Lentiviral vector delivery of parkin prevents dopaminergic degeneration in an α-synuclein rat model of Parkinson's disease

TLDR

Parkinson’s disease is marked by progressive loss of midbrain dopamine neurons and Lewy bodies, and mutations in genes such as α‑synuclein and parkin—whose loss of E3‑ligase activity causes early‑onset parkinsonism—highlight parkin’s essential role in neuronal survival. The study aimed to test whether overexpressing wild‑type rat parkin could protect against A30P α‑synuclein toxicity in a rat lentiviral PD model. Using a lentiviral vector, the authors overexpressed wild‑type rat parkin in rats expressing mutant human A30P α‑synuclein to assess neuroprotection. Parkin overexpression reduced α‑synuclein‑induced neuropathology, preserving tyrosine hydroxylase‑positive neurons and terminals, increased hyperphosphorylated α‑synuclein inclusions, and suggests parkin gene therapy as a promising PD treatment.

Abstract

Parkinson's disease (PD) is characterized by a progressive loss of midbrain dopamine neurons and the presence of cytoplasmic inclusions called Lewy bodies. Mutations in several genes including α-synuclein and parkin have been linked to familial PD. The loss of parkin's E3-ligase activity leads to dopaminergic neuronal degeneration in early-onset autosomal recessive juvenile parkinsonism, suggesting a key role of parkin for dopamine neuron survival. To evaluate the potential neuroprotective role of parkin in the pathogenesis of PD, we tested whether overexpression of wild-type rat parkin could protect against the toxicity of mutated human A30P α-synuclein in a rat lentiviral model of PD. Animals overexpressing parkin showed significant reductions in α-synuclein-induced neuropathology, including preservation of tyrosine hydroxylase-positive cell bodies in the substantia nigra and sparing of tyrosine hydroxylase-positive nerve terminals in the striatum. The parkin-mediated neuroprotection was associated with an increase in hyperphosphorylated α-synuclein inclusions, suggesting a key role for parkin in the genesis of Lewy bodies. These results indicate that parkin gene therapy may represent a promising candidate treatment for PD.