From:  Gene therapy for Parkinson’s disease: a new frontier in neurodegenerative diseases

 Present developments in Parkinson’s disease preclinical gene therapy.

Animal modelsTargeted genes and vectorsAdministration processSafety/ToxicityOutcome measuresFollow-up and monitoringReference(s)
Adult male Sprague Dawley ratsSNCA, AAV-shRNABilateral injection into the SNNot safe: loss of striatal projecting dopamine neurons was evident in the vector injection siteReduced behavioral deficiencies in rats and silenced ectopically expressed SNCAFollowed up on [35][36]
Adult male Lewis ratsSNCA, AAV-shRNAUnilateral injection into the SNNo neurodegeneration or cell deathProtected the SN against the neurotoxic mitochondrial rotenone and lowered SNCA protein levels by about 35%[35]
Rhesus monkeysGDNF, AAV2-GDNFBilateral injection of AAV2-GDNF in the putamen after MPTP-lesioningThere was no adverse effectBilaterally increased striatal metabolism, indicating increased dopaminergic activity in the nigrostriatal pathway[37]
MPTP-lesioned macaque monkeyAromatic AADC, AAV2-hAADCUnilateral injection into the striatumSafe, minimal, or no side effectsPositron emission tomography-verified increase in AADC activity after 2 years. Consistently higher L-DOPA sensitivity in the treatment groupFollowed up for 8 years[38, 39]
MiceGBA1, AAV-GFP-micro RNA-GBAIntracerebroventricular administrationSafeSlower progression of neurological complications and an increased lifespan[40]
MiceGBA1, AAV-PhP.B-GBA1Tail vein injectionIt did not lead to evident dysfunction in the integrity and permeability of the BBBDecreased SNCA pathology and attenuated behavioral deficits[41]
Macaque monkeys (n = 4)GDNF, AAV5-GDNFUnilateral administration into the putamenNo adverse effectAt higher dosages, striatal and SN GDNF expression levels are greater[32]
Unilaterally MPTP-treated macaques (n = 15)GDNF, AAV2-GDNFBilateral delivery to the putamen following a lesionThe persistent high level of GDNF in the basal ganglia after AAV2-GDNF delivery to the putamen is well toleratedMotor behavior significantly improved at 24 months. Impact was proportionate to the lesion’s severity. A threefold rise in striatal dopamine[42]

SNCA: synuclein alpha; AAV: adeno-associated virus; shRNA: short hairpin RNA; GDNF: growth-derived neurotrophic factor; MPTP: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; AADC: L-amino acid decarboxylase; L-DOPA: levodopa; hAADC: human AADC; GBA1: glucocerebrosidase 1; GFP: green fluorescent protein; SN: substantia nigra; BBB: blood-brain barrier.