Triplication of SNCA Gene Impairs Metabolic and Differentiation in iPSCs-derived Neuroprogenitor-like Cells

OLIVEIRA LMA; FALOMIR LOCKHART LJ; SCHUELE B; ARNDT-JOVIN DJ; BOTELHO MG; JOVIN TM

Córdoba

Workshop; AvH Kolleg 2017 Córdoba; 2017

Alexander von Humboldt Club Argentina

Parkinson?s disease (PD) is the 2nd most common neurodegenerative disorder and affects between 1 to 2 % of the population above 60 years-old. Its pathologic hallmark is the functional loss of dopaminergic neurons and the appearance of intracellular lipoprotein aggregates, constituted mainly by amyloid fibrils of the protein α-Synuclein (aSyn). Although most PD cases are idiopathic (also termed sporadic), a series of mutations in PARK genes are known and are usually correlated with familiar forms of the disease and/or early onset. We studied metabolic changes and neuronal differentiation of induced Pluripotent Stem-like cells (iPSCs) that were derived from a patient with a 4 Mb triplication that includes the SNCA (PARK1) gene (SNCAx3 cells) and an age-matched healthy relative (Control cells) under normal and environmentally stressed conditions to model in vitro gene-environment interactions which may play a role in the initiation and progression of PD.The iPSCs lines were initially committed to a neuronal linage, where SNCAx3 cells showed impaired viability, energetic metabolism and stress resistance to starvation and toxicants. A two-steps differentiation protocol was then employed to obtain neuron-like phenotypes in vitro. SNCAx3 cells exhibited a delayed and decreased capacity to differentiate into mature-like neurons. Differentiated SNCAx3 cells showed decreased neurite outgrowth and lower electrophysiological activity. Knockdown by shRNAi against aSyn systematically and significantly ameliorated SNCAx3 defects. Results suggest a two-fold aSyn overexpression is sufficient to set the stage for decreased developmental fitness, accelerated aging, impaired neuronal differentiation and increased neuronal cell loss. Significant work is still required to identify and describe the molecular mechanisms responsible for the gain of toxic function of aSyn. Perspectives of present projects under development will be presented.