Parkinson's Disease (PD) is the second most prevalent neurodegenerative disorder after Alzheimer's disease and is closely associated with aging (Armstrong and Okun, 2020). One of the processes linked to aging and neurodegenerative diseases is cellular senescence, a homeostatic response aimed at preventing the proliferation of damaged cells. Notably, cellular senescence has been observed in the Central Nervous System (CNS), affecting both neurons and glial cells. Several triggers of cellular senescence exist, including oxidative stress and mitochondrial dysfunction (Kritsilis et al., 2018).

Mitochondria play a pivotal role in maintaining cellular respiration through the oxidative phosphorylation system and are significantly implicated in PD pathogenesis (Tassone et al., 2023). The accumulation of alpha (α)-synuclein oligomers initiates mitochondrial membrane permeabilization and leads to direct toxicity by increasing the formation of reactive oxygen species (ROS) (Chen et al., 2023). ROS generation not only inflicts irreversible damage on mitochondria and their electron transport system, but also affects cell membranes and activates pro-apoptotic cascades, ultimately resulting in neuronal death and the development of PD (Olagunju et al., 2023).

Among the proteins responsible for maintaining the balance of ROS are Peroxiredoxins (PRDXs), a superfamily of thiol peroxidases with six isoforms distributed throughout mammalian cell compartments. PRDX1, 2, and 6 are located in the cytoplasm, PRDX4 resides in the endoplasmic reticulum, PRDX3 in mitochondria, and PRDX5 in mitochondria, peroxisomes, and cytoplasm (Bryk et al., 2000).

PRDX3 plays an essential role in maintaining mitochondrial redox homeostasis and is particularly significant in inflammatory processes (Cox et al., 2009). Blocking the expression of PRDX3 in dopaminergic cells has been shown to increase their susceptibility to oxidative stress (De Simoni et al., 2008). A mutation in the leucine-rich repeat kinase 2 (LRRK2) gene enhances its phosphorylation activity, with PRDX3 being one of its target proteins. When PRDX3 is inactivated through phosphorylation, oxidative stress is heightened, leading to neuronal death. Furthermore, there is a direct association between the LRRK2 gene mutation and sporadic PD (Angeles et al., 2011).

Gene therapy offers a promising avenue for treating neurodegenerative diseases by enabling the expression of therapeutic genes in various affected cell types within the CNS. A key objective of gene therapy for neurodegenerative diseases is to express genes that restore the homeostasis of the brain's antioxidant defense system (Sun and Roy, 2021).

Given the established link between mutations in LRRK2, environmental factors, and increased oxidative stress that culminates in neuronal death due to reduced expression of PRDX3 at the cellular level, a viable strategy to counteract these oxidative processes involves the use of genes encoding antioxidant enzymes (Houldsworth, 2024), such as PRDX3.

In previous studies, a CPP-based (cell penetrating peptide) delivery system was developed, incorporating the Asn194Lys mutation at the acetylcholine receptor binding site of the RVG9R peptide (mRVG9R). This complex enhances the transfection efficiency of a reporter gene in neurons and glial cells in the cortex, hippocampus, and striatum regions of the murine brain (Villa-Cedillo et al., 2017, Villa-Cedillo et al., 2019). Recently, we demonstrated that Cerebral Dopamine Neurotrophic Factor (CDNF) overexpression by this CPP-based delivery system (mRVG9R) prevents motor-cognitive dysfunction in a Parkinson's disease animal model (Villa-Cedillo et al., 2023). In this study, we employed the mRVG9R delivery system to investigate antioxidant gene therapy using the PRDX3 gene in an animal model of PD.