SNCA -targeted epigenome therapy for Parkinson's disease alleviates pathological and behavioral perturbations in a mouse model.

Alpha-synuclein (SNCA) overexpression is implicated in Parkinson's disease (PD) pathogenesis, making SNCA downregulation a promising therapeutic strategy. We developed a SNCA -targeted epigenome therapy using an all-in-one lentiviral vector (LV) carrying deactivated CRISPR/(d)Cas9, gRNA targeted at SNCA -intron1, and either the catalytic domain of DNA-methyltransferase3A (DNMT3A), or a synthetic repressor molecule of Krüppel-associated box (KRAB)/ methyl CpG binding protein 2 transcription repression domain (MeCp2-TRD). Therapeutic efficacy was evaluated in a new PD mouse model, generated with an adeno-associated viral vector carrying an engineered minigene comprised of the human (h)A53T- SNCA expressed via the human native regulatory region. Both therapeutic vectors reduced expression of α-synuclein in the substantia nigra (SN), with LV/dSaCas9-KRAB-MeCP2(TRD) demonstrating greater repression. LV/dSaCas9-KRAB-MeCP2(TRD) also significantly reduced pathological α-synuclein aggregation and phosphorylation (Ser129), and preserved tyrosine hydroxylase expression in the SN and the striatum. Behavioral analysis following LV/dSaCas9-KRAB-MeCP2(TRD) injection, showed significant improvement in motor deficits characteristic of our PD-mouse model. Safety assessments found normal blood counts, serum chemistry, and weights. Collectively, we provide in vivo proof-of-concept for our SNCA -targeted epigenome therapy in a PD-mouse model. Our results support the system's therapeutic potential for PD and related synucleinopathies and establish the foundation for further preclinical studies toward investigational new drug enablement.