engleski

GENETIC MECHANISMS OF LYSOSOMAL DYSFUNCTION IN PARKINSON’S DISEASE – the effect of novel variants on alpha- synuclein accumulation

Accumulation of misfolded proteins in the brain is the main pathological hallmark of neurodegenerative diseases, including Parkinson’s disease (PD), suggesting that inadequate clearance of aggregation-prone proteins plays an important role in the disease pathogenesis. Studies on the rare inherited forms of PD have highlighted disturbed aSyn clearance through the autophagy-lysosomal pathway (ALP) as a key mechanism leading to PD. In order to characterize the putative underlying genetic mechanisms leading to ALP dysfunction in PD, we performed comprehensive analysis of genetic variants in ALP genes in PD patients. The study included 65 PD patients and 25 healthy control subjects. Genetic variants were ascertained using the custom LYSOGENE targeted next-generation sequencing (NGS) panel, containing a comprehensive set of 440 ALP related genes, as well as genes previously implicated in familial forms of PD. In order to assess the technical variability, we analyzed the samples using the SureSelect (Agilent) and Nextera (Illumina) library preparation kits. We identified a significant number of ALP gene variants among PD patients when compared to control subjects, with 815 variants pertaining to 290 genes present exclusively in PD patients. These variants were involved in over 50 biological processes, with the greatest enrichment observed in categories of lysosome organization, organic substance transport, abnormal myelination and sphingolipid metabolism. In contrast, variants found exclusively in healthy subjects were not related to specific biological pathways. Based on the NGS data, we selected genes ARSD, GALC, IDUA and LRBA with the most over- represented genetic variants in PD patients and investigated their effects on lysosomal impairment, aSyn accumulation and neurotoxicity using the neuroblastoma SH-SY5Y cell lines stably expressing human alpha-synuclein.. The results were compared to the effects of the knock-down of a known lysosome-related gene, ATP13A2, which causes a rare autosomal recessive form of juvenile-onset atypical Parkinson disease (PARK9). Our knock-down experiments confirmed the link between lysosomal impairment and aSyn accumulation. In total, our results strongly suggest that specific variants in ALP genes may contribute to lysosomal dysfunction in PD. Furthermore, these genetic variants may modulate aSyn clearance, thus promoting the PD pathology

Parkinson’s disease, autophagy-lysosomal pathway, genetic variants

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