Abstract
Objective:
Validate the rescue potential of SLP-2 induction for α-synuclein (aSyn)-induced mitochondrial pathology and neurodegeneration in two complementary models: human induced pluripotent stem cell (hiPSC)-derived dopaminergic (DA) neurons of Parkinson’s disease (PD) patients with SNCA (aSyn) mutations and a mouse model of aSyn neuropathology.
Background:
Accumulating evidence reveals mitochondrial dysfunction as a key factor in the pathophysiology of PD, and mitochondrial defects are also part of the pathogenic mechanisms induced by aSyn. Stomatin-like protein 2 (SLP-2) is located in the inner mitochondrial membrane, acting as a scaffold regulating mitochondrial function, integrity and bioenergetics.
Methods:
Mitochondrial function was assessed in hiPSC-derived neurons from 2 PD patient lines (aSyn locus triplication (3xSNCA), and A53T SNCA mutation) and 2 control lines. Assays included: oxygen consumption rate, oxidative stress, mitochondrial membrane potential; mitochondrial morphology was assessed through immunofluorescence staining (anti-GRP75 antibody) as well as S129 phosphorylated aSyn co-localization with mitochondria and amount (anti-GRP75 antibody and anti-pS129-aSyn). A mouse model of aSyn neuropathology was generated through AAV-mediated overexpression of human A53T-aSyn in mouse substantia nigra pars compacta (SNpc) DA neurons. Targeted overexpression of SLP-2 in the DA neurons of the SNpc was achieved through unilateral injection into the SNpc of an AAV encoding a Cre-dependent human SLP-2 in DAT-Ires-Cre mice.
Results:
We have identified phenotypes of mitochondrial dysfunction in SNCA mutant hiPSC-derived DA neurons, including oxygen consumption and oxidative stress, which can be mitigated by a moderate enhancement of SLP-2 expression, thus conferring protection against αSyn toxicity. Additionally, targeted SLP-2 overexpression in DA neurons of the SNpc of an A53T mutant mouse model of PD ameliorated motor deficits by preventing DA denervation in the striatum and the loss of tyrosine hydroxylase-positive cell bodies in the SNpc.
Conclusions:
SLP-2 represents a novel molecular target able to boost mitochondrial function and neuronal survival for αSyn-induced PD.