Development and validation of an expanded antibody toolset that captures alpha-synuclein pathological diversity in Lewy body diseases

Abstract

The abnormal aggregation and accumulation of alpha-synuclein (aSyn) in the brain is a defining hallmark of synucleinopathies. Various aSyn conformations and post-translationally modified forms accumulate in pathological inclusions and vary in abundance among these disorders. Relying on antibodies that have not been assessed for their ability to detect the diverse forms of aSyn may lead to inaccurate estimations of aSyn pathology in human brains or disease models. To address this challenge, we developed and characterized an expanded antibody panel that targets different sequences and post-translational modifications along the length of aSyn, and that recognizes all monomeric, oligomeric, and fibrillar aSyn conformations. Next, we profiled aSyn pathology across sporadic and familial Lewy body diseases (LBDs) and reveal heterogeneous forms of aSyn pathology, rich in Serine 129 phosphorylation, Tyrosine 39 nitration and N- and C-terminal tyrosine phosphorylations, scattered both to neurons and glia. In addition, we show that aSyn can become hyperphosphorylated during processes of aggregation and inclusion maturation in neuronal and animal models of aSyn seeding and spreading. The validation pipeline we describe for these antibodies paves the way for systematic investigations into aSyn pathological diversity in the human brain, peripheral tissues, as well as in cellular and animal models of synucleinopathies.

Therapeutic Implications and Regulations of Protein Post-translational Modifications in Parkinsons Disease

“…A fraction of alpha-synuclein from Lewy bodies is monoubiquitinated, and recent research sheds light on the role of this monoubiquitination in Lewy body formation, suggesting a link to the autophagic pathway (Engelender 2008 ; Sahoo et al 2022 ; Jang 2022). The E3 ubiquitin ligase SIAH, present in Lewy bodies, monoubiquitinates alpha-synuclein at lysines associated with Lewy bodies ( Sahoo et al 2022 ; Jang 2022; Altay et al 2023 ). Monoubiquitination by SIAH promotes alpha-synuclein aggregation into amorphous aggregates and increases inclusion formation in dopaminergic neurons (Engelender 2008 ).…”