Unilateral rNurr1-V5 transgene expression in nigral dopaminergic neurons mitigates bilateral neuropathology and behavioral deficits in parkinsonian rats withα-synucleinopathy

Parkinsonism by unilateral,intranigralβ-sitosterolβ-D-glucoside administration in rats is distinguished in that theα-synuclein insult begins unilaterally but spreads bilaterally and increases in severity over time,thus replicating several clinical features of Parkinson’s disease,a typicalα-synucleinopathy.As Nurr1 repressesα-synuclein,we evaluated whether unilateral transfected of rNurr1-V5 transgene via neurotensin-polyplex to the substantia nigra on day 30 after unilateralβ-sitosterolβ-D-glucoside lesion could affect bilateral neuropathology and sensorimotor deficits on day 30 post-transfection.This study found that rNurr1-V5 expression but not that of the green fluorescent protein(the negative control)reducedβ-sitosterolβ-D-glucoside-induced neuropathology.Accordingly,a bilateral increase in tyrosine hydroxylase-positive cells and arborization occurred in the substantia nigra and increased tyrosine hydroxylase-positive ramifications in the striatum.In addition,tyrosine hydroxylase-positive cells displayed less senescence markerβ-galactosidase and more neuron-cytoskeleton markerβIII-tubulin and brain-derived neurotrophic factor.A significant decrease in activated microglia(positive to ionized calcium-binding adaptor molecule 1)and neurotoxic astrocytes(positive to glial fibrillary acidic protein and complement component 3)and increased neurotrophic astrocytes(positive to glial fibrillary acidic protein and S100 calcium-binding protein A10)also occurred in the substantia nigra.These effects followed the bilateral reduction inα-synuclein aggregates in the nigrostriatal system,improving sensorimotor behavior.Our results show that unilateral rNurr1-V5 transgene expression in nigral dopaminergic neurons mitigates bilateral neurodegeneration(senescence and loss of neuron-cytoskeleton and tyrosine hydroxylase-positive cells),neuroinflammation(activated microglia,neurotoxic astrocytes),α-synuclein aggregation,and sensorimotor deficits.Increased neurotrophic astrocytes and brain-derived neurotrophic factor can mediate the rNurr1-V5 effect,supporting its potential clinical use in the treatment of Parkinson’s disease.

Cerebral dopamine neurotrophic factor transfection in dopamine neurons using neurotensin-polyplex nanoparticles reverses 6-hydroxydopamine-induced nigrostriatal neurodegeneration

Overexpression of neurotrophic factors in nigral dopamine neurons is a promising approach to reverse neurodegeneration of the nigrostriatal dopamine system,a hallmark in Parkinson's disease.The human cerebral dopamine neurotrophic factor(h CDNF)has recently emerged as a strong candidate for Parkinson's disease therapy.This study shows that h CDNF expression in dopamine neurons using the neurotensinpolyplex nanoparticle system reverses 6-hydroxydopamine-induced morphological,biochemical,and behavioral alterations.Three independent electron microscopy techniques showed that the neurotensin-polyplex nanoparticles containing the h CDNF gene,ranging in size from 20 to 150 nm,enabled the expression of a secretable h CDNF in vitro.Their injection in the substantia nigra compacta on day 21 after the 6-hydroxydopamine lesion resulted in detectable h CDNF in dopamine neurons,whose levels remained constant throughout the study in the substantia nigra compacta and striatum.Compared with the lesioned group,tyrosine hydroxylase-positive(TH^(+))nigral cell population and TH+fiber density rose in the substantia nigra compacta and striatum after h CDNF transfection.An increase inβIII-tubulin and growth-associated protein 43 phospho-S41(GAP43 p)followed TH^(+)cell recovery,as well as dopamine and its catabolite levels.Partial reversal(80%)of drugactivated circling behavior and full recovery of spontaneous motor and non-motor behavior were achieved.Brain-derived neurotrophic factor recovery in dopamine neurons that also occurred suggests its participation in the neurotrophic effects.These findings support the potential of nanoparticle-mediated h CDNF gene delivery to develop a disease-modifying treatment against Parkinson's disease.The Institutional Animal Care and Use Committee of Centro de Investigación y de Estudios Avanzados approved our experimental procedures for animal use(authorization No.162-15)on June 9,2019.