the dysregulated small RNA classes, mitochondrial tsRNAs showed the most prominent and coordinated downregulation. Bioinformatic analysis suggested that predicted targets of differentially expressed mt-tsRNAs were enriched in synaptic organization, presynaptic function, membrane contact sites, and lipid-related pathways. In SH-SY5Y cells, transfection of an mt-tsRNA mimic partially reversed MPP+ induced increases in reactive oxygen species and restored mitochondrial membrane potential. These findings provide a modification-aware small RNA landscape of the PD striatum and identify mt-tsRNA downregulation as a notable feature of MPTP-induced parkinsonism.