Unraveling the Complex Interplay between Alpha-Synuclein and Epigenetic Modification

Alpha-synuclein (aS) is a small, presynaptic neuronal protein encoded by the SNCA gene. Point mutations and gene multiplication of SNCA cause rare familial forms of Parkinson's disease (PD). Misfolded aS is cytotoxic and is a component of Lewy bodies, which are a pathological hallmark of PD. Because SNCA multiplication is sufficient to cause full-blown PD, gene dosage likely has a strong impact on pathogenesis. In sporadic PD, increased SNCA expression resulting from a minor genetic background and various environmental factors may contribute to pathogenesis in a complementary manner. With respect to genetic background, several risk loci neighboring the SNCA gene have been identified, and epigenetic alterations, such as CpG methylation and regulatory histone marks, are considered important factors. These alterations synergistically upregulate aS expression and some post-translational modifications of aS facilitate its translocation to the nucleus. Nuclear aS interacts with DNA, histones, and their modifiers to alter epigenetic status; thereby, influencing the stability of neuronal function. Epigenetic changes do not affect the gene itself but can provide an appropriate transcriptional response for neuronal survival through DNA methylation or histone modifications. As a new approach, publicly available RNA sequencing datasets from human midbrain-like organoids may be used to compare transcriptional responses through epigenetic alterations. This informatic approach combined with the vast amount of transcriptomics data will lead to the discovery of novel pathways for the development of disease-modifying therapies for PD.

Automated summary

Alpha-synuclein (aS) is a protein encoded by the SNCA gene that is involved in Parkinson's disease (PD). Mutations and multiplication of the SNCA gene lead to familial forms of PD. Misfolded aS is cytotoxic and forms Lewy bodies, a hallmark of PD. The expression of SNCA and epigenetic alterations play a role in the pathogenesis of sporadic PD. RNA sequencing and informatic analysis of human midbrain-like organoids can provide insights into novel pathways for the development of PD therapies.