Preclinical Studies and Transcriptome Analysis in a Model of Parkinson's Disease with Dopaminergic ZNF746 Expression

Background: The parkin-interacting substrate (PARIS, also known as ZNF746) is a transcriptional repressor, whose accumulation and phosphorylation play central pathological roles in Parkinson's disease (PD). PARIS-induced transcriptional repression of PGC-1α or MDM4 contributes to mitochondrial dysfunction and p53-dependent neuron loss in PD. Despite the important role of PARIS in PD pathogenesis, unbiased transcriptomic profiles influenced by PARIS accumulation in dopaminergic neurons remain unexplored.

Methods: We engineered Tet-Off conditional transgenic mice expressing PARIS in dopaminergic neurons, driven by DAT-PF-tTA driver mice. The conditional PARIS transgenic mice were characterized by PD-associated pathologies, including progressive dopamine cell loss, neuroinflammation, PGC-1α repression, and mitochondrial proteome alteration. Motor impairment was assessed using pole and rotarod tests. L-DOPA and c-Abl inhibitors were administered to PARIS transgenic mice to evaluate their therapeutic efficacy. The transcriptomic profiles and gene ontology clusters were analyzed by bulk and single-nucleus RNA-seq for the ventral midbrains from PARIS transgenic and age-matched controls.

Results: Conditional dopaminergic PARIS expression in mice led to the robust and selective dopaminergic neuron degeneration, neuroinflammation, and striatal dopamine deficits, resulting in L-DOPA-responsive motor impairments. Consistent with the results of previous reports, PARIS suppressed dopaminergic PGC-1α expression, disturbed mitochondrial marker protein expression, and reduced COXIV-labeled mitochondria in dopamine neurons. Pharmacological inhibition of c-Abl activity in PARIS transgenic mice largely prevents PD-associated pathological features. Unbiased transcriptomic analysis revealed PARIS-regulated differentially expressed genes (DEGs), both collectively and in a cell-type-specific manner, along with enriched biological pathways linked to PD pathogenesis. Single-cell resolution transcriptomic analysis confirmed repression of PGC-1α and several mitochondria-related target genes in dopaminergic cells. Additionally, we identified distinct glial cell subpopulations and DEGs associated with PD pathogenesis.

Conclusions: Conditional PARIS transgenic mice recapitulate robust and dopaminergic neuron-selective pathological features of PD, allowing the preclinical evaluation of antisymptomatic and disease-modifying therapeutic strategies within a couple of months. Based on this new PD mouse model, we provide unbiased bulk and single-nucleus transcriptomic profiles that are regulated by PARIS and potentially contribute to PD pathogenesis. A PD mouse model with flexible pathology induction capacity and a whole transcriptome could serve as a useful resource for translational PD research.